Moons of all the planets in our solar system - <AUTHOR> https://www.go-astronomy.com/planets/planet-moons.htm <comment><USER2> I'm surprised we haven't seen more hard sci-fi in the jovian or cronian systems. While constant 1g acceleration drives open the whole solar system to the ~month travel time that benefits stories, much more realistic accelerations (or limited fuel) can still manage the same within those systems. Add to that the plethora of interesting moons, rings, and gravitational points to focus people and material around and the action should flow quite naturally.

See The Expanse Season 2 (it's _amazing_ ).

<comment><USER3> The books are great and the TV series is now on Amazon Prime, with future seasons coming. Anybody on HN ought to be watching it.

<comment><USER4> _... the TV series is now on Amazon Prime, with future seasons coming._

Fortunately Amazon took it. If after three seasons of slow development it ended where we start to see answers, I would have considered it a scam. Not so insulting as Gallactica, but definitely annoying.

</comment></comment></comment><comment><USER5> There is a comment on the site that the Galilean Moons of Jupiter can be seen with the naked eye under dark skies. I've known people who might have eyes good enough to do that, but for the rest of us even a modest pair of binoculars is enough. To me, it's one of the funnest things you can view in the northern hemisphere without getting out more serious equipment. (Another would be the Orion nebula. If you can set the exposure on your camera, you can even photograph it, although without tracking it'll be blurry.)

<comment><USER6> Wasn't Galileo first to observe them with his telescope or were they mentioned somewhere before? I assume back then the skies were darker and people probably had better eyes so if they are observable I would assume somebody would have mentioned them.

<comment><USER5> There are a few confounding factors:

1\. Jupiter is very bright.

2\. The moons aren't always visible (they're behind or crossing Jupiter).

3\. The magnitude of the moons changes with the relative positions of Earth and Jupiter.

It's possible that Galileo was not the first to see them, but if you don't know what they are or how you managed to see them, you're probably not going to be able to get anyone else to believe you. The telescope allowed Galileo to track their movement and also to convince others, who could also look through a telescope and see them easily.

</comment></comment></comment><comment><USER7> If you want to play with this data, it's available in various formats [1]

I happened to use this last week because we needed test data for a community tree in an app we're building. There are nine communities, and we needed test cases with 0, 1, and many subcommunities. This not only provided ready test cases, but the team is learning celestial facts while working on the feature!

[1] [https://devstronomy.com/#/datasets](https://devstronomy.com/#/datasets)

</comment><comment><USER8> Very nice summary of the moons. I showed it to my kids.

Though I was surprised to find a scientific astronomy related page using inches and Fahrenheit units.

Though I guess the target audience it has been made for is perhaps US based school kids, but the page works really well for anyone across the world.

</comment><comment><USER9> It's interesting to note that there is no well-defined lower limit on the size of what can be called a moon. So I can call a dust particle a moon as well.

</comment><comment><USER10> Whenever people say they were born too late to explore the earth or too young to explore space i dont understand it. Something like 90% of the objects in our solar system have been discovered in the last ~15 years. There's tons more out there. Sure the major planets and their moons are here, but you scroll to the bottom of this list there's unconfirmed dwarf planets. And likely moons of them as well

<comment><USER11> The last trip to Pluto reminded me of being a kid again, when I pored over the newspaper looking at Voyager's trips to the gas giants.

</comment></comment><comment><USER12> Is any of the moons in solar system having smaller moons orbiting them?

<comment><USER13> While not exactly the sub-moon you're looking for there are some interesting objects that come close.

Co-orbital moons, like Saturn's Janus and Epimetheus, are moons that are in stable orbit-swapping configurations. [https://en.wikipedia.org/wiki/Co- orbital_configuration#Co-or...](https://en.wikipedia.org/wiki/Co- orbital_configuration#Co-orbital_moons)

Then you've got asteroids that are contact binaries that also have moons, like 216 Kleopatra. [https://en.wikipedia.org/wiki/216_Kleopatra](https://en.wikipedia.org/wiki/216_Kleopatra)

And finally, you have 624 Hektor, which is a Trojan of Jupiter (stable solar orbit near Jupiter's L4 Lagrange point), that is a a likely contact binary that has a moon. So it's orbiting the Sun, while "orbiting" Jupiter's L4 point, while all 3 components (the two halves of the contact binary, and their moon) orbit the center of mass of their own little 'Hector system'. [https://en.wikipedia.org/wiki/624_Hektor](https://en.wikipedia.org/wiki/624_Hektor)

</comment></comment><comment><USER14> Is there a CSV somewhere?

<comment><USER15> _Devstronomy project aims to provide datasets related to astronomy in an accessible format (CSV, JSON, SQL)._

[https://devstronomy.com/#/datasets#csv](https://devstronomy.com/#/datasets#csv)</comment></comment>


Standard deviation is ready for retirement: Nassim Taleb (2014) - <AUTHOR> https://www.edge.org/response-detail/25401 <comment><USER2> Great writeup. I think this should go hand in hand with articles explaining why p <= 0.05 is not an end-all be-all confirmation of your hypotheses/conclusions. Before I jumped to the software engineering world, I did biostats and was essentially a "bioinformatician". You quickly realize how many experts in the field misuse statistical tools entirely while using their results to prove a point, or worse, draw conclusions incorrectly from their results. A big faux pas I saw a lot was using normality-assumed parametric tests on non-normal data where the skew was clearly significant (i.e. you couldn't get away with it like some non-normal data dists.). Seriously, go take a look at some bioinfo papers (or any biology papers for that matter), it's getting pretty bad. However when we learn (even in master's or Ph.D. programs) about these mathematical tools, we are not often taught about what the math means. I'm sure I'm not the only one to have been taught formulas as a means to prove your research rather than the theory/intuition behind them. Luckily there are articles such as these that force you to step back and consult the maths again to learn what is really going on.

As an aside, I'm sure this sort of thing happens in all walks of life, not just maths/data science. Some programmers don't understand the intuition of certain things that they code and when it is time to explain they will likely freeze because they know how to code it, but don't really know why the code works fundamentally.

<comment><USER3> > A big faux pas I saw a lot was using normality-assumed parametric tests on > non-normal data where the skew was clearly significant (i.e. you couldn't > get away with it like some non-normal data dists.)

Depends on how much data you have. With a couple hundred observations, you can have as much skew as you like and the normal approximation will still be pretty good. I only mention this because there are a lot of misconceptions about how statistics relies on normal data, when really it mostly just relies on the distribution of the mean being normal, which is pretty much a given because of the central limit theorem. There are much worse sins and abuses -- which yes, unfortunately you do see all the time in scientific papers.

<comment><USER4> In general it is a misconception that real data always follows a normal distribution. It is true that if you sum many /independent/ random quantities, then the result is approximately normal (e.g., the central limit theorem and generalizations). But real data tends not to be independent. Many real world quantities follow extremely skewed distributions. E.g, Zipf's law, Korcak's law, Pareto's laws.

For a concrete example, if you look at the distribution of the number of friends users have on social networks, you might expect that 95% of people have the mean number of friends +/\- a few standard deviations (since this would be the case for a normal distribution). It would be virtually impossible for someone with a number of friends that is say thousands of standard deviations away to exist, yet there will be many such users in social networks (celebrities, bot networks, etc). In reality, the empirical distribution in this case follows an extremely skewed distribution.

<comment><USER3> And yet a Pareto distribution still has a mean, and the sampling distribution of that mean is approximately normally distributed.

Of course I'm not claiming that you can just pretend that a Pareto distribution is a normal distribution, but statistical tests are generally concerned with differences in means (group A does on average 25% better than group B) so it's the sampling distribution we're interested in, not the parent distribution.

You make a good point about autocorrelation and dependent data, but that's a very different issue. To riff on your example about social networks, you'd have dependent data if you're trying to see what kind of news articles people like to read, if those preferences turn out to be mostly guided by what friends are reading.

<comment><USER5> "And yet a Pareto distribution still has a mean, and the sampling distribution of that mean is approximately normally distributed."

This is often wrong. The central limit theorem requires finite variance and some (yet common) Pareto distributions have infinite variance.

</comment></comment></comment></comment></comment><comment><USER6> I confess that I found this article unhelpful. There are interesting tidbits in there, but I don't think it helped me identify any specific errors you'd reach by using a standard deviation rather than mean average deviation. The closest it came was:

"1) MAD is more accurate in sample measurements, and less volatile than STD since it is a natural weight whereas standard deviation uses the observation itself as its own weight, imparting large weights to large observations, thus overweighing tail events."

More accurate how? Less volatile, not overweighing tail events: what inference would I make incorrectly by using the standard deviation?

To be clear, I'm not arguing "for" standard deviation, I'm just saying that I wish this article had said more about why it's potentially misleading/less powerful.

<comment><USER7> > specific errors you'd reach by using a standard deviation

> ..."overweighing tail events."

That's it. Sigma puts too much weight on outliers, giving them the power to distort summary stats. MAD doesn't.

<comment><USER8> I don't think that answer helps. How are you assigning "too much" weight on outliers, and the process behind deciding the right amount of weight? Can you think of any concrete examples?

