Cat Hulbert: How I got rich beating men at their own game - <AUTHOR> http://www.bbc.com/news/magazine-38103674 <comment><USER2> >In the tiny group of gamblers who have become top players at both blackjack and poker, there is only one woman.In her own words, Cat Hulbert describes how she got rich beating male opponents - and the casinos - and explains why in her view women are innately better at poker than men.

Yeah... about that. If there's really only one woman "top player", I don't see much support for her _view_.

I played poker for decades, and one thing I learned was it's a lot easier to lie to yourself than the other people at the table.</comment>


CakeML – A Verified Implementation of ML - <AUTHOR> https://cakeml.org/ <comment><USER2> The example implementation of Unix cat(1) is... intimidating!

[https://github.com/CakeML/cakeml/blob/master/examples/iocatP...](https://github.com/CakeML/cakeml/blob/master/examples/iocatProgScript.sml)

<comment><USER3> It is possible I am misunderstanding something, but I am pretty sure that is not cat(1) implemented in CakeML. It is an implementation of cat(1) verified using the same HOL libraries, tactics, etc. that they used to verify the implementation of CakeML. I didn't look closely enough to see if they have gone all the way and reimplemented HOL inside of CakeML.

<comment><USER4> If I recall correctly, most CakeML code is actually written in HOL4 and then translated down to CakeML, and compiled to machine code from there. Unfortunately there isn't very much in the way of documentation or examples for writing concrete CakeML, as the developers seem to use it more as an intermediate representation.

Edit: The page describes two frontends. The first is a "proof-producing synthesis" of a CakeML AST from "ML-like functions in HOL". This is what I believe is the more typical use case of CakeML. The second frontend is a more traditional frontend which parse concrete CakeML syntax.

</comment></comment></comment><comment><USER5> Where do people usually use Standard ML type languages? What are these most suitable for? (Please excuse me for a lame question. I am an amateur.)

<comment><USER6> Whenever this comes up, the answer seems to be "for programming language research and proofs in academia" and not much else.

It's a pity. SML is in many ways a joy to work with. The language doesn't change, which is a nice thing in itself in the current climate, but it has many things people still look for in modern languages (type inference, pattern matching, a module system). Multiple compliant compilers are available that produce fast code. The syntax is delightful, relying on neither brace delimiters nor syntactic whitespace. The language and Basis library are small enough that a developer can realistically aim to learn the whole thing. It is a comfortably idiomatic general-purpose functional language: lacking object or procedural syntax but relaxed about side-effects and occasional use of mutable types.

There are problems. Everyone will have their own list of things they expect a language to have, that SML lacks (mine: a map container in the standard library; record updating without rebinding all the elements individually; universal printf/toString, no matter how hacky). There is no standard foreign- function interface for calling native libraries, and no standard memory model - each compiler has its own. There is no standard build system (though I dunno, maybe this is a good thing). Libraries are sorely lacking, although those written many years ago usually still work. Because the language is a stem for academic developments, there are several variations that are intriguing but not actually compatible - CakeML seems to be an example, as it doesn't support functors or records.

I find SML pretty nice for writing small command-line utilities - like a functional alternative to Go or Python.

<comment><USER7> > It's a pity. SML is in many ways a joy to work with. The language doesn't > change, which is a nice thing in itself in the current climate, but it has > many things people still look for in modern languages (type inference, > pattern matching, a module system). Multiple compliant compilers are > available that produce fast code. The syntax is delightful, relying on > neither brace delimiters nor syntactic whitespace.

is it now ? Caml has been taught for a long time to a lot of to-be engineering students in france, and it was frankly almost universally hated ; likewise for people that are taught LISP.

<comment><USER6> > is it now ?

Well of course I think so, since I said it... But -

> Caml has been taught for a long time to a lot of to-be engineering students > in france, and it was frankly almost universally hated

It's possible to wonder why a language like SML doesn't get more use outside academia, since so many people have been taught it as students. And it seems a reasonable explanation that many people who were taught these languages simply disliked the experience. If you're forced to learn a weird non-procedural language with no obvious application and a super-picky type checker that you can't understand, why would you like it?

I had a vaguely similar experience myself, when taught SML as a student in the 90s. I enjoyed it as an exercise, but by the end of the course I still didn't have any useful intuition for how to write a whole program in it. Meanwhile over on the C++ course, the object/procedural mix seemed to make more obvious sense as a way to structure things.

Now, after years working in C++, I think of SML as the easier language and in many ways more natural.

</comment></comment></comment></comment><comment><USER8> Online SML (SMLNJ): [https://www.tutorialspoint.com/execute_smlnj_online.php](https://www.tutorialspoint.com/execute_smlnj_online.php)

I really liked SMLNJ plus there's MLTON which is a highly optimizing SML compiler, albeit not so friendly with error messages (or it wasn't when I used it).</comment>


Ask HN: How to think about retention when the goal is churn? - <AUTHOR> I'm running a medical device startup. We make a treatment for depression. A discussion that often comes up is how we should think about and present our retention numbers. Since, ultimately our goal is to make our users recover from depression, and churn. Im looking for articles or other resources discussing growth and retention for these types of businesses. Or does anyone have any thoughts on this?
Dating apps have the same problem to some extent I guess.
This is a great article about growth, but I feel it doesn't really apply to our case: https://www.ycombinator.com/library/59-how-to-set-up-hire-and-scale-a-growth-strategy-and-team <comment><USER3> I haven't seen articles about this, but it comes down to this: your app needs a way to differentiate good churn (solved the problem) from bad churn (merely stopped using the app). An exit poll would be unlikely to get used by those whose problems weren't solved, so you'd have to get more creative than that.

That said, in your case, I'm skeptical that you'll have much hidden good churn in the early days. Depression seems like a long-lasting enough problem - <USER2> one that requires ongoing maintenance - that I'd defer this question until you're receiving anecdotes like "3 months using your app has changed my life! Thank you!" every week (like dating sites do from people in new relationships). Make sure users know you value those stories. When emails like that start showing up regularly, like weekly, then maybe good churn is big enough to be worth trying to calculate. Also, you'll have some actual examples that show how success manifests in app usage.)

(Obvious exception if your app is totally transactional, like a directory of therapists and all you do is connect the patient. If you're providing help over time, some users will thank you if it works.)

<comment><AUTHOR> Thanks for your great thoughts. I agree and this is what we are trying to do. We collect a lot of great testimonials/reviews and have an exit poll to try to understand why ppl leave. Our main objective is ofc treatment success, something we can track well.

But in these times when many VCs are looking for SaaS models this issue is a bit tricky.

</comment></comment><comment><USER4> One of my startup friends brought up that there's a billion dollar company whose work is funerals. I joked that they're doing pretty well for a company with 0% retention rate.

But how does such a company do well? Their focus is customer acquisition and referrals. It's perfect for something like curing depression too.

One of my clients is a mental health app. What we do is track their feedback on discomfort levels (physical, mental, emotional, visual) and how it increases or decreases as the treatment progresses. The payment system has been either pay one shot the first time or via donation. I'm wary of anything that charges for a subscription.

</comment><comment><USER5> > _Dating apps have the same problem to some extent I guess._

No. I think Kent Beck tweeted something along those lines, that the mere fact one was still using the app meant the app failed to do the "job to be done" and my reply was that the tweet assumed that search would stop once a match was found, when clearly it wasn't necessarily the case. Many users do concurrent processing of matches, with some being better than others as their processing algorithm is more efficient, and they can handle more IO and compute workloads. Some do round-robin. Though others pin one thread for processing matches sequentially.

I think this is different. This is similar to hospitals optimizing for patients not coming back after coming in (mitigation), and systems being improved to _prevent_ "failure demand".

What you can draw inspiration from is "remote patient monitoring". I think you have to find differences in _behavior_ from metrics and dimensions. There's that scene from the "Apollo 13" movie where the characters rip off vitals monitoring electrodes and the ground person freaks out looking at the telemetry data thinking they had lost the crew.

I also think the hypothesis that the goal is "churn" is to be revisited. Can we view your device as something that accompanies someone suffering from depression until they recover, and then _preventing_ them from relapse and regression. Your device helps get _better_ , and it is a spectrum, not a binary "depressed"/"not depressed". Similar to physical fitness, you don't stop once you're _there_ , because _there_ is dynamic. So your product adapts and can provide value throughout the journey, as opposed to punctual.

It's not a wedding planner one needs punctually, it's more like a buddy who will be there at the wedding, during the divorce, after a hangover, at the gym, and much more. Support.

So, what are the behaviors exhibited by people who are depressed, by people who are recovering, by people who're giving up (maybe throwing the device). Can you detect those?

You may have started in a niche thing with depression, but could eventually later expand to wellness.

</comment><comment><USER6> Don't call it churn. Call it "cured". In fact, your success metrics should depend on how many clients you acquired and how many you cured. Imagine saying:

"Over the years, we have helped 1000+ clients get better/cured".</comment>


Secrets Of Freemium Pricing: Make The Cheapskates Pay - <AUTHOR> http://onstartups.com/tabid/3339/bid/37737/Secrets-Of-Freemium-Pricing-Make-The-Cheapskates-Pay.aspx

<comment><USER2> This is one of the better articles I've read on HN ever I think. More of this.

