user17758: The tag animation-mistakes exists, with 5 questions tagged. However, it doesn't really seem like it belongs here. 
A tag is something set by the question asker: How can you know if something is an animation mistake before you have the answer? In comparison, it would be like if we had a tag named plot-hole. The fact that the problem is being caused by an animation mistake or a plot-hole isn't likely to be known by the asker, only by the answerer; so, it seems silly to have a tag like this. 
Two of the 5 questions tagged (this and this) are actually asking if it is an animation mistake, but these questions could have just as easily asked, "Why is ___ this way? This seems weird because ____". 
I'd like to remove this tag from our site. 
Note that by removing this tag  I'm not moving to have these questions implicitly disallowed from the site. Instead, I assert that a series tag alone works well for any kind of question that would result in the answer involving an animation mistake. 

user7579: I mostly agree with Michael's points about this tag, and in particular I think his comparison to a plot-hole tag is apt, because all those animation-mistakes questions he links are pretty much asking about plot holes, incredibly minor ones introduced by mistakes during the animation process.
Let's run down some of the criteria that other SE sites use to decide whether to keep a tag.
The Stack Exchange Meta guide for when to burninate a tag suggests asking yourself the following questions when deciding whether to do away with a tag:

Does it describe the contents of the questions to which it is applied? and is it unambiguous?

It kind of describes the contents of the question, but it can never fully describe them. I wouldn't say it's unambiguous. "Animation mistake" is not terribly precise. Is it a mistake if the animators drew something off-model? Is it a mistake if they didn't do it on purpose, but not a mistake if it was intentional? Is it a mistake if a character's hair is a little less floofy in one scene? Is it a mistake that they ever animated El Cazador de la Bruja? (It was definitely a mistake that I sat through that entire miserable sod of a series.) The question Why is Dragon Ball Super's animation quality so terrible? uses the tag in a completely different way than the other questions, but I can't say that either way is wrong based on the tag's name. The tag wiki unhelpfully tells us that the tag is "For questions related to mistakes in anime-series." If we do decide to keep it, we definitely should clarify what kind of questions it goes on.

Is the concept described even on-topic for the site?

Yes. Moving along.

Does the tag add any meaningful information to the post?

Kind of. Not really. The questions Michael links are all basically about plot holes, so the most important thing is knowledge of the series, not knowledge about animation. If we used this tag only for questions that required technical knowledge about the animation process, it would add information, just as tagging a question with both a series tag and japanese-language adds information. (The Dragon Ball Super question actually does use the tag this way.)

Does it mean the same thing in all common contexts?

Pretty much. Animation mistakes are mistakes in animation. The term is ambiguous (what constitutes a mistake?), but that's a definitional problem, not a contextual problem.
According to these criteria, this is not a great tag, but it's not world-endingly awful. It's mostly harmless and can safely be ignored if we choose.

Science Fiction and Fantasy has used a rather strict nine-part test to decide whether a tag is allowed to exist. Recently there's been some controversy over it, but let's give it a try, as long as we don't take the results too seriously. A tag gets +2 points for each "Yes", +1 for a "Sometimes", and -1 for a "No".


Does it make sense to be an "expert" in proposed?


SF&F defines "expert" for their purposes like this:

For our purposes, being an "expert" in a tag means: 1) if the only thing someone knew about a question was that it was tagged proposed, that would be enough information for them to feel confident about trying to answer it, and 2) it's reasonable for someone to have a lot of knowledge about proposed as a separate subject, and not only because it's a subset of a larger topic (e.g. would someone know a lot about light-sabers on their own, [or] only because they're an expert on everything about star-wars)

It does not really make sense to be an expert in animation-mistakes. To know the answer to any of these animation-mistakes questions, you do have to be an expert in the series (other than the Dragon Ball Super one, which represents a whole different problem with this tag). -1.

Does it make sense for a question to be tagged only with proposed?

Not really. If any of those linked questions hadn't been tagged with the series and had only been tagged animation-mistakes, they would be missing vital information. -1.

Does proposed have a single, universally-unambiguous meaning?

As I argued above, the meaning of "animation mistake" is ambiguous. It made sense as a tag for the One Piece questions about arms that should have be bitten off and gloves that may not be on the correct hand, but it also makes sense for Why is Dragon Ball Super's animation quality so terrible?, which is not the same kind of mistake at all. -1.

Is proposed likely to be used correctly just based on it's name?