<comment><USER9> In this case what Taleb is concerned with is decision making. The right amount of weight is what allows human beings to make good decisions. He believes that MAD is much more intuitive to humans and therefore leads to better decisions.

<comment><USER8> In that case, I'm looking for a concrete example.

</comment></comment></comment></comment></comment><comment><USER10> I met Nassim Taleb a few years ago. He was doing due diligence on a fund I was working at.

He's an incredibly colourful character. We chatted about various authors in the statistical space, and chastised them all! "What about (this guy)? Idiot!" It was a rant worthy of a Hitler parody. "Everyone who believes in standard deviation, leave the room!"

It was hilarious. He had a point, too, about our statistical methods. A few months later the fund blew up in a textbook way. He'd have made a packet if he followed his own advice. No idea if he did.

<comment><USER11> "Everyone who believes in standard deviation (...)"

Sounds like a moron.

I would love to hear more about what happened with your fund though.

</comment></comment><comment><USER12> _" What is worse, Goldstein and I found that a high number of data scientists (many with PhDs) also get confused in real life."_

Wow. Just wow.

Some of people are calling themselves "Data Scientists" who don't know the difference between σ and MAD?

I don't care how many letters are after your name. If you don't know the absolute most basic types of summary statistics, you have no business calling yourself a Data Scientist.

\---

To the phonies, please stop. Most of us work _hard_ to stay at the bleeding edge, lest we fall behind, as I'm sure all HN devs strive to do. You're essentially defrauding people, and if you're working on anything important, the cascading effects can hurt a lot of real live actual human beings.

It's one thing to play around with data science to satiate your curiosity. It's an entirely different matter to declare it your profession. For example, I play around with KSP. That does not make me an Aerospace Engineer.

\---

Edit in reply @tgb: Actually I think you and I are on the same page about what Taleb means. In fact, MAD is probably the more intuitive summary statistic for most people.

I just find the number amongst Data Scientists surprisingly high, since half the job is spotting these kinds of misinterpretations.

<comment><USER13> Even worse there are people (utter frauds of course) who confuse MAD and MAD! In all seriousness, there is much confusion between Median Absolute Deviation and Mean Absolute Deviation out there. Ironically the MAD in this article is still not a robust measure of variation in data as it will break for the many distributions that have undefined/infinite mean (Cauchy and Levy as examples).

Even then many summary statistics rely on a well-defined PDF which is also not true for many real life cases. I think most data scientists out there are very familiar with quantiles, which are often more useful as all random variables have a CDF (and the quantile is just the inverse CDF).

I quite enjoy Taleb's writing (I tend to find his ego a bit amusing) but I think even he is guilty of Jaynes' "Mind Projection Fallacy"[0] in regards searching for more meaning than exists in Fat-tailed distributions. When we model our data with infinite/undefined mean and variance distributions we're just saying "I don't know". No amount of cleverness with summary statistics, or understanding of pathological distributions will create information where there is none.

The overall point being: there are many, many ways of viewing statistics and it's pretty trivial to find a perspective that allows you to call someone a "fraud". Sure there are actual frauds in data science, but one of the biggest strengths in this trend is bringing quantitative people from a wide range of backgrounds to gain refreshing insights. It is much more useful to encourage cross-discipline exploration than to simply say "you don't belong here".

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

<comment><USER14> Doesn't seem like he's seeing more meaning than exists, check this book out & this field.

[http://www.amazon.com/Modelling-Extremal-Events- Stochastic-P...](http://www.amazon.com/Modelling-Extremal-Events-Stochastic- Probability/dp/3540609318)

[https://fernandonogueiracosta.files.wordpress.com/2014/07/ta...](https://fernandonogueiracosta.files.wordpress.com/2014/07/taleb- nassim-silent-risk.pdf)

Also Jaynes, made the mistake of thinking only Guassian's matter(The mistake he criticizes).

</comment></comment></comment><comment><AUTHOR> I submitted this for Nassim's article but this whole site is pretty great. Check out their "big questions" on the left hand side where they get people to weigh in on them:

[https://www.edge.org/contributors/what-do-you-think-about- ma...](https://www.edge.org/contributors/what-do-you-think-about-machines- that-think)

[https://www.edge.org/contributors/what-scientific-idea-is- re...](https://www.edge.org/contributors/what-scientific-idea-is-ready-for- retirement)

[https://www.edge.org/contributors/what-should-we-be- worried-...](https://www.edge.org/contributors/what-should-we-be-worried- about)

[https://www.edge.org/contributors/what-is-your-favorite- deep...](https://www.edge.org/contributors/what-is-your-favorite-deep-elegant- or-beautiful-explanation)

And to be honest where else can you find Nassim Taleb weigh in on any subject but keep himself to writing only 500 words:)

</comment><comment><USER15> There are some reasons to prefer variance/stddev, such as getting averages correct: [http://www.win-vector.com/blog/2014/01/use-standard- deviatio...](http://www.win-vector.com/blog/2014/01/use-standard-deviation- not-mad-about-mad/)

<comment><USER3> That's not a valid reason. You use descriptive statistics when you describe something and you use inferential statistics when you're doing inference.

<comment><USER15> I understand we disagree, so I'll try to clarify my point of view a bit which hopefully makes things better not worse.

One often (despite promises not to) is forced to optimize what one measures or shares. It may or may not be relevant to a particular project, but I doubt it is completely invalid (despite the claimed clean room separation of descriptive and inferential procedures).

The idea is: if one believes absolute deviation is the one true measure then it would not make sense to optimize over a different measure (variance).

I in fact like quantile regression, but it has its own caveats.

<comment><USER3> So, let's say we want to make an industrial process more reliable by reducing the variability of its output. We repeatedly measure the variability by means of MAD. We'd like to know what causes the variability, so we regress MAD on various predictors to see what causes variable performance. The regression allows us to optimize MAD but the regression itself is fit using ordinary least squares. I don't think anyone would object to that?

I guess you're thinking more along the lines of describing the performance of a model in terms of the MAD, and then optimizing using MAD / L1, which isn't always a wise choice? Then I guess we don't disagree at all. I do like MAD as an easy to communicate loss statistic in many cases (as well as % of cases with predictions further than a domain specific distance from the truth), but I don't think many people would consider loss to be a descriptive statistic at all – it describes not the world but a model of the world.

</comment></comment></comment></comment><comment><USER16> This is silly in my view, and bordering on pseudoscience-level writing. It's not a random historical accident that we use these quantities.

Variance / stdev appear all over probability and statistics. For example, in this famous Stats 101 theorem: [https://en.wikipedia.org/wiki/Chebyshev%27s_inequality](https://en.wikipedia.org/wiki/Chebyshev%27s_inequality)

<comment><USER17> You are mistaking him for someone who is ignorant and slagging the best practices; in fact, he's incredibly knowledgeable and experienced and slagging best practices. I'm not saying he's guaranteed to be right about everything, but he's made rather a lot of money by turning his criticisms into actions, and that's a pretty tall bar to leap.

I'll say it again because I can already hear the reply buttons clicking... I'm _not_ saying he's right about everything or that money is the only measure of rightness. I'm just saying that it's definitely a measure worth paying attention to, and definitely puts you on the experienced side rather than the ignorant side. If it was just chance, it's still interesting.

<comment><USER16> Sounds like Appeal to Authority to me: [https://en.wikipedia.org/wiki/Argument_from_authority](https://en.wikipedia.org/wiki/Argument_from_authority)

FWIW I am also someone who knows what he's talking about, as I am a seasoned professional in the same line of work.

This guy's accomplishments don't make the Chebyshev inequality any less true (nor all the other theorems involving variance), so I don't see how he can claim something like this and be taken seriously by people in the field.

<comment><USER17> Because it's not about the theorems being wrong, it's about people using them in impractical ways.

The Central Limit Theorem is true. Full stop. It can't be wrong. However, in the real world, a lot fewer things are truly Gaussian than may initially meet the eye. It doesn't make the CLT "false", it just means that people who apply it too carelessly are making a mistake. Standard deviation is a thing, but that doesn't make it the _right_ thing for a given task.

A lot of people apply statistics inappropriately. It's hardly their fault, it's basically what they are taught. I remember seeing my wife take her biology statistics courses, which at times seemed to be a course in which you would repeatedly calculate p-values. Just that, over and over; calculate this p-value. Calculate that p-value. Calculate this other p-value. Say "Yes" if it's less than 0.05 and "No" if it's greater. Now do it again. And again. And again. Certainly numbers went in one end of the calculator and came out the other, but did they _mean_ anything? If not, it's not because the p-value isn't "true", just not even remotely as useful as the course was implicitly teaching.

(Yes, _words_ were said about how it wasn't the only useful thing, but the actions spoke loud and clear. Compute p-value. Say yes if below 0.05. Say no if above. Repeat. The current problems all the fields are having with statistics aren't that surprising if you look back to the beginning.)

</comment></comment></comment></comment><comment><USER18> I remember that when I learnt Probability Theory at Uni around 1996, I got a 3- in the exams (german grades go from 6 (the worst) to 1 (the best), a - indicating a tendency towards the worse grade, and + indicating a tendency towards the better grade). Everyone else in that year got a worse grade ... And we were all (aspiring) mathematicians. The thing is, if you want to teach that stuff in a way that is both rigorous with respect to theoretical underpinnings, while at the same time making sure that the student can actually apply in practice what they learnt ... that's a pretty difficult task, even if your students are all mathematicians. Now, I have no idea what a good way to teach these things to non-mathematicians would be!