</comment><comment><USER3> Great tips. Need more articles like this. Thanks.</comment>


Floyd Zaiger, a fruit innovator to the world (2011) - <AUTHOR> http://www.sfgate.com/bayarea/article/Floyd-Zaiger-a-fruit-innovator-to-the-world-2368432.php

<comment><USER2> If you find this interesting, the story of Luther Burbank would be a good choice too:

[http://www.amazon.com/Garden-Invention-Burbank-Business- Bree...](http://www.amazon.com/Garden-Invention-Burbank-Business- Breeding/dp/0143116894/)</comment>


In 'Flipped' Classrooms, a Method for Mastery - <AUTHOR> http://opinionator.blogs.nytimes.com/2013/10/23/in-flipped-classrooms-a-method-for-mastery/?_r=0

<comment><USER2> Great piece that breaks down the value of the Flipped Classroom model.20 yrs from now people are going to look back and say "I can't believe teachers would spend 4-10 hrs per week standing in front of a classroom and regurgitating memorized materials! That's what videos are for!" (hear sound of hand hitting the forehead) This is timely because we;re in the midst of Flipped Classroom week, so for more information you can checkout our blog [http://studysoup.wordpress.com/](http://studysoup.wordpress.com/) (sry it's also connected to our company StudySoup, but it's still interesting stuff)</comment>


Running bash commands in the background properly - <AUTHOR> http://felixmilea.com/2014/12/running-bash-commands-background-properly/ <comment><USER2> I found 'screen' to be pretty handy for running scripts in the background. Then you can also reattach later to look at stdout as it's running.

<comment><USER3> Screen or tmux. I tend to prefer tmux, but the both have this ability. I'm actuality surprised that there isn't a more elegant choice other than redirecting stdout and stderr to /dev/null where you can fork jobs to a background and reattach later to see the tty. Is there a shell that has a job queue that can be accessed from any number of shells?

<comment><USER4> There's this for attaching a running program to your terminal when it is not started in screen: [https://github.com/nelhage/reptyr](https://github.com/nelhage/reptyr)

</comment></comment></comment><comment><USER5> Understanding whether background jobs get killed (via SIGHUP) or orphaned is not obvious without reading about the huponexit shopt. I've found some recent distros to not enable huponexit by default for login shells, and so this isn't always an issue.

More importantly, understanding how your jobs behave when your SSH session is killed can be a huge timesaver.

</comment><comment><USER6> The random shell output from "background" apps never bothered me that much ;-) Crunchbang you can just press F2 and get auto-complete and launch commands with no shell output. Ubuntu has something similar. If you have terminator, just split the pane if you need a fresh one, or drag the terminal to another workspace and it's out of the way. Also tmux has ^bd to "detach" I think.

</comment><comment><USER7> Wouldn't it be better to simply do

        "$@" "${FD[@]" &

And also remember to

        alias ds='ds '

to enable alias expansion.

<comment><AUTHOR> would you mind explaining why that might be better?

<comment><USER7> It avoids a call to eval, which is always good. It's also a bit simpler.

</comment></comment></comment><comment><USER8> Added to /bin/sh</comment>


Construction begins on Jeff Bezos' $42M 10,000-year clock - <AUTHOR> https://www.theverge.com/tldr/2018/2/20/17031836/jeff-bezos-clock-10000-year-cost <comment><USER2> Seems a shame the article didn't mention _Anathem_ , the amazing novel that focuses on the clock itself and the Long Now concept in general.

</comment><comment><USER3> The linked article is a little light on detail. I found this to be a much more interesting explanation of the why/how/where: [https://www.techradar.com/news/why-is-jeff-bezos- building-a-...](https://www.techradar.com/news/why-is-jeff-bezos-building-a- giant-millennial-clock-inside-a-mountain)

</comment><comment><USER4> [http://www.10000yearclock.net/index.html](http://www.10000yearclock.net/index.html)</comment>


Strikingly Creates Simple, Beautiful Web Sites in Minutes - <AUTHOR> http://lifehacker.com/5989963/strikingly-creates-simple-beautiful-web-sites-in-minutes <comment><USER2> Suggestion: Make it more obvious that your Terms[1] and Privacy Policy[2] texts are actually links. Or maybe you aren't expecting anyone to actually read that?

Probably a 'design' decision -- but then I clicked on them and they're just plain text files that aren't even formatted to be readable.

(Yes, I realize I'm being harsh here, but really. They're explicit .txt files. Come on.)

[1] <http://www.strikingly.com/terms.txt>

[2] <http://www.strikingly.com/privacy.txt>

<comment><USER3> I for one love this! More sites should make documents like this available in pure-text formats.

Granted, the jarring transition should be avoided, but I believe all documents should be available in an array of formats; html, json, txt.

<comment><USER4> Yeah me too. Being able to easily grab the documents is pretty good. Whenever I've had documents like that on any of my sites I save them as a .txt file but format them using markdown.

</comment></comment></comment><comment><USER5> Someone mentioned the other day that "beautiful" is overused. I think I agree: the websites may look unique, but I'm not sure beautiful is the right term. I think polished may be better.

I want it to actually mean something, dammit.

<comment><USER6> <http://www.strikingly.com/site22261-1363092318> it's beautiful

</comment></comment><comment><USER7> I was trying to scroll through the home page on my laptop, using the arrow keys, and it didn't work. When I pressed the down arrow, it scrolled me to the next section, but some sections were too tall and didn't fit on my screen.

Specifically, it's the Beautiful mobile pages section, that features a picture of a laptop and says "Our responsive templates look great on any device, automatically." Ha.

<comment><AUTHOR> This is part of the design of our templates - the content of each section can certainly be taller than the height of the screen, but we still keep the arrow key controls so viewers can navigate quickly through the page.

</comment></comment><comment><USER8> My fault for not reading the fine print. Created my site and was ready to buy it but realized the site has to remain hosted on strikingly servers. Would love to pay a one-time fee to download the source code for site I created and upload it to my own server.

By the way this was the easiest, most beautiful web site I ever created. I do NOT have an eye for design and this really made me feel like I had a good looking site even though all I did was put my info in a template. So thank you :)

<comment><USER9> Thanks a lot for your support and kind words! We don't have a function for you to download the source code yet, but we might think about offering that function in the near future. Sorry that it wasn't clear to you. Definitely let me know if you have any other feedback!

<comment><USER10> I just want to register my interest for what nvr219 said above. Upon completion of the site if that was an option I would have bought it by now. If you introduce that feature for somewhere between $5-10$ and I'll buy the source code.

<comment><USER8> I would pay $10 easy -- considering the amount of time this could save me probably would go for $20 a pop (not sure if other people would pay that much though).

</comment></comment></comment></comment><comment><USER11> First, I don't appreciate having to give you my (fake) email address before I can see the pricing.

I would also suggest making it easy to replace images, especially the logo and the hero elements, with plain text boxes (textured/gradient/solid background). That might work better for boring businesses than stock photos.

Otherwise, nice little service, wish you best of luck with it!

</comment><comment><USER12> I don't mean this specifically about your site, but most of the sites like these where the user is trying something new, don't put a barrier asking for an email and expecting him to register. Allow him to start using your tools right away and then if he deems it worthy he'll register anyway since he needs to save the damn thing.

Right now, all I did was go to 10minutemail.com and grab a temporary email. Look I get it you're a new service and you promise to never never ever spam me. But after being burnt a thousand times no sensible user in his sane mind would give you his email address that easily. Allowing one to try before registering may increase coding complexity, but it'll drastically lower the barrier.

<comment><USER13> "We won't ever spam you, but we will send you a pointless email about a minor change in our TOS or a new feature in 6-9 months' time, once you've completely forgotten who we are and that you ever signed up for us. This email will ding your phone at 4am if you live anywhere that isn't San Francisco."

<comment><USER14> If you have your email address set to trigger your phone at all times, why the hell would you give it to random websites?

<comment><USER15> That's exactly their point - they wont.

</comment></comment></comment></comment><comment><USER16> Is it safe to say it's a direct competition with Weebly?

<comment><AUTHOR> We're both trying to make website building simpler for non-coders. Weebly is a powerful solution that allows people to build traditional desktop website. We take a different "mobile first, web second" approach. Our websites are simpler, and the key values we bring to users are cross platform optimization and fast set up.

<comment><USER16> Sorry maybe I didn't the concept of "mobile first, web second". From strikingly website, it looks like it's doing both mobile and web at the same time. So shouldn't it be "mobiel and web first" more precise instead?

</comment></comment></comment><comment><USER17> What about businesses that aren't apps or "sexy?" Say an accounting firm or some other professional services. I always struggle to fill in the massive image requirements of the front page sliders of these kinds of templates for "boring" businesses. I don't think these businesses should be forgotten, though.

The editing interface is fantastic, nonetheless. Great job.

<comment><USER9> That's a great point. We actually have a lot of small businesses using Strikingly, including accounting and law firms. We realized that picking good images is a long and hard process, and we're building up an asset library with good images for people to choose from. Do you think this helps? Thanks a lot for the feedback!

<comment><USER18> I think providing large, quality images is above and beyond the call. Anything toward that is pure bonus IMO.

<comment><USER9> Awesome to hear that! It should be done soon.

</comment></comment></comment></comment><comment><USER19> That logo has some major (anti aliasing?) issues on the edges of its letters.

<comment><AUTHOR> Thanks for pointing this out! There are some small issues with hi-res screens. We're fixing it now.

</comment></comment><comment><USER20> Will there be a mobile app to manage your site and view stats ?

<comment><USER9> Hey Mark, view stats is a great idea. We'll think about having an app to help manage the site as well. Will keep you updated. Thanks!

</comment></comment><comment><USER21> Blah, aren't there a million of these easy templating sites by now? Didn't onepagerapp steal the rest of the market?

</comment><comment><USER22> I couldn't sign up since the reg form suggests my email is invalid! (You can see my email in my profile).

<comment><USER23> User E-mail addresses are not shown by default; you have to put it in the "About" section (along with whatever other info you want to make public, aside from some site stats for your user name).

</comment></comment><comment><USER24> I always chuckle a little when a design-oriented company has a non-retina website.

<comment><USER25> I bought my rMBP this week specifically to take note of how my site looks on high res displays. I'm shopping for photographers and surprisingly few have "retina support".

</comment></comment><comment><USER26> in the Pro plan, will I be able to connect 5 custom domains to my 5 sites?

<comment><USER27> Someone please answer this. If this is true you will have a pro sale within 15 minutes of me reading it.

<comment><USER27> I went ahead and got a Pro plan and it appears this is the case.

</comment></comment></comment><comment><USER28> Is there an open source script witch scrolling page effect like in Strikingly?