I'm not even sure what the correct usage is, so I'm gonna have to say "Sometimes". +1. 

Are there "enough" (> 15) but not "too many" (> 10% site-wide) questions that qualify for proposed?

We could probably dig up a couple more that could have used this tag, but I'm not sure about 10 more. -1.

Are people like to use proposed to find questions to answer?

I doubt it. I have my favorite shows. I like answering questions about my favorite shows. Some of those questions might come up from an animation mistake. But I can't imagine myself ever just wanting to answer a bunch of questions that come up from animation mistakes. -1.

Are there likely some users (be objective!) who will favorite or ignore proposed?

Apparently this tag has three followers. So I guess this is a +2.

Could proposed be reasonably used to feed questions to a specialized chat room?

Maybe. Gonna say +1.

Can proposed be used to search for questions (for any reason) in a way that keyword searching cannot accomplish?

Yes. There's no obvious combination of keywords that would bring up all five animation-mistakes questions, so +2.

Very roughly speaking, tags that score > 12 are "good" tags, tags that score < 8 are "terrible" tags, others are likely good but may need some clarification/renaming/etc.

By my count, this tag scores +1, so it's pretty terrible.

Based on these criteria, I agree with getting rid of this tag. Because it's on so few questions, this won't be a lot of work, and I really don't think the tag adds much.
The Dragon Ball Super question is the only one where I think the tag adds necessary information. However, it was closed as a duplicate of Is intentionally producing a lower quality TV release unique to anime?, and that question is tagged anime-production, which describes its content even better than animation-mistakes. So I think we should get rid of animation-mistakes, tag the Dragon Ball Super question with anime-production instead, and reduce to other four questions to just the series tag.

user17758: The idea behind a tag is to have a way to tag a question for people with knowledge about a subject to find questions that are within their scope of expertise. Our Help Center defines it as:

A tag is a word or phrase that describes the topic of the question. Tags are a means of connecting experts with questions they will be able to answer by sorting questions into specific, well-defined categories.

Animation mistakes are not the topic of a question, but rather the conclusion and result to research or answer to a question. Ryan's suggestion of retagging questions to animation-mistakes after an answer deems it to be an animation mistake is not the way tags are meant to work. This line of thinking isn't in line with the way other tags are handled either; since we don't retag questions to meet the criteria of an answer in any other cases. 
Also, in such a scenario, who is really the judge of when to retag? While we do have community accepted answers indicated by upvotes on questions, it's rare that a question like this will have an official answer that would guarantee that it was a mistake: instead, answers to these types of questions rely on inference and references to source material.
Tags represent subjects that a group of people could have expert knowledge about. It seems unlikely that anyone could have expert level knowledge over the topic of animation mistakes. Instead, someone could have expert knowledge over an anime, including the mistakes that were made when adapting it to anime. The tag for the anime in question is sufficient in this case to find the correct person to answer the question. 

17758: <p>The tag <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a> exists, with 5 questions tagged. However, it doesn't really seem like it belongs here. </p>

<p>A tag is something set by the question asker: How can you know if something is an animation mistake before you have the answer? In comparison, it would be like if we had a tag named plot-hole. The fact that the problem is being caused by an animation mistake or a plot-hole isn't likely to be known by the asker, only by the answerer; so, it seems silly to have a tag like this. </p>

<p>Two of the 5 questions tagged (<a href="https://anime.stackexchange.com/q/25753/17758">this</a> and <a href="https://anime.stackexchange.com/q/21400/17758">this</a>) are actually asking if it is an animation mistake, but these questions could have just as easily asked, "Why is ___ this way? This seems weird because ____". </p>

<p>I'd like to remove this tag from our site. </p>

<p>Note that by removing this tag  I'm not moving to have these questions implicitly disallowed from the site. Instead, I assert that a series tag alone works well for any kind of question that would result in the answer involving an animation mistake. </p>
 7579: <p>I mostly agree with Michael's points about this tag, and in particular I think his comparison to a <a href="https://anime.stackexchange.com/questions/tagged/plot-hole" class="post-tag" title="show questions tagged &#39;plot-hole&#39;" rel="tag">plot-hole</a> tag is apt, because all those <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a> questions he links are pretty much asking about plot holes, incredibly minor ones introduced by mistakes during the animation process.</p>

<p>Let's run down some of the criteria that other SE sites use to decide whether to keep a tag.</p>

<p><a href="https://meta.stackexchange.com/q/239190">The Stack Exchange Meta guide for when to burninate a tag</a> suggests asking yourself the following questions when deciding whether to do away with a tag:</p>