Edit: I always was quite astonished of how easily Biologists etc. seem to have understood quite complicated probabilistic mathematics, but now I understand that mostly they are just cargo culting stuff they don't really understand.

</comment><comment><USER19> I have replaced uses of the Standard Deviation with the Mean Absolute Deviation at work on several occasions, for just the reasons described here. It often leads to substantial improvement in predictive validity, in some cases fixing a broken process.

<comment><USER20> What kind of processes are we talking about?

</comment></comment><comment><USER21> Might be a little premature to call for retirement of sigma. The mathematical concept of standard deviation is super useful but I agree that the name is confusing and that we need to improve the naming and ideally the notation and teaching of statistics. Ability to deal with uncertainty and variance is becoming more and more important in all sorts of fields as data volumes get larger so I'd hate to see us give up just because it is hard to understand.

<comment><USER22> I've never really been a fan of the notation. But I don't know how you can conceivably enforce this because just like programming, people will pontificate about 'design', 'clean code', 'maintanability' and other similar cargo-cult buzzwords but they will go ahead and do whatever they want with their code.

<comment><USER21> Completely agree that standardizing notation takes decades as a lot of it is how textbooks and tutorials from experts are written. I for one though am really glad that we standardized on Leibniz's notation rather than Newton's for calculus though and aren't using roman numerals anymore.

</comment></comment></comment><comment><USER23> The technical (real article) is here; [https://dl.dropboxusercontent.com/u/50282823/standarddev.pdf](https://dl.dropboxusercontent.com/u/50282823/standarddev.pdf)

</comment><comment><USER24> Previous discussion about Taleb's view on this: [https://news.ycombinator.com/item?id=7064435](https://news.ycombinator.com/item?id=7064435)

</comment><comment><USER25> Using MAD instead of standard deviation in the formula for correlation would result in the possibility of random values being "correlated" by values that exceed 1 in magnitude (the proof for a correlation coefficient being bounded by 1 relies on the Cauchy-Schwarz inequality, which could no longer be appealed to).

This doesn't detract from Taleb's points at all, but it does show a mathematically "nice" property that results in the usage of standard deviations.

[1] [https://en.wikipedia.org/wiki/Cauchy%E2%80%93Schwarz_inequal...](https://en.wikipedia.org/wiki/Cauchy%E2%80%93Schwarz_inequality#Probability_theory)

</comment><comment><USER26> I usually prefer median absolute deviation on real world data. It's more robust than either SD or mean absolute deviation.

</comment><comment><USER27> Where can I read more about the concept of infinite variance?

A gentle introduction would be much appreciated.

<comment><USER28> [https://en.m.wikipedia.org/wiki/Cauchy_distribution](https://en.m.wikipedia.org/wiki/Cauchy_distribution)

<comment><USER27> Thanks! How does this relate to real-world statistics? In what context(s) does this pop up?

Edit: what's wrong with my question? I _did_ mention a gentle introduction was needed, so if the answer is obvious to some, please forgive my ignorance and help me fix it.

<comment><USER29> Imagine an infinite line and a spinner[1] a short distance away from it. Spin the spinner, wait for it to stop, and then mark the point on the line that the spinner is point directly at (or away from). Repeat lots of times. The resulting points have a Cauchy distribution. If you tried to figure out where the spinner was along the line by taking the arithmetic mean of the points, you would fail miserably. Taking the median is much more likely to give you a good answer.

That was still a somewhat contrived example to demonstrate the point, but if you replace the spinner's pointing with photons, you realize that a Cauchy distribution describes the intensity of light shining on a flat surface from a point light source[2].

[1] That is, one of these things: [http://www.ontrack- media.net/math8/m8m5l1image13.jpg](http://www.ontrack- media.net/math8/m8m5l1image13.jpg)

[2] [http://stats.stackexchange.com/a/36037/5736](http://stats.stackexchange.com/a/36037/5736)

</comment></comment></comment></comment><comment><USER30> If we regard taking the absolute value as a squaring followed by taking the positive square root, then basically we have "root mean square" (STD) versus "root square mean" (MAD), that is all. The one calculation takes the square root _after_ the mean, the other moves it _before_.

If we extend MAD to vectors, then we average the vector norms.

What is the norm? It is the root mean square of the vector components. So then MAD is then the "root square mean" of "root mean squares".

</comment><comment><USER31> The difference between MAD and STD is the use of the mean instead of the quadratic mean. Sometimes the quadratic mean is better, for example: if you have n some particles with velocity vi then the quadratic mean allows you to replace your system with another where each particle has the same velocity, the quadratic mean, this way the total kinetic energy is the same as in the original system, and this conservation of energy is a very important property in physics.

</comment><comment><USER32> To understand better. Lets take the following deviations from mean in series A&B.

A: 2, 1, 3, 1, 2

B: 4, 1, 2, 1, 1

MAD(A) = 9/5 = 1.8

STD(A) = sqrt(21/5) = sqrt(4.2) = 2.05

MAD(B) = 9/5 = 1.8

STD(B) = sqrt(23/5) = 2.14

So it clearly shows that STD penalizes any significant error. It weights any deviation by itself (Sqare). So the message is all the values in a series should be in a close range. If you look at its applications.

[https://en.wikipedia.org/wiki/Standard_deviation#Interpretat...](https://en.wikipedia.org/wiki/Standard_deviation#Interpretation_and_application)

"a small standard deviation indicates that they are clustered closely around the mean"

The answers in this stack exchange (regarding RMSE, same thing, as Taleb also notes), also point to this: [http://stats.stackexchange.com/questions/118/why- square-the-...](http://stats.stackexchange.com/questions/118/why-square-the- difference-instead-of-taking-the-absolute-value-in-standard-devia)

Also as per this wiki, its mainly used to compare models against each other: [https://en.wikipedia.org/wiki/Root-mean- square_deviation#App...](https://en.wikipedia.org/wiki/Root-mean- square_deviation#Applications)

One comment on HN says that its M is for Median in MAD. Taleb's note itself makes it clear by the temperature example that it is Mean average deviation.

Also, whats with the Taleb bashing on HN in these past two articles. The man may be arrogant or he may be not. So what? Bringing that aspect of someone's personality in technical discussions is bringing them to a very low level, apart from being Ad hominem. I think, even in this post he is speaking from a point of view of a practitioner, who has seen a tool abused a lot. And he may not have all the time to utter out his full knowledge about a subject. Just by that mention of Karl Pearson, it is obvious he knows compeletly what he is talking about, as that person seems to be the first who gave the term 'standard deviation' to 'root mean square error (As per wiki on STD).

</comment><comment><USER33> A similar thing is using least squares for linear regression rather than minimizing MAD. In past the argument was that the least squares sum has a closed expression, but with computers even that advantage eliminated.

The nice thing about minimizing MAD is that in typical settings the liner regression line-plane-hyperplane goes through measurement points. As such there is no interpolation and outliers are nicely cut off making the result very robust to measurements errors.

</comment><comment><USER7> One of the barriers to adopting MAD() is the two passes over a dataset needed to compute it.

As it happens, I made a MySQL feature request for a MAD() aggregate function when Dr. Taleb's article first appeared. Any upvotes on that request would be welcome.

[http://bugs.mysql.com/bug.php?id=71391](http://bugs.mysql.com/bug.php?id=71391)

</comment><comment><USER34> I think that linck should be here: [http://www.win- vector.com/blog/2014/01/use-standard-deviatio...](http://www.win- vector.com/blog/2014/01/use-standard-deviation-not-mad-about-mad/)

</comment><comment><USER23> [https://dl.dropboxusercontent.com/u/50282823/standarddev.pdf](https://dl.dropboxusercontent.com/u/50282823/standarddev.pdf)

</comment><comment><USER35> While we're at it, can we also retire "linear" mean in favour of geometric mean in what is commonly understood as "average"?

It is far more representative in most real life situations I find.

<comment><USER36> Can you give some examples where it's more representative? Average height? Average income? There are a lot of arguments in favor of median as a more intuitive replacement (and it is frequently used thus) but consider that:

a) Some people have ZERO income. b) Either an odd or even number of people have NEGATIVE income.

Every day I deal in execution times, rounded to the nearest integral number of milliseconds. Lots of zeros.

A measure that is (a) not actually intuitively correct, (b) very hard to calculate in your head, and (c) useless for many, many non-trivial cases is NOT a good replacement for "linear mean" which is (a) often intuitively correct, (b) pretty easy to calculate in your head, and (c) always works, seems better.

<comment><USER37> Geometric mean also interacts with unit conversions which use a different zero-point. For instance, if you take the geometric mean of daily temperatures, you will get different means depending on whether you work in F or C or K.

</comment></comment></comment><comment><USER38> I never understood why "root mean square deviation" is called standard deviation instead of the MAD. That always annoyed me.

</comment><comment><USER39> It'll be good to see MBAs bragging about their "6 MAD" courses instead of their "6 Sigma" ones...