<comment><USER29> ..and can release the flying monkeys?</comment></comment>


Are you really happy? - <AUTHOR> http://online.wsj.com/article/SB114263698678301765.html

<comment><USER2> Okay, that is quite interesting and I'm all for say, improving design to make people happier when they are using a product. I like being happy.

But I don't think this addresses what I see the real shortcoming of using focus groups at all - an over-reliance on the first impressions. A good example for this is drinks. If you go into Starbucks and get a premixed drink (say, their Strawberry Creme), it tastes good for the first few sips. By the time you are getting down to the bottom of the cup you realise it is disgustingly sweet. I think what happens in that situation is that they try all these formulations on some people, but it is just a fleeting taste that they are comparing.

The real question for me is not how people feel about your product on the first try (as long as they don't hate it!). The question is how they feel after after they have used it for a while. It is difficult to see how measuring microsmiles gets you any traction on such a problem.</comment>


Tips on creating another layer of security with .htaccess  - <AUTHOR> http://www.0x000000.com/index.php?i=567

<comment><USER2> sweet post, i wanted to do that for a site i operate, who knows maybe i will put it in tonight.</comment>


Ask HN: How do you deal with phone scams? - <AUTHOR> A number of my close friends and relatives have fallen victim to phone scams. Either they received a scam call or reached out to a fake number listed on Google. What are some ways to avoid such scams? It'd be very helpful if you could share your experience and approaches you have explored to block/detect fake numbers. <comment><USER2> I use the "Blacklist Blocker" app for Android, which is available via F-Droid[1]. I have a very short whitelist of numbers from which I am willing to accept calls or texts, and everything else goes straight to /dev/null.

[1] [https://f-droid.org/en/packages/com.kaliturin.blacklist/](https://f-droid.org/en/packages/com.kaliturin.blacklist/)</comment>


Ask HN: Net neutrality - <AUTHOR> We've had net neutrality regulations for a couple of years now, but for decades before that we did not, and nothing bad happened. Why should I be concerned about those regulations going away if things were fine before they existed? <comment><USER2> >nothing bad happened.

That is your perception. Maybe you weren't around for Compuserve, AOL, and similar attempts at walled garden networks that fortunately crumbled largely because there was an open Internet.

A better way to look at it is that a lot of good happened with net neutrality. Both before and after the regulations. Before, because we effectively had net neutrality already without the regulations, as I'll expand on more below.

The Internet thrived, and the blossoming of the entire world of web content happened.

Small startups had the opportunity to expose new innovative services to customers and markets that they might have otherwise been locked out of due to entrenched big companies feeling threatened.

The creative explosion of stuff that ensued has been fantastic.

Not all of it is good, of course, but it's hard to deny that overall it's way better than what we would have had in a walled garden world.

Some of this happened before net neutrality regulations, but in an era that had a kind of defacto net neutrality simply because the stodgy old companies hadn't yet figured out how to get their grasp around the Internet. So when thinking about this it's useful to look past just the era of actual on-paper regulation to the previous era of defacto openness of the Internet. The regulations were about preserving openness which already existed, but which was threatened by greedy corporate interests as they increasingly gained clues about how to lock things down and stifle competition.

Why can't we go back to having net neutrality without regulations? Because as I said big corporate players have now figured out how to exploit the system to the point where they would quickly threaten the openness of the net. Not that they can succeed in doing it 100%... the internet is self-healing to an extent... but without the net neutrality regulations being in place, they can choke off more of it, which would be bad.

</comment><comment><USER3> I think the responses in this thread explain this quite well: [https://twitter.com/bcrypt/status/933036555001774080](https://twitter.com/bcrypt/status/933036555001774080)

To paraphrase, (as I understand it):

The FCC did have some rules about Net Neutrality (The FCC Open Internet Order for example), but they were struck down as a result of Verizon Communications Inc. v. FCC. To ensure the same protections, the FCC then reclassified Broadband as a utility. Pai's new rules would roll regulation will cause neither Title I nor Title II to apply to broadband carriers, entering us into new territory.</comment>


Ask HN: How to develop/plan a document format - <AUTHOR>

This is a question about how to approach the design and development of a document format.
The basic problem is this: in math (and other disciplines), we write a LaTeX markup file and then compile it to PDF. PDF is basically a paper simulator and lacks many features which webpages/sites can have.
An alternative would be to have a versatile but still constrained markup language (e.g. an extension of LaTeX, or a constrained org-mode) which can be compiled or "exported" to HTML among other formats.
Some of the benefits would include
- Folding of text: hiding parts of the document until further details are desired
- more sophisticated linking between (parts of) documents
- nonlinear/hierarchical document structure
- including media such as animation/tutorials
- running code in the document
The question is: how to approach the development of the system.  For example, many of the features could be implemented, say in jquery or some such, but the system should be independent of implementation.  How does one proceed in a future-proof way whereby the choices are not regretted down the line?
Note that this is not about typesetting -- I am aware of the web typesetting problem. This is about the inadequacy of PDF as a document format for the future. <comment><USER2> > How does one proceed in a future-proof way whereby the choices are not > regretted down the line?

What's wrong with HTML that has classnames, or the new data attributes that HTML5 has? They're not dependent on any one implementation and HTML seems like it's the most future-proof thing out there apart from plain text.

In order:

\-
Hide/Show this text.

\- Go somewhere

\- Hyperlink

\- <video src="hello.mp4" />

\- console.log('hello world!');

Almost any JS developer can make these work without any library, from what the browser provides, alone. Give the innerHTML to eval, for example. It seems like the most future-proof way to go, and I'll be happy to be proven wrong and find out about something I don't know about. But Markdown nor any of its derivatives don't seem to be good enough.

Of course, you could also write a Markdown parser that has constructs that will compile to the above too.

> This is about the inadequacy of PDF as a document format for the future.

And I'm guessing, since we're doing this over an HTML document, that that'll be sufficient instead.

<comment><AUTHOR> Thanks for the reply:

I don't know about HTML5, so I will look into that. But my concern is more about how to design the system. Let me explain.

LaTeX is quite a formidable system nowadays, with a well-developed markup language optimized for mathematics and technical writing, as well as a compiler which does advanced typesetting (for PDF output, that is). Because of the way the system is organized, there are thousands of packages available for LaTeX which essentially extend the markup language and provide new functionality to the compiler to produce diagrams, for example, or certain alternate PDF formats, etc. The amount of work done in the LaTeX domain in terms of development is quite amazing.

In view of this, is there a way of extending LaTeX in such a way that all this functionality ports over to the creation of more active documents/webpages?</comment></comment>


Logic programming in C++ - <AUTHOR> http://wordsandbuttons.online/logic_programming_in_cpp.html <comment><AUTHOR> There's Prolog online if you want to try it: [http://rextester.com/l/prolog_online_compiler](http://rextester.com/l/prolog_online_compiler)</comment>


Seth Godin on why he isn't naked on stage & great marketing advice. - <AUTHOR> http://thebln.com/2011/09/seth-godin-on-why-he-is-not-naked-on-stage-other-more-useful-insights-video-talk-transcript-from-business-of-software/

<comment><USER2> Transcript alongside the video is a great way of both experiencing the talk and also digesting and refering to snippets of real interest when sharing with others.

<comment><AUTHOR> Thanks. They are far from perfect but do give a good feel.

</comment></comment><comment><USER3> I thought that the transcripts were a very interesting read. He raises some very interesting points. Not that many issues transcribing verbatim either.</comment>


Learn how to spy on competition - <AUTHOR> http://survicate.com/blog/how-to-spy-on-competition/ <comment><USER2> People have been doing this for years and they just don't voice it out publicly. All in all, good article.

</comment><comment><USER3> good read

<comment><AUTHOR> Thanks!</comment></comment>


At Blackrock, machines are rising over managers to pick stocks - <AUTHOR> https://www.nytimes.com/2017/03/28/business/dealbook/blackrock-actively-managed-funds-computer-models.html <comment><USER2> It is interesting, but not all that surprising that ineffective management strategies are slowly being flushed out of the market. That human stock picking is pretty bad, is widely known, sorry for the pickers, but I'm sure there are other things that they can do to actually create instead of destroy value--reallocating their labor is a huge benefit for society.

The real questions for me with this transition though are:

-With all these people passively investing, are we going to see reduced competition within industries because you don't have active, non-diversified, significant, institutional shareholders to drive aggressive competition against other industry participants? In fact, we may get the opposite where institutional shareholders don't want to see aggressive competitive moves because it is profit destroying for them on both sides (aggressor spends money to return less than the defender loses in profit--lose, lose for investor in both companies win, win for the consumers of this industry).

-How good is price setting if there are less and less actively managed funds? Are there new inefficiencies that are created by all this passive investing?

-Where aren't the machines taking over? Obviously, something like replicating an index is a great exercise for automation and programming. But truly maximizing return? Who is successfully, consistently beating the benchmarks with active strategies automated or not?

<comment><USER3> Following a market cap index investing - the most popular method of passive investing - means buying a set of stock weighted by market cap _and then mostly doing nothing_. It's hardly the machines taking over. Algorithm investment is probably not passive investment.

<comment><USER4> Exactly, how can algorithm investing be truly passive investing?

There's a lot of confusion in the article.

<comment><USER5> Disclosure: I work for a company which does this stuff. I'm not in the financial programming side.

There are several things you can do.

For example, say you wanted to hold the S&P500, but as individual stocks rather than paying someone at a mutual fund or ETF to hold it for you. This might be beneficial in a number of ways, but it has the serious drawback of having to manage 500 entries. You might already own a dozen or two of those entries already, or you have overlapping purchases in other investments.

You could tell a smart portfolio management program to use the S&P500 list as a target, and tell it about all the rest of your current holdings. Then it could analyze your current portfolio each day and make recommendations about how to get closer to your target, while avoiding wash sales and duplicate purchases. If you trusted that program, you could feed the output to your brokerage and have the trades executed automatically. Or you could look at the output and make decisions about whether you want to make the changes. Either way, you are no longer doing analysis yourself, and you're edging closer to your target, at which point you would be passive.