<blockquote>
  <p>Does it describe the contents of the questions to which it is applied? and is it unambiguous?</p>
</blockquote>

<p>It kind of describes the contents of the question, but it can never <em>fully</em> describe them. I wouldn't say it's unambiguous. "Animation mistake" is not terribly precise. Is it a mistake if the animators drew something off-model? Is it a mistake if they didn't do it on purpose, but not a mistake if it was intentional? Is it a mistake if a character's hair is a little less floofy in one scene? Is it a mistake that they ever animated <em>El Cazador de la Bruja</em>? (It was definitely a mistake that I sat through that entire miserable sod of a series.) The question <a href="https://anime.stackexchange.com/questions/24570/why-is-dragon-ball-supers-animation-quality-so-terrible">Why is Dragon Ball Super&#39;s animation quality so terrible?</a> uses the tag in a completely different way than the other questions, but I can't say that either way is wrong based on the tag's name. The tag wiki unhelpfully tells us that the tag is "For questions related to mistakes in anime-series." If we do decide to keep it, we definitely should clarify what kind of questions it goes on.</p>

<blockquote>
  <p>Is the concept described even on-topic for the site?</p>
</blockquote>

<p>Yes. Moving along.</p>

<blockquote>
  <p>Does the tag add any meaningful information to the post?</p>
</blockquote>

<p>Kind of. Not really. The questions Michael links are all basically about plot holes, so the most important thing is knowledge of the series, not knowledge about animation. If we used this tag only for questions that required technical knowledge about the animation process, it would add information, just as tagging a question with both a series tag and <a href="https://anime.stackexchange.com/questions/tagged/japanese-language" class="post-tag" title="show questions tagged &#39;japanese-language&#39;" rel="tag">japanese-language</a> adds information. (The Dragon Ball Super question actually does use the tag this way.)</p>

<blockquote>
  <p>Does it mean the same thing in all common contexts?</p>
</blockquote>

<p>Pretty much. Animation mistakes are mistakes in animation. The term is ambiguous (what constitutes a mistake?), but that's a definitional problem, not a contextual problem.</p>

<p>According to these criteria, this is not a great tag, but it's not world-endingly awful. It's mostly harmless and can safely be ignored if we choose.</p>

<hr>

<p>Science Fiction and Fantasy has used <a href="https://scifi.meta.stackexchange.com/q/7871/28578">a rather strict nine-part test</a> to decide whether a tag is allowed to exist. Recently there's been <a href="https://scifi.meta.stackexchange.com/q/9215/28578">some controversy</a> over it, but let's give it a try, as long as we don't take the results too seriously. A tag gets +2 points for each "Yes", +1 for a "Sometimes", and -1 for a "No".</p>

<blockquote>
  <ol>
  <li>Does it make sense to be an "expert" in <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a>?</li>
  </ol>
</blockquote>

<p>SF&amp;F defines "expert" for their purposes like this:</p>

<blockquote>
  <p>For our purposes, being an "expert" in a tag means: 1) if the only thing someone knew about a question was that it was tagged <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a>, that would be enough information for them to feel confident about trying to answer it, and 2) it's reasonable for someone to have a lot of knowledge about <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a> as a separate subject, and not only because it's a subset of a larger topic (e.g. would someone know a lot about light-sabers on their own, [or] only because they're an expert on everything about star-wars)</p>
</blockquote>

<p>It does not really make sense to be an expert in <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a>. To know the answer to any of these <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a> questions, you do have to be an expert in the series (other than the Dragon Ball Super one, which represents a whole different problem with this tag). -1.</p>

<blockquote>
  <p>Does it make sense for a question to be tagged only with <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a>?</p>
</blockquote>

<p>Not really. If any of those linked questions hadn't been tagged with the series and had only been tagged <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a>, they would be missing vital information. -1.</p>

<blockquote>
  <p>Does <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a> have a single, universally-unambiguous meaning?</p>
</blockquote>

<p>As I argued above, the meaning of "animation mistake" is ambiguous. It made sense as a tag for the One Piece questions about arms that should have be bitten off and gloves that may not be on the correct hand, but it also makes sense for <a href="https://anime.stackexchange.com/questions/24570/why-is-dragon-ball-supers-animation-quality-so-terrible">Why is Dragon Ball Super&#39;s animation quality so terrible?</a>, which is not the same kind of mistake at all. -1.</p>