</comment><comment><USER40> I'm rather surprised how exceptionally naive articles are upvoted on HN when the subject matter is specialized. If you're going to talk about retiring standard deviation you should have some pretty detailed mathematical arguments, this is a waste of time.

<comment><USER41> You didn't read it? Or you overlooked the part where he said WHO should "retire" it - and who should keep it!

This is about how people _interpret_ statistical results. Which is not a mathematical process - it is what comes _after_ the math.

<comment><USER40> > This is about how people interpret statistical results. Which is not a > mathematical process - it is what comes after the math.

If the later is not a process with a scientific method which can be detailed and substantiated, than this is mysticism and my interest stops there.

That being said you really don't need to do math to practice mysticism, but I'm sure having numbers and equations help with the hand-waving when selling it to non-technical people.

</comment></comment></comment><comment><USER42> Taleb is partly correct in his

> Standard deviation, STD, should be left to mathematicians, physicists and > mathematical statisticians deriving limit theorems.

E.g., for positive integer n and a sequence of n random variables with the same expectation and with finite variance and, as n grows to infinity, with the variance converging to zero, the random variables, actually points in the Hilbert space commonly called L^2, converge in the norm of that space, and then a subsequence must converge almost surely, that is, the strongest case of convergence. Of course, this is a very old result and standard when consider convergence of random variables.

But standard deviation still has an important role in common applications of statistics without "deriving limit theorems". And, with some irony, we don't derive a limit theorem but use one, indeed, likely the most important one, the central limit theorem (CLT).

With the CLT, under mild assumptions, for positive integer n, as n grows to infinity, the probability distribution of the mean of n independent and identically distributed (the _i.i.d._ case) converges to a Gaussian. Likely the mildest assumptions are from the Lindeberg-Feller case (don't ask but look it up if you wish, and to read the proof set aside much of an afternoon).

Now, when have convergence to a Gaussian and have the standard deviation of that Gaussian, we can calculate any and all confidence intervals we want on our estimate of the mean of that Gaussian. So, THAT'S one case of where and why even in just common work we still want standard deviation.

Yes, how fast the convergence is to a Gaussian can be relevant in protecting against Talib's "black swans" and avoiding, say, the disaster of Long Term Capital Management (LTCM) in their estimates of _volatility_.

That is, suppose we want to estimate the standard deviation of an average (as above). Suppose the random variables we are averaging have a distribution that has in its probability density function a bump way, way, way out in a tail. The way out in the tail means that if get such a value, then it's really large (in absolute value, and in practice really far from the expectation of that random variable). So, if get a value in that bump, then can have a "black swan". But the probability of the bump is quite small. So, we can take samples from the distribution of that random variable and average them for weeks before we ever get a sample from the bump, before ever see a _black swan_.

So, doing this, in our sampling never seeing a black swan, we can have an estimate of standard deviation that is significantly too small. So, with that small standard deviation, can believe that some highly leveraged financial positions are relatively safe, that is, also have low volatility.

Then, bad day, the Russians default on something, we get a "black swan", and suddenly lose some billions of dollars where before we were really sure that wouldn't happen for millennia. Sorry 'bout that.

Roughly, that is what happened in the famous, expensive crash of LTCM.

</comment><comment><USER43> What he says seems to supply to volatility, but does it apply to other uses of volatility?

</comment><comment><USER44> I don't find "nassim" anywhere on the page or in the source.

<comment><USER45> It looks like they're expecting you to click through from this page: [https://www.edge.org/contributors/what-scientific-idea-is- re...](https://www.edge.org/contributors/what-scientific-idea-is-ready-for- retirement), which lists the actual authors.</comment></comment>


Uber accounts for less than 0.1% of economy's total work hours and compensation - <AUTHOR> https://www.epi.org/press/uber-drivers-earn-the-equivalent-of-9-21-in-hourly-wages-uber-and-other-gig-platforms-account-for-far-less-of-the-economy-than-many-estimates-suggest/ <comment><USER2> mr money mustache calculated it at only $6/hour</comment>


Discovery of a New Retrograde Trans-Neptunian Object - <AUTHOR> http://arxiv.org/abs/1608.01808 <comment><USER2> Everything's "trans" these days.</comment>


When Steve Jobs isn't happy, he really isn't happy - <AUTHOR> http://news.cnet.com/8301-17852_3-20060802-71.html <comment><USER2> That's been Steve's managerial style since he started Apple. I'm worried that once he is no longer able to come back(I think the current medical leave is temporary) that Apple will become a "good enough" company. People tolerate Steve berating them because of his charisma and I am not sure that Tim Cook will be able to get away with what Steve can.

<comment><USER3> _People tolerate Steve berating them because of his charisma_

Or fear, or something, but the charismatic people I've come to know don't berate people. They don't have to.

</comment></comment><comment><USER4> IMO it is essential for Jobs to do that in order to demand high quality and perfection. It is better to say things like that in the face of people rather than to smoothen the communication and then let them go or move them to different projects without explaining why. I would absolutely do the same thing in his shoes. It is the fastest possible way to get the message across. Now, this may be unpleasant and he may indeed show some lack of balance of temper but it may very well be on purpose. This is of course speculation on my part since I haven't met the guy and I have not worked for Apple.

<comment><USER5> I would agree but lots of Steve-wannabe CEOs adopt the cargo cult and think that being belligerent is key to getting stuff done.

This is exactly not the case. Steve gets away with it because he's maniacally focused on improving Apple.

It's not that he gets annoyed and spouts expletives, but WHY he does it, and FOR WHAT REASON.

<comment><USER4> Maniacal focus is assumed here. We're not even discussing doing things casually.

</comment></comment></comment><comment><USER6> When I read what Jobs' is reported to have said my first thought was the song Stan by Eminem. I don't know why but the tone just struck me a very similar.</comment>


Focusmate – Virtual Coworking Helps You Get Things Done - <AUTHOR> https://www.focusmate.com/ <comment><USER2> I've been using focusmate for four months. It's been absolutely revolutionary for me. (I work remote at home, so YMMV.)

Here are some of the ways:

(1) I've been getting a ton more done and feeling better about it.

(2) It really does help me focus. I hardly ever get distracted from the task at hand. I used to get distracted a lot.

The focus does not come from being watched, but because I'm "working together" with someone else, and I don't want to let them or myself down. And because of the built-in break/recovery schedule. It's like a hack for my brain.

(3) I schedule back-to-back sessions, so I have 50 minutes of 100% focus and then 10 minutes between. In the 10 minutes I use the bathroom, get coffee, clear my head, walk around, or stretch. These things I'm sure help enable the 100% focus for the 50 minutes. I don't feel as worn out at the end of the day (and I get more done).

(3) Declaring my goal for the session at the beginning and then reporting on it at the end has caused me to become much more realistic about how long things take.

(4) Being more realistic about how long things take has made it possible to plan out my week. I'm now planning my day and week in "focusmate session sized blocks" of work. I do have to adjust the plan, but making the plan has been a huge help.

(5) Setting a focusmate appointment in the morning causes me me to get started at a constant time — for the first time in my life. Knowing that someone else is relying on me to be at the session makes me show up.

(6) The little bit of social connection helps working at home to not feel lonley.

<comment><USER3> It's like the Pomodoro technique, but with peer pressure of the Pomodoro timer being disappointed if you bail. Not wanting to let someone else down, even a stranger, I can see how that would help you stick to it. Brilliant!

<comment><USER2> You're right! Most of what I described is common to the Pomodoro technique. I was never able to stick to the Pomodoro technique. The accountability of the timer being a person is huge.

It's weird (but true) that disappointing a random person is more motivating to me than doing what I told myself I would do.

</comment></comment></comment><comment><USER4> Been using this for the past 4-5 months, ever since I saw a personal story of someone using it posted to HN.

It's been a game changer for me. I can WFH productively for the first time in my life, and have had 95% enjoyable experiences with the people on the other end of the chats thus far.

To those complaining about the pricing...they just started charging and I'm sure that's why it's not in the FAQ. Also, it's $5/mo, they aren't trying to get you hooked on something and then surprise you with $500/mo or something.

</comment><comment><USER5> I used Focusmate a lot and then dropped it. I think it serves its purpose well until you get used to it and then productivity starts dropping again.

I also would like to highlight something which is not particular to Focusmate but rather a phenomena spreading to all these SaaS platforms: Focusmate is not free. It's a paying product that costs $5/month.

There is absolutely no details of pricing on the home page. There is no pricing page on the website. The FAQ itself doesn't mention pricing. This will only come up after you signup and start using it. There are details on the blog but that's about it.

It really gets on my nerves when services do that and I decided to ignore anything that ignores my right to know the price beforehand. But I can see it working with the general public for a while.

<comment><USER6> Founder of Focusmate here.

I'm sorry to hear the effect that not having a pricing page has had on you. Thanks for sharing your feedback.

A few thoughts:

1) Focusmate IS free to use 3 times per week. Most of our users are on the free plan. You can use it in perpetuity for free.

2) We don't have a pricing page yet because we started charging 29 days ago, and because we're shipping product incrementally. (We are a 3-person team with 1 engineer, FWIW.)

3) At this very nascent stage, there is value to being able to run pricing tests, which we can't do if we publish a pricing page. (The downside is we annoy some people, which is not a trivial downside. Knowing the negative effect on you is meaningful to us/me.)