On the other hand, suppose you wanted an approximation of the S&P500 -- a target that would give you most of the same exposure and opportunity, but had a reduced number of individual stocks. You could run simulations on subsets of the S&P500 until you got a group that performed sufficiently similarly to the whole thing - 300? 250? 100? 50? as you reduce the set size you reduce the fidelity of the model - and then buy and hold those.

You can do a lot with an algorithm, and if your strategy doesn't need to operate in realtime, it will certainly look passive compared to HFT bots. A human might not want to rebalance more than annually or quarterly, because it can be a lot of work -- but a robot has no problems doing all the calculations daily and looking for a sufficient reward to present to you.

<comment><USER4> Thanks for the explanation, there are 2 things I don't quite understand though.

What is the advantage of building a replica of the S&P500 with individual stocks rather than having it done with an index fund? Isn't the second option much cheaper?

Secondly, isn't finding a subset of the S&P500 and trying to replicate it still an active strategy?

<comment><USER5> I expect that there are tax advantages to holding individual stocks rather than an index fund.

Is finding a subset an active strategy? Depends. Do you do it every day, or do you figure out your subset and then buy and hold for fifteen years?

Is it passive when you rebalance against your target quarterly?

I think we can all agree that it's not passive when you are doing HFT, and anything which involves picking new stocks daily or weekly is active -- but having an algorithm do the rebalancing against your existing target daily and executing when a threshold is met? You're not making new picks, just readjusting against what you've already picked.

<comment><USER6> > I expect that there are tax advantages to holding individual stocks rather > than an index fund.

None that I am aware of. Mutual funds can force capital gains realization, but ETFs do not.[0]

IMO there's no reason to roll your own index fund when you can just buy an ETF with a very low expense rate. If you have enough money that rolling your own (costs a fair amount to manage) is cheaper than the public fee, you might be eligible for a special shareclass rate anyway.

[0]: [http://www.investopedia.com/articles/investing/090215/compar...](http://www.investopedia.com/articles/investing/090215/comparing- etfs-vs-mutual-funds-tax-efficiency.asp)

<comment><USER7> Here's one: as a US citizen living in Canada, I'm unable to invest in ETFs in Canada (e.g. Vanguard Canada's S&P500) without suffering punitive taxes and onerous reporting to the IRS. If it's an active investment, then it's fine, it's taxed as normal.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER8> It's not so much machines getting better. It's investors switching to low cost passive funds rather than giving 2% a year to pay for the managers next vacation home.

<comment><USER9> Reminds me of the story of the manager of CALPERS (California's public workers pension fund). Can't find the article but it focused on how hard work it is for a moneymanager to do nothing. CALPERS is showing good return for it's inactivity.

<comment><USER10> He's in Nevada actually

[https://www.fnlondon.com/articles/nevada-pension-fund- manage...](https://www.fnlondon.com/articles/nevada-pension-fund-manager-does- nothing-all-day-20161020)

<comment><USER9> Hah! That's why I couldn't find it! Could have sworn it was about CALPERS. Thanks! It was in some other publication thou (if my memory isn't Swiss Cheese).

<comment><USER10> Yeah there were a few articles about it. The first one I found when googling just now was WSJ but that's fully pay-walled at this point

</comment></comment></comment></comment></comment><comment> one-more-minute Interesting to note that BlackRock's Aladdin software platform, powering much of this stuff, is being largely written / re-written in Julia.

[https://juliacomputing.com/case- studies/blackrock.html](https://juliacomputing.com/case- studies/blackrock.html)

<comment><USER11> Does Julia have good substitutes for Numpy / Scipy / sk-learn / Pandas / Matplotlib / Keras / Tensorflow / Theano yet either natively (for Numpy) or from libraries (for others)? Ease of analysis being almost at the level of matlab is why I stick with python. I would love to be able to switch to something that doesn't have such a heavy handed approach at the top.

<comment> semi-extrinsic If I understand Julia correctly, "Numpy" is built into the core language - i.e. the basic Julia array class is fast like Numpy arrays and does what they do.

As for equivalents to Pandas, Matplotlib etc., Julia has thin wrappers around the Python versions of these so you can use them just like in Python with the same performance.

</comment></comment></comment><comment><USER12> This is for mutual funds, which are ultimately intended to operate under given parameters -- balancing a cocktail of risk, reward, timeframe etc. Seems natural that you'd eventually move to algorithms for this, particularly as information asymmetry drops or is negated by other factors.

This is really now becoming a form arbitrage between the mega-funds on a sizable, but discrete, chunk of the trading market. Probably the same chunk that's already reserved for market-makers who can (usually) succeed through volume and brute force alone.

I think this is a good thing - arbitrage is a terrific leveller for the rest of us. It opens up the real market for us small fry.

</comment><comment><USER13> Not to be skeptical, but Blackrock was never known as a stock picker's shop, it's a fixed income shop. The equities side has largely been a function of their indexed ETF biz.

If Fidelity or TR Price were going all in machine based stock picking, then this would be news.

</comment><comment><USER14> Reminds me of this art project by Michael Marcovici where they 'taught' rats to trade. Sadly no longer online. [https://web- beta.archive.org/web/20140220072141/http://www.r...](https://web- beta.archive.org/web/20140220072141/http://www.rattraders.com:80/methodology)

<comment><USER15> That was bizzare but interesting. Looking for more on it now. Thanks for sharing.

</comment></comment><comment><USER16> Hopefully, we can eventually cut down on fees with those mutual funds too.

You don't have to worry so much about algorithm engaging in insider trading or some other securities fraud. The auditors just have to look at the algorithm's data sources to verify the fund stays compliant with securities regulations.

Fewer costs (hopefully) mean fewer fees

</comment><comment><USER17> BlackRock isn't a whole lot more advanced than many other asset managers. So sure, Wall St. uses algorithms to trade, but that's not really news...

Separately, BlackRock bought FutureAdvisor so that it could use machines to do the opposite of picking stocks; i.e. rebalance assets using index funds. A very different proposition.

</comment><comment><USER18> It will be interesting to see what happens when machines and algorithms really start coming for jobs on that level. I wonder if far down the line, will there be one sole human at the top of all of this automation, protected from its outcomes?

</comment><comment><USER19> So... wait, this is what investment banks have been doing for literally over a decade, is this news? For legal accountability someone has to sign off on the orders but that's about it. The computers have been picking stocks for years.

<comment><USER20> exactly what i was thinking. does not seem remotely new.

</comment></comment><comment><USER21> Does the machine just run a random generator to pick the stock?

<comment><USER22> There's a back room with monkeys throwing darts somewhere :-)

<comment><USER23> No change then :)

<comment><USER22> Hey, it's how I pick stocks!

</comment></comment></comment></comment><comment><USER24> I wonder how much of this trend is helped by the stock market going mostly up and sideways in the past years. In that case passive investing is very good, you need to minimize fees. Timing the exit before the bubble bursts again and re-entering at the right time will be a big part of the long-term performance and I expect many humans to outdo the robotic overlords who will just stay invested.

</comment><comment><USER25> Hasn't the Aladdin system been doing this for a long, long time? Or was it actually semi-automated?

<comment><USER26> Aladdin simply provided portfolio managers with data. it did not pick stocks. the onus was on the portfolio managers to pick the best stocks given that data.

<comment><USER25> Thank you. I wssn't clear on it.</comment></comment></comment>


The result would be a catastrophe (1985) - <AUTHOR> http://www.lettersofnote.com/2009/10/result-would-be-catastrophe.html <comment><USER2> A classic tale of engineering gone wrong. Apropos, I designed high-efficiency 20 KHz inverters for the Space Shuttle crew quarters, flight hardware that ended up working flawlessly. But during the design phase, the primary Shuttle contractor revealed that my inverters would be exposed to much higher voltages than they had originally supposed.

When I saw this, I realized we would have to start over and choose different components able to tolerate the higher voltages. My managers disagreed, arguing that if we caused problems, we would be denied a follow-on contract for similar inverters to be deployed in the payload bay. The managers composed a reply to NASA in which there was no problem, things were fine, let's forge ahead.

I was a mere engineer, I had no management authority, and I hadn't been consulted about the reply. When I heard about it, I sat down and wrote a letter of resignation and pushed my letter into more hands than was absolutely necessary. I made some comparisons that at the time might have seemed over the top (like the Apollo file that killed three astronauts, a disaster resulting from lax oversight).

In my case, because of my having distributed the letter farther than was absolutely necessary, my managers were forced to reverse themselves, I was able to redesign my inverters in a safe way, and we got the follow-on contract in spite of not being seen as "team players".

Many years later, at the time of the Challenger disaster, it finally dawned on me that, had I disregarded the overvoltage issue as my managers had wanted me to, and if something had gone wrong, I would have been held personally responsible, because I was the only person with the level of technical knowledge required to make the call, and my managers could disavow any responsibility. At the time, I made the right decision, but for reasons that I hadn't fully thought out -- if my equipment had failed in-flight, I would have been held responsible, and that would have been a perfectly just outcome.

</comment><comment><USER3> Nothing I've worked on has been nearly to this scale, but having management understand and ignore warnings is commonplace.

Just today, I pointed out that a backend web service system for an important (HR) function was so insecure that simply putting a single quote in an end- user input field would crash it, and that a SQL injection would be trivial. After a little arguing from them ("You don't know what a SQL injection is") they changed their tune to "Just put a limit on the frontend", and when I told them that could be trivially bypassed, they said "No one will ever think to try that." When I pressed further, they continued to "It's an internal app, no one would attack it" then to "And do you want me to put locks on all the doors and cabinets around the office too?"

So that's a case where there's some reasonable level of understanding and just a refusal to act.

I also recall a time (at a different company) when I discovered a public read/write anonymous FTP server setup externally facing with no firewall rules. When I pointed out the problem, they said, "that's what our customers are used to, we're not going to change it." and when I pushed, "No one will ever find it anyways." Literally less than a month later that server was overrun with illicit content.