<blockquote>
  <p>Is <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a> likely to be used correctly just based on it's name?</p>
</blockquote>

<p>I'm not even sure what the correct usage is, so I'm gonna have to say "Sometimes". +1. </p>

<blockquote>
  <p>Are there "enough" (> 15) but not "too many" (> 10% site-wide) questions that qualify for <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a>?</p>
</blockquote>

<p>We could probably dig up a couple more that could have used this tag, but I'm not sure about 10 more. -1.</p>

<blockquote>
  <p>Are people like to use <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a> to find questions to answer?</p>
</blockquote>

<p>I doubt it. I have my favorite shows. I like answering questions about my favorite shows. Some of those questions might come up from an animation mistake. But I can't imagine myself ever just wanting to answer a bunch of questions that come up from animation mistakes. -1.</p>

<blockquote>
  <p>Are there likely some users (be objective!) who will favorite or ignore <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a>?</p>
</blockquote>

<p>Apparently this tag has three followers. So I guess this is a +2.</p>

<blockquote>
  <p>Could <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a> be reasonably used to feed questions to a specialized chat room?</p>
</blockquote>

<p>Maybe. Gonna say +1.</p>

<blockquote>
  <p>Can <a href="https://anime.stackexchange.com/questions/tagged/proposed" class="post-tag" title="show questions tagged &#39;proposed&#39;" rel="tag">proposed</a> be used to search for questions (for any reason) in a way that keyword searching cannot accomplish?</p>
</blockquote>

<p>Yes. There's no obvious combination of keywords that would bring up all five <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a> questions, so +2.</p>

<blockquote>
  <p>Very roughly speaking, tags that score > 12 are "good" tags, tags that score &lt; 8 are "terrible" tags, others are likely good but may need some clarification/renaming/etc.</p>
</blockquote>

<p>By my count, this tag scores +1, so it's pretty terrible.</p>

<hr>

<p>Based on these criteria, I agree with getting rid of this tag. Because it's on so few questions, this won't be a lot of work, and I really don't think the tag adds much.</p>

<p>The Dragon Ball Super question is the only one where I think the tag adds necessary information. However, it was closed as a duplicate of <a href="https://anime.stackexchange.com/questions/16668/is-intentionally-producing-a-lower-quality-tv-release-unique-to-anime">Is intentionally producing a lower quality TV release unique to anime?</a>, and that question is tagged <a href="https://anime.stackexchange.com/questions/tagged/anime-production" class="post-tag" title="show questions tagged &#39;anime-production&#39;" rel="tag">anime-production</a>, which describes its content even better than <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a>. So I think we should get rid of <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a>, tag the Dragon Ball Super question with <a href="https://anime.stackexchange.com/questions/tagged/anime-production" class="post-tag" title="show questions tagged &#39;anime-production&#39;" rel="tag">anime-production</a> instead, and reduce to other four questions to just the series tag.</p>
 17758: <p>The idea behind a tag is to have a way to tag a question for people with knowledge about a subject to find questions that are within their scope of expertise. Our <a href="https://anime.stackexchange.com/help/tagging">Help Center</a> defines it as:</p>

<blockquote>
  <p>A tag is a word or phrase that describes the topic of the question. Tags are a means of connecting experts with questions they will be able to answer by sorting questions into specific, well-defined categories.</p>
</blockquote>

<p>Animation mistakes are not the topic of a question, but rather the conclusion and result to research or answer to a question. Ryan's suggestion of retagging questions to <a href="https://anime.stackexchange.com/questions/tagged/animation-mistakes" class="post-tag" title="show questions tagged &#39;animation-mistakes&#39;" rel="tag">animation-mistakes</a> after an answer deems it to be an animation mistake is not the way tags are meant to work. This line of thinking isn't in line with the way other tags are handled either; since we don't retag questions to meet the criteria of an answer in any other cases. </p>

<p>Also, in such a scenario, who is really the judge of when to retag? While we do have community accepted answers indicated by upvotes on questions, it's rare that a question like this will have an official answer that would guarantee that it was a mistake: instead, answers to these types of questions rely on inference and references to source material.</p>

<p>Tags represent subjects that a group of people could have expert knowledge about. It seems unlikely that anyone could have expert level knowledge over the topic of animation mistakes. Instead, someone could have expert knowledge over an anime, including the mistakes that were made when adapting it to anime. The tag for the anime in question is sufficient in this case to find the correct person to answer the question. </p>