I welcome additional thoughts/feedback.

Taylor

<comment><USER5> > Focusmate IS free to use 3 times per week.

Better say that Focusmate is free to try. 3 times/week is so little to be any useful.

<comment><USER7> > 3 times/week is so little to be any useful.

If a user is exceeding this free teir, they're likely finding it useful enough to pay, and should pay

</comment></comment></comment></comment><comment><USER8> There seems to be various unrelated domains that are tapping into the power of _virtual presence of others_ to enhance personal performance.

The obvious one is the Peloton exercise bikes with the video of the live instructor motivating them.

Before the virtually connected humans, we had real ones such as "pacers" in running: [https://livehealthy.chron.com/pacer- running-2865.html](https://livehealthy.chron.com/pacer-running-2865.html)

There's probably a meme or jargon that encompasses all the above psychology but I don't know what it is.

</comment><comment><USER9> I hate it when services have texts like "get started for FREE". What does that mean? Is literally just the signup for free? Do I have to pay some subscription in the future? Is it a time limited trial? Is it really just free? ... oof.

</comment><comment><USER10> A similar product, that I think I found on HN actually, is [https://complice.co](https://complice.co) \- though it's more like you hang out in chat rooms with people doing pomodoros together combined with a GTD task manager. So, same sort of idea but less.. intrusive?

</comment><comment><USER11> I watched the 30 second video, and they mention that there is no collaboration (by design). Does anyone know of a site that does have collaboration?

My situation is that I'm getting back into contracting after being at an office job for 4 years. I'm updating my Upwork profile, getting my resume and portfolio together, all the things. But when I look at my recommended jobs, I get this sinking feeling like I'm working in a vacuum.

I'd prefer something that works line an online shared workspace, where I'd go in, say "hey I'm a backend PHP/Laravel and iOS/Android developer, does someone need help for a few hours or days for around 50 bucks an hour?" and someone would ping me with an offer and we'd get right to work solving their problem.

I also very much needed this when I couldn't find an answer on Stack Overflow. I've looked at [https://www.codementor.io](https://www.codementor.io) but can't tell if that's what they're going for or how much friction is involved.

</comment><comment><USER12> Video surveillance is not the solution to this problem. It's outright creepy. I think a simple chat group or a game can better serve the purpose of providing a virtual "office environment". I think highfidelity is working on something along those lines, but you can already use an opensimulator/secondlife space as realtime hangout place.

I'm also critical of their "behavioral triggers". For example, "Pre- commitment" has more often be found to have the reverse effect: when you tell people what you will do, you end up not doing it. And social pressure is hit or miss. (Their generic list of neurotransmitters is also suspect). I see a future in this but with a different structure: paid behavioral coaches that teach you how to be more disciplined. That would be a valuable service, because right now remote work is not for everyone for the reason that they 're not disciplined. That's something malleable

<comment><USER6> Is working at a coffee shop "surveillance"?

The experience on Focusmate is akin to working with a buddy at a library or cafe.

As far as pre-commitment: I think you've got your behavioral triggers mixed up.

Wikipedia has a good definition: "Precommitment refers to a strategy that an agent may use to restrict the number of choices available to him or her at a future time. The strategy may also involve the imposition of obstacles or additional costs to certain courses of action in advance."

I think you're thinking about telling someone what you'll do. That works when you tell someone what action you plan to take. It backfires when you share what result you'll get, because your brain visualizes some of the result, and experiences the reward prematurely.

<comment><USER12> > Is working at a coffee shop "surveillance"?

The security camera guy of the shop is surveillance. Being in a public space, knowing who is looking at you (let alone, he is being seen by others as looking at you), is not the same thing.

Maybe precommitment is not what i had in mind but but you do mention explicitly "implementation intentions" as "what to do and how you will do it" which may not be an optimal thing to do.

[https://www.psychologytoday.com/us/blog/ulterior- motives/200...](https://www.psychologytoday.com/us/blog/ulterior- motives/200905/if-you-want-succeed-don-t-tell-anyone)

</comment></comment></comment><comment><USER13> A couple of questions for experienced users, or FocusMate reps: this sounds like a potentially useful service but I'm concerned about privacy issues and not annoying other people, esp wrt working in public or common work spaces.

I guess this isn't much different to any other remote conference in that regard - any thoughts on how to use this in a polite and safe way? Or is the idea it's really for use in a private environment only, like your home? That is implied in some of the intro material.

Basically, what are etiquette considerations or issues for other people who aren't involved in the session? Just don't use it in that context?

Secondly, how have you handled the unusual nature of this compared to normal conferencing - where you are directly and continuously interacting with the other person, rather than having them quietly watching over your shoulder as in this case? There are obviously quite concerning potential privacy issues here as well.

<comment><USER6> Hi! Thanks for your questions.

We have many users who use it in public or semi-public places. You are only interacting with your Focusmate at the start and end, and that for just 30 seconds or so to say hello and share what you're committing to work on. As compared to people having a loud conversation in a cafe, this is very, very minimal. We also have users who are in libraries or other quiet spaces, and they usually indicate that on their profiles and by logging in early and sending a chat to their partner.

As far as the "unusual nature" \-- a few things. One, consider that it takes a fair bit of effort to set up and attend a Focusmate session. That screens out 99% of privacy concerns because people are truly motivated to be there to get work done. The fact that users have a profile and track record also mitigates this issue. Sure, we have new users joining, but once someone has 5-10 sessions under their belt, the community has had a chance to vet them. As far as new users with malicious intentions, that's certainly possible, and we have blocking and reporting functionality to stay on top of those issues. Last thing I'll add is that there isn't much someone can "do" to you over videoconference. If you were to feel uncomfortable, you can just close the tab.

You can learn more here: [https://www.focusmate.com/community](https://www.focusmate.com/community)

<comment><USER13> Much appreciated, thank you

</comment></comment></comment><comment><USER14> A few comments here saying this is creepy af. If you think that, fine, don't join. I think this is one of the most genius things I've ever come across, I love it, love the community and am so much more productive since I found it.

</comment><comment><USER15> No pricing info right now but it looks like it'd be fun to try out. As it's free that may help build up a user base.

<comment><USER16> Their turbo plan is $5 per month for unlimited sessions. Their free plan gives you 3 free sessions a week.

It's a bit weird that as a signed up user I can see the pricing information but it's not publicly available on their homepage. Anyway I like the service as 1 or 2 sessions in a day helps me get into the rhythm.

</comment></comment><comment><USER17> I love this idea, but I think there is a stronger pricing model than paying per session.

Is the founder on HN? Please talk to me - this is a large market that I've been keeping an eye on for a while. If this is executed with the right toolset, this could be a Zoom or a Slack one day.

<comment><USER18> If you sign up for FocusMate he'll email you ten times a day. You can also sign up to do a FocusMate session with him and then you'd be able to send him a message via the platform.

<comment><USER6> Taylor here. I welcome your feedback on how we do email campaigns.

<comment><USER18> I appreciate the opportunity. I quite like FocusMate but the emails drive me nuts.

When I'm logged in I can change email settings for Calendar Invites (I definitely want these) and Performance Reports (if I could track my own performance metrics I'd want these but for now they're really just a prompt to schedule mores sessions like every other FocusMate email). Opting out of Performance Reports apparently doesn't opt me out of "FocusMate Stats" emails even though they're basically the same.

Clicking "manage subscriptions" at the bottom of an email takes me to a _different_ page of email settings that's almost impossible to figure out - Engagement? Outreach? Important Messages? CEO? I have no idea what I'm opting into or out of.

Important messages sounds like something I want - I'm glad I got your emails about the new subscriptions, for example. (Was that an "important message" or "CEO"?) But important messages also seems to include not so important stuff - like the email of dubious veracity about the unemployed food truck guy who turned his life around in a week by scheduling a ton of FocusMate sessions. That was (yet another) email trying to get me to schedule more sessions.

I like FocusMate and I think it's is well worth $5/month but any email that ends with some version of "book more sessions" is an email that I don't want or need.

<comment><USER6> Great feedback, thank you.

We're still learning how to use our email tool optimally, and we have some fixes to implement, which will help reduce/elimiate the confusion you're talking about.

Over time we can also integrate more of those emails directly into the app, in your settings, alongside the Cal invites and Performance reports. (Doing that requires more engineering work, so is a bit slower.)

As far as the duplicate stats email: I just removed it. Our bad!

Thank you again so much for the feedback. Keep it coming!

Taylor

</comment></comment></comment></comment></comment><comment><USER19> I read comments here, I watched the video. I still have no idea what this is actually for.

There is chat app, maybe someone can see your screen. I don't know.

<comment><USER6> How it works: you and another user video-conference for 50-minutes to hold each other accountable and keep each other company. Focusmate makes it easy to find a partner 24/7/365.

</comment></comment><comment><USER20> TL/DR: Book appointments on your calendar to get work done and stick to them. Shut off notifications while you're in there.

I've been working from home for a decade now, and basically I think this is bonkers (no offense, I see the founder is here posting). With all the tools out there if you really want to do that pair up with a coworker and do it with an existing tool. I don't work in pajamas or do anything dumb but I have zero (0) interest in having someone I don't even work with having a video feed into my house. That's as a man, don't even get me started on how uncomfortable I'd be if I wasn't a cis / straight guy.