It happens. Unfortunately, as we've seen with the Volkswagen debacle as well, it happens even when regulation or (in the Challenger case) human life is on the line.

<comment><USER4> They possibly felt that you were suggesting it was a lot of work to fix this, when in reality it would take a couple of hours to add sanitization checks to the inputs.

You're also overestimating the business impact of a security breach. This is an area where people's moral compass overrides their shrewdness. Notice that Anthem is still in business despite the worst possible breach, for example.

It's worth trying to improve security, if possible. But it takes one of two things: (a) leverage, or (b) patience. One of the main reasons that companies get a security audit is because a different company forces them to. They get an audit in order to obtain a CFD (client facing document) saying that they are secure. Without this, the other company will not do business with them, which is the sole reason why the security audit happens.

The other way -- patiently pointing out ways of improving the situation, and explaining the business merits of allocating time to this pursuit -- does not usually result in meaningful security improvements. This is an unfortunate fact of the industry, partly because security breaches do not usually put a company out of business. There are exceptions to this, but that is the common case.

<comment><USER3> To be fair, it would be a lot of work to fix the backend. The SQL is dynamically generated for every request, and the code that does so is thousands of lines long, with nested subroutines that construct sub-portions of the query, so there is no easy way to check where things need to be parameterized. Also there is some injection from unusual places (like a search options object separate from the search criteria object which includes the ASC/DESC which, you guessed it, is directly injected).

Realistically, to be safe, you'd have to gut the whole thing and replace it. You can be a "little safe" by doing something silly like replacing ' with '' but that doesn't protect in non-string cases, etc, and I wouldn't propose a solution like that because it could give a false sense of security.

I understand the push-back. The backend is maintained by others and it would add to their workload to secure it. That's a real and actual cost.

As for the business impact, you are right. I just wanted it to be "on the table" that I informed people of the situation, so that if there is an exploit in the future, I don't get the "why didn't you tell anyone this was vulnerable?" or something like that.

<comment><USER4> An attacker can't necessarily leverage ASC/DESC injection unless multiple queries can be issued by a single SQL statement (i.e. injecting "ASC; SELECT * FROM...") which isn't commonly enabled in most database deployments. But there are probably other insecurities here.

The solution is to run every input through a function that replaces each single quote with two single quotes. That is all that's required to prevent SQL injection, since it's not possible to construct a valid query regardless of the injection point. (EDIT: This refers to string inputs. Numeric inputs are handled in the obvious way, as is ASC/DESC. Injection into an ORDER BY clause is not usually exploitable. These are all of the cases.)

If you propose this solution to management, they may be somewhat more likely to take action, since it can be applied to the existing system.

<comment><USER3> I respectfully disagree with your claim that replacing ' with '' will complete the security. Reason: there are non-string cases, so there exists concatenations like: "WHERE SomeNumber = " \+ inputValue + " ... "

but inputValue is a string (from untyped xml), but is put into SQL without quotes because SomeNumber is an int type in the database. Since the xml is constructed without validation, an attacker could put any value there, including strings to inject, and do so without using quotes.

<comment><USER4> Yes, numeric cases are solved by running the input through a function that allows only numeric characters, [-.0-9]. That's the only other case.

Management is more likely to listen to this, since it doesn't require a rewrite.

<comment><USER5> How can you be so sure that's the only other case?

</comment></comment></comment></comment></comment></comment></comment><comment><USER6> I worked in a company that made CNC machine tools at the time of the Challenger disaster. The actions of Roger Boisjoly gave me the courage to reject a demand from management that I add a "feature" to a control system I was working on to disable all safety lockouts from a single virtual switch.

I refused the assignment. When they didn't fire me on the spot I followed the managers who made the request and when they would ask another engineer to do it, I would warn the engineer that they could be held personally responsible for any injuries or fatalities that could occur.

I fully expected to be fired but surprisingly, management just gave up on the idea. Perhaps my insistence that it was a bad idea convinced them.

<comment><USER7> Perhaps they consulted with HR/Legal and were told firing you would be a bad idea.

<comment><USER8> Or Legal told them it was bad idea to ignore safety advice from their engineers?

</comment></comment></comment><comment><USER9> I'm not saying NASA didn't fuck up by any means. I'd just like to point out that hindsight bias is a very real effect that can have huge consequences when planning for future events: [http://lesswrong.com/lw/il/hindsight_bias/](http://lesswrong.com/lw/il/hindsight_bias/)

>Viewing history through the lens of hindsight, we vastly underestimate the cost of effective safety precautions. In 1986, the Challenger exploded for reasons traced to an O-ring losing flexibility at low temperature. There were warning signs of a problem with the O-rings. But preventing the Challenger disaster would have required, not attending to the problem with the O-rings, but attending to every warning sign which seemed as severe as the O-ring problem, without benefit of hindsight. It could have been done, but it would have required a general policy much more expensive than just fixing the O-Rings.

>Shortly after September 11th 2001, I thought to myself, and now someone will turn up minor intelligence warnings of something-or-other, and then the hindsight will begin. Yes, I'm sure they had some minor warnings of an al Qaeda plot, but they probably also had minor warnings of mafia activity, nuclear material for sale, and an invasion from Mars.

>Because we don't see the cost of a general policy, we learn overly specific lessons. After September 11th, the FAA prohibited box-cutters on airplanes—as if the problem had been the failure to take this particular "obvious" precaution. We don't learn the general lesson: the cost of effective caution is very high because you must attend to problems that are not as obvious now as past problems seem in hindsight.

<comment><USER10> I think your comment is great, but I have to disagree with one part in particular. I don't agree that it was a "some minor warning" when President Clinton told President Bush explicitly; "In his campaign, Bush had said he thought the biggest security issue was Iraq and a national missile defense. I told him that in my opinion, the biggest security problem was Osama bin Laden."

<comment><USER11> "Osama Bin Laden is dangerous" is pretty far from actionable intelligence, though. I think it's an example of hindsight bias to think that if President Bush had been more prudent in dealing with Bin Laden then the 9/11 attacks would have been prevented.

<comment><USER10> Your paraphrase is one thing.

When the current Commander in Chief of the United States of America, the most powerful military in the world, says "the biggest security problem [is] Osama bin Laden," that's something entirely different.

And frankly, I trust the opinion of Richard Clarke more than I trust yours OR MINE.

<comment><USER9> Except after 9/11 he did say that, and sent the entire military after him. And it took 10 years to find him.

<comment><USER12> To be fair, we spent most of the effort fighting in the wrong country (Iraq) chasing the wrong person (Saddam Hussein) who had nothing to do with orchestrating the attacks, nor had any viable "weapons of mass destruction" that were the purported reason for going after him in the first place.

<comment><USER9> That was 2 years later and had nothing to do with the search for bin Laden. Who they put out a huge search effort for, and continued doing so for the next 10 years.

</comment></comment></comment></comment></comment></comment></comment><comment><USER13> If you haven't read Richard Feynman's appendix to the Rogers Commission report on the Challenger disaster, I really recommend it: [http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/roger...](http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers- commission/Appendix-F.txt)

It's very readable and goes into a bunch of other issues at NASA at the time beyond the O-ring failure, which Feynman treats as a symptom of more general engineering and cultural problems.

<comment><USER14> Feynman is well-known for his TV appearance where he dramatically demonstrated what happened with the O-rings, live...but in his memoir, "What Do You Care What Other People Think?", he credits being inspired by General Kutyna, who had asked him to join the commission. Feynman describes that a random comment from Kutyna led him down the path of revelation:

> _Then he says, "I was working on my carburetor this morning, and I was > thinking: the shuttle took off when the temperature was 28 or 29 degrees. > The coldest temperature previous to that was 53 degrees. You're a professor; > what, sir, is the effect of cold on the O-rings?" "Oh!" I said. "It makes > them stiff. Yes, of course!" That's all he had to tell me. It was a clue for > which I got a lot of credit later, but it was his observation. A professor > of theoretical physics always has to be told what to look for. He just uses > his knowledge to explain the observations of the experimenters!_

 _However_ , Feynman admits at the end of his multi-chapter account of serving on the commission that Kutyna had coyly _played_ Feynman:

> _Another thing I understand better now has to do with where the idea came > from that cold affects the O-rings. It was General Kutyna who called me up > and said, "I was working on my carburetor, and I was thinking: what is the > effect of cold on the O-rings?" Well, it turns out that one of NASA's own > astronauts told him there was information, somewhere in the works of NASA, > that the O-rings had no resilience whatever at low temperatures—and NASA > wasn't saying anything about it. But General Kutyna had the career of that > astronaut to worry about, so the real question the General was thinking > about while he was working on his carburetor was, "How can I get this > information out without jeopardizing my astronaut friend?" His solution was > to get the professor excited about it, and his plan worked perfectly._

If we take Feynman at his word, to me this is a great description of how science and bureaucracy and invention (and, sometimes, disaster) works: it's not always just random eurekas, or study-real-hard-and-you'll-figure-it- out...sometimes the information is already well-known, and obvious, but for various logistical/political/bureaucratic reasons, it isn't immediately disseminated or explored.

via: Feynman, Richard P. (2011-02-14). "What Do You Care What Other People Think?": Further Adventures of a Curious Character (Kindle Locations 2923-2930). W. W. Norton & Company. Kindle Edition.

<comment><USER15> The astronaut who tipped Kutyna off was Sally Ride. He kept that secret until after she died. He talks about it in this oral history of the disaster from popular mechanics: [http://www.popularmechanics.com/space/a18616/an-oral- history...](http://www.popularmechanics.com/space/a18616/an-oral-history-of- the-space-shuttle-challenger-disaster/)

"Kutyna: On STS-51C, which flew a year before, it was 53 degrees [at launch, then the coldest temperature recorded during a shuttle launch] and they completely burned through the first O-ring and charred the second one. One day [early in the investigation] Sally Ride and I were walking together. She was on my right side and was looking straight ahead. She opened up her notebook and with her left hand, still looking straight ahead, gave me a piece of paper. Didn't say a single word. I look at the piece of paper. It's a NASA document. It's got two columns on it. The first column is temperature, the second column is resiliency of O-rings as a function of temperature. It shows that they get stiff when it gets cold. Sally and I were really good buddies. She figured she could trust me to give me that piece of paper and not implicate her or the people at NASA who gave it to her, because they could all get fired."