<comment> 5874-4b22-a4e0 Just get a offline video recording device, and record yourself on loop if you want to have the feeling of being watched. Then just repeat what you did before and after the session for accountability.

This concept is creepy af, and its hilarious to have to pay for it.

<comment><USER21> What's possibly hilarious is to have never tried it, and to suspect that its concept is creepy.

Sure, the webcam is on, but as long as the person at the other end seems to be reasonably busy with something, it should not be bothersome at all. And of course, you can always exit a session.

On having to pay for it - why not? Why not try paying for a service that asks for a reasonably designed monthly payment term instead of annual one time payments? Or the ones on which ads cover half the page?

Entrepreneurs need words of encouragement.

</comment></comment></comment><comment><USER22> What in the WE is Virtual Coworking ? Does it elevate my consciousness with Blockchain sped up by IOT devices powered by 5G which funnel data through Kafka to backend instances that have been clustered up the wazoo with Kubernetes !

</comment><comment><USER23> Could someone summarize what is a "virtual coworking" or "accountability partner"? I don't really understand the concept. Is it about having a video chat with a person who is watching you work?

<comment><USER24> I don't think a simple description will cut it; the idea is that with co- working, you meet up (physically) at some space, and all work on your projects. The simple fact of not being at your home and in the presence of other people with work to do helps a lot with productivity, even if you don't speak at all. This, I understand, is an attempt to virtualize this effect.

It may seem a bit silly but I honestly dig it, I have immense trouble getting myself to work at home, but co-working I can get into flow for hours at a time. I think that this sort of virtual co-workers might just work, because I think I'd feel really weird if I went all the trouble to set up a session, "meet" with someone and then just browse HN for 50 minutes. I'd be much more likely to feel "indebted" to the other guy's time, even though we have no professional relationship as such.

It's just a psychology hack, no more, no less.

</comment></comment><comment><USER25> Focusmate started as a productivity hack and became a community for me

</comment><comment><USER26> This is my nightmare, it's incredibly exhausting to be watched on video. I really enjoy dead silence when working. No music, convo, etc. Check ins a few times a week is perfect for me.

</comment><comment><USER27> The "How it Works" section should be at the very top of the page, because it's the part that tells you wtf this service does.

</comment><comment><USER28> I finally feel that I don't have to worry about my writing. It will happen because I have Focusmate! Amazing, thank you!</comment>


Is someone trying to build the real Genisys app from Terminator? - <AUTHOR> http://genisys.io

<comment><USER2> It is either a fan site or promotion for the Terminator series movies.

It seems to count down for some time in 2017. That is around the time Genisys actually launched in the movie and they release part two of the trilogy in real life.</comment>


Ask HN: How to self-host comments on your otherwise static blog? - <AUTHOR> I am using pelican to self host my blog/website. What is the best way to self-host comments?<p>What is the scope of GDPR compliance with storing these comments? <comment><USER2> There's an open source version of [https://commento.io/](https://commento.io/) for self-hosting a comment system. [https://news.ycombinator.com/item?id=19210697](https://news.ycombinator.com/item?id=19210697) lists several others like [https://github.com/posativ/isso](https://github.com/posativ/isso)

</comment><comment><USER3> I would instead of hosting comments on the site itself offload comments to Twitter/HN and link to it from the article like [https://overreacted.io](https://overreacted.io)

</comment><comment><USER4> I wrote a self-hosted "comment server" a few years back, but in the end found it was more annoying than useful.

In the end I just setup a simple CGI script which takes each submitted comment, writes it to /srv/comments/pending/ and then sends me an email.

When I rebuild the blog all the comments from /srv/comments/approved are automatically inserted at the foot of the appropriate post. I have a manual step where I move the comments into the right directory "/approved" vs "/spam".

It isn't ideal, but it is simple, reliable, and works well at the level of scale I deal with at [https://blog.steve.fi/](https://blog.steve.fi/)

<comment><USER5> Hmm, I actually got an idea from your comment and the other comment suggesting to off-load the comments to a social site such as HN or Twitter: maybe instead of hosting the comments yourself, you just have a script that automatically aggregates comments from multiple sites and displays them on your site. I am not sure this is allowed by the Twitter/HN terms of use though.

</comment></comment><comment><USER6> The best balance of usability, Freedom, and civility for me has been relying on people to email me, then sometimes—and with permission—edit their comment into my posts/pages.

<comment><USER7> That's what I do. Each of my pages has a comment link, it's just a mailto:. If I think the comment is useful, I'll append it to the comment section with my reply.

<comment> im3w1l-alt I bet it has a higher abandon rate than a webform. But that may be desirable I guess.

<comment><USER7> I'm sure it does, but, as you say, not a bad thing.

</comment></comment></comment></comment><comment><USER8> Another option is to host the comments in Github/Gitlab issues. There are several plugins that allow users to login using OAuth and post comments.

Gitalk is one of them: [https://github.com/gitalk/gitalk/](https://github.com/gitalk/gitalk/)

Vssue supports both GitHub and GitLab, and allows users to edit and delete their comments: [https://vssue.js.org/](https://vssue.js.org/)

And there is also Gitment: [https://github.com/imsun/gitment](https://github.com/imsun/gitment)

</comment><comment><USER9> I changed my blog to be static. I don't trust any of these embedded comment systems, and don't don't want to risk the legal burden of hosting comments myself. I killed off a small community this way, which felt not great :(

I guess it was assumed that a GDPR-compliant software infrastructure would be able to grow from the ashes, but I haven't been following, and don't know what the state of the art is. It seems people mostly offload to other platform (twitter/discord) rather than host themselves now?

I miss when websites were more participatory - I respect + envy people who still do blogs with lively comment threads.

</comment><comment><USER10> As someone who has been through this process, I strongly agree with the advice of Lammy and nikivi posted in this thread.

Unless you have a high-traffic blog with lots of user engagement, I think it's best to keep your blog clean and handle comments/feedback elsewhere.

</comment><comment> dane-pgp It would be nice if there were a service where people could write their comments and have them expire after, say 24 hours, but the blogger could run a script which downloads them before that happens. By having a local copy of the comments, the blogger could check them and include the approved ones into their static content.

Each comment would be associated with a salted hash based on either an IP address (for anonymous comments) or an account on a social login provider (like Google or Facebook). By default, a user could only post 1 comment every 24 hours, but the blogger could then publish a whitelist of people who are exempt from that restriction.

If this were an open standard, then the blogger could switch their comment provider at a moment's notice, without losing any data.

<comment><USER11> That open standard exists, it's called Webmention. You can use a free Webmention server like [https://webmention.io](https://webmention.io) and download comments with your API. Comments are just webpages where people respond to your blog.

Webmention works like this: Someone writes a reply on their blog and then sends you a Webmention. You can add it to your site or do whatever with it. It's decentralized and there's no vendor lock-in.

<comment><USER12> So it's just like _trackbacks_ we used to have in the late 2000s?

<comment><USER11> Webmention is the current standard for doing what trackbacks did, and simplified. Webmention doesn't require any sort of RDF or special code like trackbacks. Verifying a Webmention only involves looking in the HTML for any link to the page being mentioned.

</comment></comment></comment></comment><comment><USER13> [https://schnack.cool/](https://schnack.cool/)

</comment><comment><USER14> Easy: [https://github.com/glosa/glosa-server](https://github.com/glosa/glosa- server)

</comment><comment><USER11> Use Webmention W3C standard and the free service at [https://webmention.io/](https://webmention.io/)

Webmention works like this: Someone writes a reply on their blog and then sends you a Webmention. You can add it to your site or do whatever with it. It's decentralized and there's no vendor lock-in.

See it in action here: [https://aaronparecki.com/2020/05/04/10/](https://aaronparecki.com/2020/05/04/10/)

You can even use services like [https://brid.gy](https://brid.gy) to back feed Twitter comments into Webmentions.

<comment><USER15> I just finished setting up brid.gy for my blog a week ago. while I havent handle and display the comments or reactions to the posts, it is satisfying to see the response from my friends on twitter or mastodon about my contents.

reading this thread makes me want to finish the reaction displayer design & script :D

</comment></comment><comment><USER16> I haven't tried it yet, but I came across Staticman which seems really cool: [https://staticman.net/](https://staticman.net/)

Netlify also provides support for forms which could be used to accomplish this.

Can't speak to the GDPR aspect, but I don't imagine it would be much of an issue for just saving and displaying comments.

<comment><USER17> Watch out, it is no longer maintained.

I used Staticman for a couple of years and it worked fine. But GitHub changed their API policy which broke Staticman.

Also, spam is really hard to handle with this. I had to unplug Staticman from my site because of it.

<comment><USER18> > GitHub changed their API policy which broke Staticman.

Can you clarify this / have any links? Thanks

EDIT: Ah, just tried the demo (now broken). It looks like it was allowing internet random's to post to GitHub under a single account owned by the site or the project, and I totally get why GitHub is going to pull that ASAP.

</comment></comment></comment><comment><USER19> I switched from Isso to Commento, but the latter has had an open bug that prevents login for almost a year:

[https://gitlab.com/commento/commento/-/issues/174](https://gitlab.com/commento/commento/-/issues/174)

For my site, I think I might as well not add comments at all, as I haven't found them to be terribly useful. The most useful discussion happens on HN, Twitter/Mastodon and email.

</comment><comment><USER20> Plug for the platform that I work on, Coral[0]. We support newsrooms in many regions (including those that need to be GDPR compliant). You can self host the application on Heroku pretty easily with the button or run on a server if you like too.

[0]: [https://docs.coralproject.net/talk/](https://docs.coralproject.net/talk/)

</comment><comment><USER21> I had a blog with comments. But spam made it painful to administer. Almost nothing beats spam except for very sophisticated captchas but then normal people also have trouble writing comments. So I have no comments on my blog now. If you want to "comment" you'll have to email me directly.

</comment><comment><USER22> Well it's not self-hosted, but I made [1] YComments to allow _hacker news_ comments on a static website.

[1] [https://ycomments.benwinding.com/](https://ycomments.benwinding.com/)

<comment><USER23> Could have called it YCommentator :)

<comment><USER22> My god, that is brilliant!

</comment></comment></comment><comment><USER24> That's actually a good question. Yes hosting static htmls have been super easy for a decade. (Might have been getting harder recently actually lol) But managing comments always have been a headache.

</comment><comment><USER25> I would add utterances [0], even if its not self-hosted.

[0] [https://github.com/utterance/utterances](https://github.com/utterance/utterances)

<comment><USER17> Last time it was posted, it was noted that utterances breaks GitHub's ToS in pretty much every way, and they could pull the plug on this really fast.

<comment><USER18> Can you clarify this? When you said this I assumed it was allowing internet random's to post to GitHub under a single account owned by the site or the project, and I totally get why GitHub is going to pull that ASAP (have seen that and got in rows over that before). But I just checked and it looks like you have to authorise the app and hence Utterances is posting under your GitHub account?

</comment></comment></comment><comment><USER26> Come on people, the OP asked for a _self-hosted comments_ solution. The number of OT replies is excessive, particularly when the same OT reply is repeated by several people.

</comment><comment><USER27> I have built it myself using websockets. Wasn't that that hard or bad. [https://worktheme.com](https://worktheme.com)

Happy to answer questions.

</comment><comment><USER28> Anything for inline comments / annotations?

<comment><USER29> Take a look at [https://hypothes.is/](https://hypothes.is/)

</comment></comment><comment><USER30> I'd be far more worried about spam and malicious content than GDPR. Always assume someone will be trying to cram ads, pornography, and viruses into anything you create that allows user content.

</comment><comment><USER31> My blog is decently high-traffic and has been static/Pelican for several years.

After using Disqus for a while I decided to drop comments entirely because they're more trouble than they're worth. A quick write up about it -- [https://eli.thegreenplace.net/2018/turning-off-blog- comments...](https://eli.thegreenplace.net/2018/turning-off-blog-comments/)

TL;DR: don't.

<comment><USER32> Most of your issues seem to have been with Disqus and not with comments on your page in general, though I agree it's probably not worth attempting these days. Blog posts can be linked on FB, Twitter, Reddit and other places and those pages can deal with spam and their monetization better on their own premises, while you are not confined to one particular flavour of filtering/censorship for user comments (as with one service like Disqus). OTOH I don't particularly like the idea of actually interacting with Twitter/FB users as a blogger.

</comment></comment><comment><USER33> I thought once of using NNTP for comments (the blog messages themself can also be readable with NNTP). You can have a link from a static web page to separate page that displays read-only comments, and has instructions to post (you could also use iframe, although I do not recommend that; a normal link would do better, I think). That is what I wanted to do, at least.

(I don't know about GDPR, though, sorry)

</comment><comment><USER34> How about telling your users to post on github/gitlab issues if they have something valid to add?

</comment><comment><USER35> There's also Talkyard Blog Comments: [https://www.talkyard.io/blog- comments](https://www.talkyard.io/blog-comments)

GDPR: People can download their personal data, and delete their own accounts, via their user profile pages.

No ads, no tracking. Open source. (I develop Talkyard.)

</comment><comment><USER36> AFAIK, GDPR only _really_ becomes an issue for you, if your blog crosses a certain threshhold of views/comments.

Not sure where I read it, but it was in the range of something around 10,000 per day/week/month.

Definitely not something to crack your head over, if you just want to host a personal blog (unless you're a celebrity?).

SOURCE: I self-host a personal blog in Germany, and had read up on it a year or two ago.

<comment><USER37> Datensparsamkeit! There are more reasons to wanna to be in control of the data if your users instead of selling it off easily (e.g. the trust of your users). Additionally it can feel good to just _know_ what happens instead of telling yourself: "I use google analytics like everybody else — that _must_ be okay"

<comment><USER36> I actually develop my own solutions, there is no third-party analytics involved in my blog, the only "analytics" I do, is to keep track of which IP visits what resource, the only cookies that are set on my blog are session and chain IDs.

If you have the information available, on what the mentioned threshold is, please do share.

For the less than 10 visits a day my blog receives, of which 98% are bots, I'm not going to do a deep dive into GDPR policies.

In Europe, law doesn't work like in the US in the way that it's to be taken literally, but in the way that the law was intended - which is not to discriminate amateur blogs, but to enforce data protection amongst the big players, i.e. Facebook, YouTube, etc...

Therefore, I still stand by my original claim: For an amateur blog, don't crack your head over GDPR.

EDIT: Provided, of course, you don't use the tools of the big players, e.g. Google Analytics.

</comment></comment></comment><comment><USER38> There is another tool call disqus. It's free and is really easy to integrate into your own page. You can check that out on my blog page.

[https://blog.phuaxueyong.com/post/2020-05-03-3-more-cloud- de...](https://blog.phuaxueyong.com/post/2020-05-03-3-more-cloud-design- pattern)

</comment><comment><USER39> Disqus was baked into the template I used for my blog so I kept it: [https://thoughts.willcipriano.com/weird-python- tricks/](https://thoughts.willcipriano.com/weird-python-tricks/)

It works well and is simple to implement.</comment>


Ask YC: What is an appropriate valuation for a startup that is brand new? - <AUTHOR>

If there is just an idea and a bit of research, what is a fair valuation for an angel investor to invest in a startup at? <comment><USER2> That's an unanswerable question the way you put it.

There is absolutely no information even about size of the potential market, business model, competitive arena, price points, required capital investment and so on.

You will have to do a bunch of homework (such as a minimalist business plan) to give you an idea of what you expect to do with your business, then you can go and put a value on it.

Garbage in -> garbage out.

YC has turned the angel investor game in to a horse race, they bet on the teams, to a much lesser extent on the ideas.

'conventional' angel investors will likely not be able to evaluate you (and possible co-founders) as a team, but they may be able to understand the business proposition behind your idea once you can explain it to them.

That will be central to the valuation, as well as your expertise and skill relative to what is needed to develop it and take it to market.

A couple of weeks of hard work should get you to the point where you will be able to answer your own question, after all, you're the one that's being diluted so you should know the value of what you have better than anybody.

</comment><comment><USER3> Somewhere between $0 and $20,000, probably much closer to $0; depends on your credentials, the intuitive strength of your idea, and how hard it is to build.

You're asking the wrong question, though. Regardless of whether you can get an investment (and sure, you can always scrounge up $2000 from somewhere), _this is the worst conceivable time for you to try to take an investment_. You are optimizing for terms will ultimately cripple your business.

Build something first.

<comment><USER2> Don't rule out the possibility that it is a bad idea that looks good (value < $0, you will lose whatever money you throw at it).

Or an absolutely fantastic one (probably still < $20,000).

</comment></comment><comment><USER4> Question: Are you looking for an angel investor, or has one approached you?

If you are looking for one and have no contacts then I don't think there is really an answer to your question, but somewhere close to zero.

However if someone has approached you then that is a different question. I've talked about ideas in the past and had people ask me about investment. The way I value that is if I am going to work the next five years at startup levels of stress and hours I value my income at US$200,000 a year. So five years (commitment I would assess putting into it) x 200K is $1,000,000. Then it is up the investor as to what percentage they are after. So 10% means I would want them to invest around $100K.

That all needs to be balanced by your level of experience, financial expectations, how much you need the money - and how likely you perceive the potential to accept the concept.

</comment><comment><USER5> It depends primarily on the track record of the founding team. If the team has a history of being able to execute and the idea is promising, I'd say you can raise money on valuations between $1-3 million pre with just a powerpoint and some background research.

If the team has no track record, it will be much, much harder.

</comment><comment><USER6> Others are saying you can't place a value. I don't buy that at all. People do it every day. The people that are _truly_ capable of building a successful business are few and far between. An investor is lucky to find someone worth betting on.

From your perspective taking investment is a serious commitment. You're promising to to spend the next N years dedicating yourself to making the company successful. That's worth quite a bit if you're at all likely to succeed.

Just ask yourself how much equity would you sell and for what price?

I think a sane ballpark is something like 10-15% for $100-200k, 20-25% for $500k, or 30-35% for $1M. But again, that's just a ballpark.