<comment><USER14> _Wow_...you know the bureaucracy is toxic if even an _astronaut_ as well known as Sally Ride is afraid to speak out.

<comment><USER16> ... after she had been _personally appointed by President Reagan_ to determine _that exact fact_!

(although the oral history above suggests that she was concerned for other people's careers, not her own, but it's still kind of amazing)

</comment></comment></comment></comment></comment><comment><USER17> It seems almost unbelievable how such a stern, concrete warning can be ignored. Of course, we look at this memo with perfect 20/20 hindsight, knowing that the O-ring issue caused a disaster.

I am genuinely curious why the warning was ignored. I am hesistant to believe it was through malice or sheer incompetence. Does upper managment get two overblown warnings per week by engineering, so that this critical warning was "drowned by the noise"? Or were there good (at the time!) reasons to focus on other issues first?

<comment><USER18> There was pressure to ignore warnings because President Reagan was scheduled to be present for the launch. In higher levels of management, things get more political. Looking good and getting exposure count for a lot. No one wants to be the guy that made nasa look bad by slipping the launch date. In tech, most managers tend to be rated by how well their projects meet schedules and how much operating expense they can minimize, since that's the only thing their managers have any sense of control over. Your boss doesn't want to take the heat for delaying project "glitter unicorn" by a week so you can fix 2 major security holes in the service, one which allows customers to login without a password. And this is why your company won't spend $500 for a data backup system or why it takes 4 months to get your broken keyboard replaced. It's turtles all the way up.

<comment><USER19> > There was pressure to ignore warnings because President Reagan was scheduled > to be present for the launch.

I never heard that before. Is there a source?

<comment><USER18> I was wrong--he wasn't going be attend, but there (allegedly) were plans to have a televised conversation between him and Christa McAuliffe during his State of the Union address that night.

However this may not be true. While trying to find an e-source, I read that there were some politically-motivated rumors that the white house ordered the shuttle to launch for this reason. Feynman investigated that rumor and didn't find any evidence that the white house ordered the launch.

It's possible the detail about an on-air tv conversation between the president and a schoolteacher astronaut could have been fabricated as well to make Reagan look bad, or it could have been based on elements of truth. For example she was expected to broadcast 2 lessons to students from space, so the capability definitely existed. It doesn't seem too far out that they would have liked for this conversation to happen during the State of the Union, though that doesn't mean the white house ordered the launch.

I read this in Edward Tufte's essay _Visual and Statistical Thinking_ ([http://www.edwardtufte.com/tufte/books_textb](http://www.edwardtufte.com/tufte/books_textb)), which discusses how better information displays might have convinced NASA management to postpone the launch. It also appears as a chapter in his book _Visual Explanations_.

I didn't have any luck finding sources on the internet (lots of keyword overlap). Tufte is much better informed than pretty much all of us, though it's possible he printed what amounts to an unsubstantiated rumor. FWIW he also served on the Columbia accident investigation board.

I think there were other pressures to launch as well. The launch date had been postponed 3 times already for various reasons. _Cynical danek: I wouldn 't be too surprised if some manager's performance review was based on how many launches took place on the scheduled date._

</comment></comment></comment></comment><comment><USER20> _Boisjoly later revealed this memo to the presidential commission investigating the disaster and was then forced to leave Morton Thioklol after been shunned by disgruntled colleagues._

I find this phenomenon so difficult to understand.

<comment><USER21> By ending up being the only one who was correct about a catastrophe warning, and being vocal about it in the aftermath, you somehow implicitly throw everyone else under the bus.

Since "everyone else" > "you", majority rules, you go.

It's a bureaucracy problem. I've seen it, and it's also gotten me at least once, when I decided to stick up for principles. My ego left intact, my job did not.

This is also why getting fired should not automatically carry a negative stigma.

I have a counterpoint- I bet that, given any risky endeavour, there are ALWAYS some naysayers/doubters. So the probability that _someone_ at an organization ends up being correct when a disaster occurs, is probably fairly high. Thus, just because you won the disaster prediction lottery, may not entitle you to as much acclaim as you might think.

<comment><USER22> > _I have a counterpoint- I bet that, given any risky endeavour, there are > ALWAYS some naysayers /doubters. So the probability that someone at an > organization ends up being correct when a disaster occurs, is probably > fairly high. Thus, just because you won the disaster prediction lottery, may > not entitle you to as much acclaim as you might think._

Conversely, achieving success despite taking a great number of risks in the process, may not entitle you to the acclaim that you do get.

</comment></comment></comment><comment><USER23> I remember the Challenger explosion like it was yesterday. I'll link here to a scan of the pages from Edward Tufte's book _Visual Explanations_ about what went wrong with the data analysis during the launch planning, which understated the risk of a launch in cold weather.

[http://williamwolff.org/wp-content/uploads/2013/01/tufte- cha...](http://williamwolff.org/wp-content/uploads/2013/01/tufte- challenger-1997.pdf)

<comment><USER24> But Boisjoly rejected Tufte's analysis

[http://www.onlineethics.org/CMS/profpractice/exempindex/RB-i...](http://www.onlineethics.org/CMS/profpractice/exempindex/RB- intro/RepMisrep.aspx)

<comment><USER25> Can you summarize one or two of Boisjoly's main points?

Tufte's pictures of the (superfluous) rocket graphics showing the temperature vs. his redrawing, placing temperature on the x-axis are very convincing.

<comment><USER26> Boisjoly's rebuttal is that

1) Tufte had temperature datapoints for the previous launches that the Boisjoly's team didn't know[1]. I assume "know" to mean the complete historical data wasn't all consolidated conveniently at his fingertips _before_ the disaster. Presumably, Boisjoly's team could have gotten it _if it had occurred to them_ to gather it. Essentially, Tufte had the benefit of "hindsight" to make his compelling diagram showing cause & effect.

2) GIGO garbage in is garbage out. The Tufte temperature datapoint assumes that the outside ambient temperature is equal to the O-ring temperature[2] so substituting one for the other is wrong. (E.g. It's wrong to put them both on the same X-axis.)

Quotes excerpted from [http://www.onlineethics.org/CMS/profpractice/exempindex/RB-i...](http://www.onlineethics.org/CMS/profpractice/exempindex/RB- intro/RepMisrep.aspx):

[1] _" He thus supposes that they knew the temperatures at launch of all the shuttles and, assuming they acted voluntarily, infers they were incompetent."_

[2] _" , in addition, mixes O-ring temperatures and ambient air temperature as though the two were the same."_

<comment><USER27> I thought the rebuttal was very well written, if a bit dense.

For (1), you're correct that the engineers did not have the historical data. More than that, though, it did occur to them to request the data, but they were stifled by Morton Thiokol Management (and NASA).

To start with, there were a variety of previous problems with the O-rings caused by variables that appear unrelated to temperature. These problems were resolved, but prevented anyone from seeing a pattern. It was only on the basis of the single data point in SRM 15 that Boisjoly requested temperature data in advance of the launch.

Obtaining such data was far from simple, because, as you mention, the temperature of the O-ring isn't the same as the ambient air temperature. Thus, obtaining the data was relatively involved and required knowing many variables: time on the pad, the gradient of ambient temperature, the temperature at which testing was conducted, and so forth. For this reason, the engineers didn't compile the data themselves (unclear what process they'd need to get the data).

The engineers thus requested the data in advance, but had not received it. They had precise data on only two data points (at 53 degrees and 75 degrees), so the rest of the data in the chart was compiled after the fact.

"The data necessary for a calculation of O-ring temperatures was thus not collected all along during the shuttle history. And when Boisjoly asked for that data in September, along with much other data, any one of which might have been the crucial missing piece to explain the anomalous cause, it was not supplied. In fact, the engineers received none of the data they requested."

</comment></comment></comment></comment></comment><comment><USER28> "Ach, damned engineers, what do they know about engineering!?" ~ Management, upon reading the memo.

Actually, more realistically:

"Brinton, do you know what this Boisjoly guy is talking about?"

"No Lund, I don't - his attitude is disappointing, we need team players."

"Thanks Brinton - I'll bring it up with his manager for his next performance review."

<comment> sjm-lbm To be honest, I think you are - to an extent - falling into the same trap that the managers fell into at Thiokol: namely, assuming that your view of the situation is complete and that input from other work groups can be disregarded.

In reality, it's a _very_ big problem for companies to disappoint their large customers (as NASA certainly was for Morton-Thiokol at the time), and I suspect that the engineers would have been quite annoyed at management if the ultimate result of a launch no-go was fewer contracts, lower pay and/or job losses.

This isn't to say that management did the right thing, of course, just that "lol management just throws some buzzwords around and never attempts to understand the problem" is basically the same attitude that caused this disaster - just seen from an engineering viewpoint.

<comment><USER28> I am "management" where I work, and I'd drive my company into the ground and make everyone unemployed, before I allowed my defective product to kill someone.

<comment><USER29> Duh. You think a single person at NASA would have reported otherwise had you asked them before the Challenger disaster?

Social pressure can influence people into engaging in wishful thinking. They made a horrible judgment call, and we should remember that that tragedy was authored by them. But if you think you NEVER would have fallen for it... you're not being self aware. There's a pretty decent chance you would have.

<comment><USER28> The trick is to not give two hoots about social pressure. Being on the spectrum can be an asset.

</comment></comment></comment></comment></comment><comment><USER30> As someone born in 1995, I don't have any real emotional connection to the Challenger explosion. It's pretty bizarre to think that children born after the 9/11 attacks will probably feel the same indifference.