<comment><USER7> "People" aren't saying you can't place a value on it. "People" are saying you can't place a value on it based on 121 characters of text, less than half of which even describes the startup in question. If you rephrase the question as "What is this thing in my hand worth?" you haven't changed _all_ that much....

<comment><USER6> You can make some common assumptions:

1) There are (or will be) 2 founders that are prepared to dedicate years to the venture

2) They're able to convince an investor to put money in (otherwise valuation won't matter).

To me that's enough to justify the ballpark valuations I gave. You don't need to know their specific market, product, or anything else.

<comment><USER2> You can't put a value on a company that is based on an unknown idea with research by an unknown individual with unknown skills.

Sorry but no. I don't care if the founders are prepared to dedicate the rest of their lives to it (assuming it is founders and not founder), after all you could dedicate your life to making a better mousetrap but for me that would be worth $0.

The guy is basically asking how much his time is worth without giving his qualifications for all you know he's flipping burgers at McD's.

My brother in law came up with an idea for a better garbage can, not immediately obvious and not in production anywhere, after some 'research'.

What is it worth?

For me it's worth $0. He has no background in manufacturing, sales, marketing or design, he does not have anybody that would dedicate his life to it, and he's not prepared to mortgage his house and let go of his day-job to pursue it. So it won't be going anywhere.

I don't see this guy making any statements about what he will bring to the table either other than the idea, not even implicit ones, no statements about commitment or anything.

So, more info is needed. Both about the idea and the OP (track record would help but likely none or he wouldn't be asking the question).

No realistic valuation ever rested on this little info.

Sure 'angel' investments fall in to a certain range, say 0 to 10% of the stock for 0 to $1M. But that's like saying the sun will be shining tomorrow, that's not an answer to the question.

<comment><USER6> It seems like you're being intentionally obtuse. He asked a general question about startup valuations. A general answer is perfectly possible. Whatever...

</comment></comment></comment></comment></comment><comment><USER8> "Fair"? There's nothing fair about valuing a company at millions of dollars when it's just a few guys and an idea. It's about getting the right amount of investment while not selling too much of the company (but selling enough to make it with the investors time).

Check: [http://www.avc.com/a_vc/2010/10/employee-equity- dilution.htm...](http://www.avc.com/a_vc/2010/10/employee-equity- dilution.html)

Because you've offered zero information to dial it in, $500k to $4m post-money as a wag. Depends on team, if you're in the valley, and your ability to create a market for your stock.

<comment><USER3> You're scaling this to typical SF angel investment sizes, right? I got the impression that this was, like, one guy.

</comment></comment><comment><USER9> $0.

</comment><comment><USER10> # of programmers * months to MVP * credibility * $10k.

Even a mockup is better than nothing, but you'd do well to find your own tech partner.

<comment><USER11> So if it takes a large number of programmers a very long time to produce a product, the valuation is higher than a small amount of programmers creating a viable product quickly?

<comment><USER10> It would need to be :-)

What I'm driving at is that some ideas you can do a minimum viable product very quickly, other more ambitious ones might need months of work - I was trying to avoid making assumptions about what this unknown idea might be, and throw the focus on potential cost to launch. The question is so open-ended that it _sounds_ like an interesting idea without any financials yet; so I'm trying to estimate the cost of satisfying my curiosity about whether or not a market exists for whatever-it-is.

A webapp that solves a particular problem by matching buyers and sellers might need only a week of work to begin being useful. But not all ideas are so straightforward - for all I know s/he might be imagining the next evolution of the spreadsheet.</comment></comment></comment>


Ethnic cleansing makes a comeback – in China - <AUTHOR> https://www.washingtonpost.com/opinions/global-opinions/ethnic-cleansing-makes-a-comeback--in-china/2018/08/02/55f73fa2-9691-11e8-810c-5fa705927d54_story.html <comment><USER2> I was under the impression that this is far from a new development in China? More broadly as we've seen in Myanmar and elsewhere, this is no comeback, it's just... how people treat each other when they can get away with it.

</comment><comment><USER3> This article is blocked by a paywall disguised by a "free" option that coerces you into giving up your rights.

<comment><USER4> On the Washington Post? No way!</comment></comment>


Identification of Pre-Existing Adaptive Immunity to Cas9 Proteins in Humans - <AUTHOR> https://www.biorxiv.org/content/early/2018/01/05/243345 <comment><USER2> About two thirds of humans have antibodies against the protein.</comment>


Whiteboard Interview Advice I Ever Received - <AUTHOR> https://hackernoon.com/the-best-whiteboard-interview-advice-i-ever-received-3ebbfa72e4a <comment><USER2> The actual title is "The Best Whiteboard Interview Advice I Ever Received".</comment>


Supercharged Tuberculosis, Made in India - <AUTHOR> http://www.scientificamerican.com/article/supercharged-tuberculosis-made-in-india1/

<comment><USER2> While it looks grim, I think wheels are in motion. This article by World Bank - [http://www.worldbank.org/en/news/feature/2013/05/09/india- ba...](http://www.worldbank.org/en/news/feature/2013/05/09/india-battling-tb- in-indias-slums) puts things more in perspective.

Bottom line:

1\. Government has increased spending on Tuberculosis diagnosis and treatment.

2\. Organizations like Gates foundation ([http://www.gatesfoundation.org/What- We-Do/Global-Health/Tube...](http://www.gatesfoundation.org/What-We-Do/Global- Health/Tuberculosis)) are doing good job in getting things in motion.

3\. NGO's like Operation Asha([http://www.opasha.org/](http://www.opasha.org/)) are doing tremendous job ensuring patients take their medication properly.

A big part of the problem seems to be diagnosis and proper treatment before the disease becomes drug resistant. This quote from linked article:

>All too often, patients are misdiagnosed and wrongly treated by private providers who then dump them, broke and drug-resistant, onto the public health system.

</comment><comment><USER3> Really puts the singularity hype into perspective. For years I've been hearing from them about radical medical advances just around the corner, and here we see that on this front, rather than making exponential progress, or even just progress period, medical "science" is actually losing rather than gaining ground.

<comment><USER4> I don't think your view quite reflects reality.

\- We have made and will continue to make massive medical advances. Look at things like cancer survival rates, for example. \- Drug-resistant TB is actually treatable, and the reason for its existence in the first place is poor treatment practices that encourage the development of resistance. If this is a failure of anything, it's healthcare protocol rather than science.

<comment><USER5> I looked at the cancer survival rates. Over 30 years this looks like slow progress to me:

[http://healthhubs.net/images/cancer-survival- trends.gif](http://healthhubs.net/images/cancer-survival-trends.gif)

</comment></comment></comment><comment><USER6> What i never actually got- why do we have to wait for this to happen in the wild ? What prevents us from cultivating connected tissuesamples, and breed the superbugs of the next generation in the lab, so that countermeasures are available when it happens?

I know that mutations (virus) and recombinations (exchange of dna between bacteria) are unpreditable - but most of them would remain local - only those infectious enough to be transfered are of interest, in the wild as in the lab.

<comment><USER7> Random mutations that give resistance may evolve differently even under the same evolutionary pressure.

You'd effectively get two independent strains which might or might not be sensible to the se drugs

</comment></comment><comment><USER8> Part of the problem is how easily antibiotics are available over the counter in India. No prescription required.

A large number of people self-prescribe or take the advice of non-medical people when looking for a cure.

I've seen folk take some pretty serious stuff (Tetracycline, Streptomycin etc.) on advice from the sales-staff at their local pharmacy.

The government has done little or nothing to stop this behaviour.</comment>


I'm dreaming of a… statistically modelled White Christmas - <AUTHOR> http://www.guardian.co.uk/lifeandstyle/us-news-blog/2012/dec/23/dreaming-of-a-white-christmas <comment><USER2> We're all out of news today in the UK so let's talk about the weather... in America.</comment>


Ask HN: How do you track hours for a project?  - <AUTHOR>

I've recently started doing some freelance work that is billed by the hour and I feel like I spend too much time on figuring out how many hours I've worked.
I have searched for a solution and have found a few that might fit the bill, but wanted to ask the HN community what solutions work best for you.  My short wishlist is:
Easy to start/stop timers Easy to edit times (I occasionally forget to stop a timer and need to subtract some time)
Print out a report of hours for a given period of time Mobile device support <comment><USER2> I use Toggl.com. They have a desktop app and an Android app.

</comment><comment><USER3> I've tried a lot. My top three favorites are:

      * freshbooks
      * letsfreckle.com
      * emacs org-mode or planner-mode

</comment><comment><USER4> As a web developer, I used the [Project Fork Plugin] for the Joomla CMS. You can even get mobile phone friendly templates for access when out of the office. Works great if you have your own server space and a sub domain.

Looking for a local solution? There's a well built Linux panel addition under [Project Hamster]. Its Slick, Fast & Simple with reports.

</comment><comment><USER5> Harvest (getharvest.com I think) is pretty nice. I used the free plan for about 6 months til I outgrew it and the paid plan was $12/month. Really great time-entry system.

<comment><USER6> Agree Harvest is great and offers a built in invoicing system with reporting, plus it's cheap.

</comment></comment><comment><USER7> I just use Billings for OSX—simple timer in the menubar but it takes a few more steps to modify/delete timeslips compared to adding one.</comment>