<comment><USER31> If you are an engineer, it would be good to try to learn from this and similar accidents. I.e., noting your lack of emotional connection is beside the point, the question is, what can you take away from what happened?

<comment><USER30> Of course, it's extremely important. I'm currently listening to the Freakonomics podcast on the Challenger explosion[0]. I was only noting the difference being born a few years apart can make when it comes to significant shared cultural memories.

[0][http://freakonomics.com/2015/05/20/failure-is-your- friend-a-...](http://freakonomics.com/2015/05/20/failure-is-your-friend-a- freakonomics-radio-rebroadcast/)

<comment><USER32> You will notice this sort of thing more and more as time goes on.

For me the "ah hah" moment was when it hit me that "Where were you when you heard about Challenger?" was my generation's version of, "Where were you when JFK was assassinated?"

Another easily observed one is music. Very few people are aware of much that happened in popular music after they hit 25.

<comment><USER33> I'm turning 25 in two weeks. So this is it? 2015 was my last year of music? Damn...it went by so fast!

<comment><USER34> Quick, hurry.

You can listen through 65 years of pop music made so far. Then, if you live 80 years, you only lose about 45,8% of all pop-music you could have heard during your lifetime. That's not half bad.

If you include some blues, jazz and classical, that percentage goes down significantly.

Regards, 29 year old with 4 year long amnesia about music.

</comment></comment></comment></comment></comment></comment><comment><USER35> This letter is an excellent illustration of why good writing matters, and why bad writing can be disastrous.

The most important sentence in the letter ("The result would be a catastrophe of the highest order - loss of human life.") is at the end of the third paragraph, and is effectively hidden by two paragraphs of dense, technical jargon that I, as a layman, cannot understand at all.

I honestly think that if he had just taken that sentence and moved it to the end of the first paragraph, 7 astronauts' lives could have been saved.

<comment><USER36> I strongly doubt it and I don't think you've worked in an engineering environment if you think this is true.

This document is written as a credible engineering analysis of a distinct problem and uses extremely strong terms. It isn't addressed to the general public, or an article on Buzzfeed, it is an interdepartmental memo from an engineer signed by his manager to the Vice President of Engineering.

Your example of "clear writing" would have just made this engineer look hyperbolic and likely undermined the issue even more. In a document like this, stating the physical problem up front _is_ clear writing, and then, once the engineering problem is stated, he immediately states the possible outcome and then describes what he says as the management failure to allocate the appropriate resources, and how to fix it.

How it comes off to you as a layman doesn't dictate whether or not this is good writing. He wasn't writing it to you.

<comment><USER35> I respectfully disagree. Safety is of the highest priority, so if there's a serious risk to human life, there's nothing hyperbolic about drawing attention to it. If you can't do that, there's something very wrong with your engineering culture.

To help the busy reader, the first paragraph of a memo should summarize the whole document. (Like the abstract of a technical paper.) This document is about an engineering problem _and_ it's serious consequences, so they should both be mentioned in the first paragraph.

<comment><USER36> I think it's extremely misguided to assume that the problem here was a matter of writing style. I think it's naive to assume that the people who received this memo weren't aware that it was bringing attention to an engineering issue that could lead to loss of human life. I think it's misguided and not supported by the evidence to assume that was the gap in understanding that lead to the problem. They're working on rockets. People working on rockets know what the stakes are. These are the risks engineering projects like this are structured around dealing with.

And I think it's pretty disrespectful to the engineer who is still haunted by this to say that what he really should have done was switch some sentences around and that would have totally solved the problem.

This is a strongly worded document.

Making safety a priority doesn't mean starting every engineering document with the words "loss of life" which is a really common outcome of engineering failures on programs like this. Making safety a priority means putting the risk of an engineering failure up front and knowing that an engineering failure in a life-critical system is critical. Making safety a priority means people don't have to tell you what the stakes are every single sentence, because everyone already knows and so what you really communicate is how much risk there is, not the fact that risk exists. Making safety a priority means even if you're working on an engineering problem that wouldn't lead to loss of life, you fix the thing because you might be wrong and it might be part of a correlated failure one day that does lead to loss of life. Making safety a priority doesn't involve writing engineering documents in a way that makes them more amenable to skimming.

It's a rocket. Engineering doesn't have to go that far wrong on rockets for people to die. When someone sends a letter to a VP of engineering which begins with "This letter is written to insure that management is fully aware of the seriousness" then everyone who receives that memo is paying attention and if they aren't then it's not the writing skills of the people involved that are at fault.

I don't think a single person who was aware of the O-ring issue was unaware of the stakes. That didn't show up in any reports on the panel. What did show up was they estimated the risk of the problem wrong. The first sentence of this engineer's letter went towards establishing the seriousness of the engineering failure. Because that was the part that needed to be communicated most clearly.

<comment><USER35> Okay. You've convinced me. Thanks for taking the time to explain your thoughts on this. :-)

</comment></comment></comment></comment></comment><comment><USER37> Engineering degrees universally require a technical writing course. Engineers universally revile it as busy work. This memo is Exhibit A for why written communication is critical for engineering, and I imagine an assignment to rewrite this memo to be more effective would be a good way to underscore the importance of clear and concise writing.

<comment><USER38> I upvoted this comment because the point about the importance of writing. However, I don't think conciseness and clarity was the problem here. In 1985 if an engineer personally composed a long letter you should automatically know it's important. If you read this letter at all the danger is made clear.

<comment><USER39> The call to action was on the second page though - definitely try to keep it to one page in corporate communications class.

</comment></comment></comment><comment><USER40> For those interested, social scientists often refer to what happened with the Challenger as a "normal accident".

[https://en.wikipedia.org/wiki/Normal_Accidents](https://en.wikipedia.org/wiki/Normal_Accidents)

</comment><comment><USER41> What stands out to me the impact of loyalty on corruption. Despite doing obviously the right thing: _Boisjoly later revealed this memo to the presidential commission investigating the disaster and was then forced to leave Morton Thioklol after been shunned by disgruntled colleagues._

Elsewhere in the discussion[1], we learn that key information about the O-rings had to be carefully, anonymously disclosed to protect the jobs of several people, including a prominent astronaut.

How do we avoid corruption when loyalty uber alles is the rule of almost all organizations?

[1] [https://news.ycombinator.com/item?id=10992224](https://news.ycombinator.com/item?id=10992224)

<comment><USER34> For small enough organization that "loyalty uber alles" prevents corruption. What is small enough? For a military company it's around Dunbar number. Squad that actually works together on single issue is often optimal around 8 individuals. Company, squad and brigade are most important formations, as they have dis-proportionally high number of things expected to handle independently.

For this NASA o-ring bullshit, simplest solution seems to be having the technical managers and the astronauts in the same in-group. Now your loyalty is about not getting your mates killed.

If you need a big organization, the trick is to have that internal network of squads and companies to work somehow non-corrupt and nice manner. This is where it gets hairy. Basically you can go with assumption of corruption and apply "transparency" or monetary incentives (sub contractors). Or you can assume that corruption does not happen. Sometimes the mere assumption that corruption does not happen stifles it. Practically for big companies failing less than your competitors is adequate for success.

<comment><USER41> Some interesting ideas; thanks. I don't quite grasp a couple of them:

> For small enough organization that "loyalty uber alles" prevents corruption.

How? There are many, many cases of people covering up for their fellow squad members.

> Or you can assume that corruption does not happen. Sometimes the mere > assumption that corruption does not happen stifles it.

Hmmm ... that seems like a well-known recipe for encouraging corruption. How would that approach stifle it?

<comment><USER34> >How?

It's unlikely that one would be corrupt against ones squad members. So as squad member, you only have to worry about corruption of outside shit. People who affect you and are not member of same in-group are the problem from any individuals point of view.

>How would that approach stifle it?

Most people are good by nature. The only instance I've stolen from work was a situation where it was expected that I might steal from work. So I kind of showed to them that I'm more cunning than they are careful. A challenge. Another point comes from self image, if everybody sees you as corrupt asshole, you see yourself as corrupt asshole. So you might as well act on it.

In general people have strong tendency to act as is expected of them. Stronger than the tendency to act as they are told.

</comment></comment></comment></comment><comment><USER42> This was a terrible thing. So many saw this coming and nobody listened to them.

In my mind, what made this tragedy even worse was the way the program itself was conducted. You learn new modes of transportation and hardware by using it, many times to the point of exhaustion. We should have built a dozen orbiters and flown the shit out of them through hell or high water, learning as we went along. Instead we built 5 and every time something happened we backed farther away from the entire manned space program.

A lot of time was wasted, and the lessons we didn't learn? Somebody else is still going to have to learn them someday.

<comment><USER43> I think it's emblematic of the whole Shuttle program to look at the flight test program. There basically wasn't one. In particular, look at the various abort scenarios, and then look at the abort testing. Don't look too hard for the abort testing, because they didn't do any. There was pretty much zero resiliency in the system, and they knew it.

</comment></comment><comment><USER44> Here's an interesting thing about the Challenger (and Columbia) disaster: We find it to be particularly devastating, the same as a major natural disaster or terrorist attack. But on paper, they don't even compare. The explosion of the Challenger killed 7 people and cost NASA around $40 billion. The destruction of the world trade center killed over 2600 and the cost to the private insurers alone was over $40 billion. Hurricane Katrina killed over 1800 and cost at least $100 billion. Not even the same ballpark. So why the big emotional impact? Because they stood for something important.

</comment><comment><USER45> Today, there's no way I could get away with writing an entire page of context before getting to the impact. I wonder how much context the recipient had and what reading expectations were like back then...

<comment><USER46> Leaving aside the fact that the subject includes 'Potential Failure Criticality', the key impact line "The result would be a catastrophe of the highest order - loss of human life" occurs less than 150 words into this. It's the 5th sentence (though they're admittedly long sentences).

Are you having serious engineering-related discussions with your management where they can't read 150 words before getting to the hook? (serious question, not snark)

Is everyone communicating via twitter or something? (sorry, that was a bit of snark)

<comment><USER47> I disagree. This is a fairly poorly-written persuasive letter, and we have ample evidence for its lack of persuasive powers. The letter opens with useless content "This letter is written ..." which is self-evident. Then it proceeds to the grammatical error of "insure" which almost made me stop reading. If I was writing a letter like this, and I wanted it to have some effect, this would be the first sentence:

The total loss of a future shuttle mission and the death of its crew is a near certainty with our current booster o-ring design.

Then I would omit everything else in the original letter except the request for staffing.

<comment><USER48> While I agree with you about the difference between "insure" and "ensure," that's not a universally accepted grammar rule. I think the may even be in the minority; _The New York Times_ , for example, uses "insure" for all instances.

<comment><USER47> It does? I have a 5th Ed. New York Times Manual of Style and Usage right here and it clearly distinguishes between the two. Under the entries for both ensure (p 120) and insure (p 170) it gives examples of the other.

<comment><USER48> Well, I guess that's what I get for believing my first Google hit for "insure vs. ensure." Nonetheless, I see a lot of highly literate people using "insure" for all cases.

</comment></comment></comment></comment></comment></comment><comment><USER49> It is perhaps sad, but I'm heartened by this letter. I had heard that warnings were given in advance, but this is clear (in fact, I find the "catastrophe of the highest order" language to be less impressive than the clear and defined "loss of human life").

Why am I heartened to see that someone foresaw a lethal accident and was ignored? Because it was foreseen, and the consequences understood, with clarity. Getting people to take clear warnings seriously seems a more easily solved problem than getting us to be able to recognize the danger in the first place. A single person in management, or a few people, being dense is fixable. Groupthink where everyone assumes someone else is checking for problems and no one does is harder to fix.

Now, just because it's an easier problem doesn't make it an EASY problem, but still, easier.

</comment><comment><USER50> I bet there were other such warnings, many of them valid, that just didn't turn out to be catastrophic.

If there are any high level managers here, please tell me, does it seem like your people are constantly alerting you of dire risks? Does it feel like you are inundated with worriers?

</comment><comment><USER51> An piece NPR did on Boisjoly after he passed away:

[http://www.npr.org/sections/thetwo- way/2012/02/06/146490064/...](http://www.npr.org/sections/thetwo- way/2012/02/06/146490064/remembering-roger-boisjoly-he-tried-to-stop-shuttle- challenger-launch)

And an interview with one of Boisjoly's colleauges:

[http://www.npr.org/sections/thetwo- way/2016/01/28/464744781/...](http://www.npr.org/sections/thetwo- way/2016/01/28/464744781/30-years-after-disaster-challenger-engineer-still- blames-himself)

</comment><comment><USER52> In hindsight things are obvious.

I think the way to look at it is from the point of view that people have before the event happens. You also weigh in all the warnings that you are receiving.

No matter what you build, if it's complex enough you're always going to have individual predicting doom. The challenging part is filtering the signal from the noise and owning the decisions you make.

</comment><comment><USER53> Isn't something missing? I was under the impression that the accident happened due to the cold. Nowhere in the memo does it say anything about how to avoid the problem, nor does it call for a full stop of launches until its fixed. It seems to be referring to a known issue without explaining what that is or what to do - specifically. Or did I miss that?

<comment><USER54> Simplifying a bit...

They knew the o-rings were being eroded away during the flight, but the secondary o-ring was 'squishy' enough to fill in the gap and prevent the erosion from actually destroying the vehicle. While the erosion was unexpected, they figured the 'backup' was doing its job, and actually ended up increasing the predicted safety margin (i.e. it's only working 1/5th of the way through, so we have a 500% safety margin, yay! despite the fact that any erosion was unexpected in first place)

The problem was, the cold made the secondary o-ring stiff enough that it didn't 'squish' as much as it had in previous launches, so the o-ring failed completely.

</comment></comment><comment><USER55> Here is Richard Feynman talking about the issues [https://www.youtube.com/watch?v=4kpDg7MjHps](https://www.youtube.com/watch?v=4kpDg7MjHps)

Seems not very different from how companies are managed 30 years later.

</comment><comment><USER56> Imagine being on the team that discovered and warned about this issue, and then a year later watching the replays of the shuttle exploding on television. Just knowing that's what had happened and your worst fears at come true.

</comment><comment><USER57> My parents in law worked with Greg Jarvis at Hughes who was on that mission. They had a touching memorial at Hughes for his wife according to my mom in law. Very sad that it was preventable.

</comment><comment><USER58> National Geographic has an awesome video called "Challenger, The Untold Story" which highlights the communications breakdowns. google it

</comment><comment><USER59> Can you imagine this poor man's reaction as he watched the launch?

</comment><comment><USER60> I think many of us here have been Boisjoly at some point, though with much lower stakes. This is how people are, they want to do the thing. Doesn't matter how much you warn them.

</comment><comment><USER61> The transcript is incorrect. It uses "Manager" under Kapp's signature, instead of the original "Manger".

</comment><comment><USER62> If you don't stop the CO2 emission, the result would be a catastrophe.

Lets see how it will turn out now.

Edit: And yes, it is sarcasm, nothing changed or is going to change.

</comment><comment><USER63> I doubt anyone in the reagan admin could even understand this note its highly technical it was likely tossed out without ever being read.

<comment><USER64> This memo was not sent to the administration, it was sent to the management of Morton Thiokol, who could reasonably be expected to understand basic engineering phrases like "loss of human life."

It's a real PITA to engineer safe systems (see e.g. IEC 61508 and ISO 13849 in industrial automation), but it saves lives, and if you're in a position where Sales, Production, etc. is trying to get you to rush the Engineering work so they can make deadline, you've got to find the backbone to say "no," even if it hurts you professionally.

<comment><USER28> You'd think so, but they probably saw "loss of human life" and went "hysterical. ignore.".

It's actually really hard to warn people. Warn them loudly and strongly and they think you're scaremongering and being unnecessarily negative. Warn them quietly, and nobody listens. Warn them just right, and they'll take it under consideration, but go ahead anyway.

When of course the inevitable happens, as the guy who predicted doom, you'll be blamed, because "it wouldn't have happened if you hadn't made a self fulfilling prophecy".</comment></comment></comment>


The ratio of boys to girls at conception has been misunderstood - <AUTHOR> http://nautil.us/issue/27/dark-matter/this-gender-mystery-starts-nine-months-before-birth

<comment><USER2> Slightly off topic but the male/female ratio is very imbalanced in places. Having just moved back to Seattle from Tokyo, this imbalance is very prominent here, which wasn't noticeable in Tokyo. Just yesterday I went to a bar with a colleague. I counted 21 males, 0 females. That type of ratio isn't uncommon here it seems. A friend went to a yoga class with his girlfriend and he said more than half the class was male. They also took salsa lessons together and mentioned that men had to have other men as dance partners since there wasn't enough women to pair up with.

<comment><USER3> > _They also took salsa lessons together and mentioned that men had to have > other men as dance partners since there wasn 't enough women to pair up > with._

I wonder if this is mostly due to those men attending salsa classes hoping to meet women.

<comment><USER4> Hoping to meet women, or develop a talent/skill that they can use to impress women they meet elsewhere.

</comment></comment></comment><comment><USER5> In case you're not into skimming through the history, here's the nut graph:

"Any sex ratio much higher than 108 (52 percent male) at any time during pregnancy is essentially excluded by modern data. Past the middle of the second trimester the sex ratio is known with great accuracy, at least in industrialized countries with strong health systems and reliable vital statistics, because nearly every fetal death after that point is recorded. The sex ratio of 20-week fetuses is essentially identical to the secondary sex ratio: The numbers of deaths after that point is too small to make much difference, even if the stillborn were all male."

</comment><comment><USER6> A note to the reader: this article has far more questions than answers. It's still interesting, but know what to expect before you read it. Unlike some, this author is very careful about understanding the limits of what we know.

<comment><USER7> It seemed to make a pretty strong statement by the end: "The old story of high primary sex ratio — as high as 282 (74 percent male) by some accounts — declining rapidly and then steadily to birth, is gone. Any sex ratio much higher than 108 (52 percent male) at any time during pregnancy is essentially excluded by modern data."

</comment></comment><comment><USER8> "Is the primary sex ratio the same in all human populations at all times?" At least the secondary sex ratio naturally varies in human populations, being lowest in African's and somewhat higher in most others, see [0] and many other references.

Meiotic drive can effect which embryo's survive [1] & [2]. It's an intragenomic conflict where one copy of a gene is passed on to offspring more than the expected 50%.

[0] [http://www.cdc.gov/nchs/data/nvsr/nvsr53/nvsr53_20.pdf](http://www.cdc.gov/nchs/data/nvsr/nvsr53/nvsr53_20.pdf).

[1] [https://westhunt.wordpress.com/2015/04/09/a-common- variant-l...](https://westhunt.wordpress.com/2015/04/09/a-common-variant- linked-to-chromosomal-errors/)

[2] [http://www.unz.com/gnxp/human-uniqueness-is-not- unique/](http://www.unz.com/gnxp/human-uniqueness-is-not-unique/)

</comment><comment><USER9> I see a problem. They use data from in vitro fertilization to conclude the primary ratio is about 100. That's neglecting a part of the natural process that could introduce a bias. While earlier on the author rejects a couple of measurements due to their mutual inconsistency - even though they were both above 100.

</comment><comment><USER10> I would say the ratio of boys to girls at the moment of conception is practically always 1:1?

<comment><USER11> The entire point of the article is that it isn't that clear.

<comment><USER12> No, the article is very clear that the ratio at conception is exactly 1:1 (or incredibly close to it).</comment></comment></comment>


Ask HN: Hackernews-like site for the Enterprise IT space? - <AUTHOR>

I love HN and the discussions that ensue. Is there a similar site (or good site, at least) for tech innovators in the enterprise? <comment><USER2> Is there anything your looking for specifically that would talk about specific topics?</comment>