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A user answered a question, gave the formula to the poster, and left it to the poster to calculate the numerical answer. Moderator andselisk then cited the meta-post Hint answers revisited and indicated that the answer wasn't good enough. I don't remember that discussion, nor ever having seen any meta-post that defines what a "good answer" is.

So -- What is a "good answer"?

From my perspective if the answer explains the principles needed to solve the problem, and derives a formula that is "good enough." Isn't plugging in the numbers and calculating a numerical result just mathematics?

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  • $\begingroup$ I don't have time for a full answer right now, but I think deriving the formula is 99% of the work already. However, I would also greatly appreciate giving a final numerical answer which brings it to 100%. After all, the Q is "how much Xe..." the Q isn't "what is the formula that tells me how much Xe..." The hint answer thing is relevant, but perhaps is being stretched a bit here: it was meant to get rid of completely useless answers, the sort of thing that you might nowadays see in the comment section, e.g. one-liner answers like "HINT: What orbital is the outermost electron in Na in?" $\endgroup$
    – orthocresol Mod
    Feb 1 at 11:20
  • $\begingroup$ @orthocresol - Your point about a "simple hint" being given as an answer is more or less what I had thought. As I stated in another comment on this webpage I have used the answer field to give a detailed comment when the comment space or formatting was inadequate. // The other thing that just occurred to me reading your comment is the answer supposed to answer the problem or the user's question? In this particular case the user's question was actually "Is my calculation wrong?" $\endgroup$
    – MaxW
    Feb 1 at 11:36
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    $\begingroup$ "is the answer supposed to answer the problem or the user's question?" I'm inclined to suggest that the answer should be as complete as possible, which means addressing as many points as possible (or as desired, because sometimes it's just too much to address everything). We could discuss this further; however, I wouldn't really want to find an overly prescriptive answer on this, because I'm not sure if there is really a right or wrong answer to your question. $\endgroup$
    – orthocresol Mod
    Feb 1 at 11:56
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    $\begingroup$ IMHO, the complete answers policy, including trivialities like plug in numbers ( good we need not to show how to calculate it ) means less answers the responders are willing to write, instead of targetting their resources to essential parts of more questions. Calculating the result, I feel like a lowly servant of the OP. It should be more like a partnership. $\endgroup$
    – Poutnik
    Feb 2 at 7:21
  • $\begingroup$ In many cases, numerical evaluation with all the MJ formatting for complex formulas is significant part of needed effort. Considering it takes for the OP much less time to type numbers on a calculator than for me to write it in MathJax, it is wasting of resources. It can be a tipping point for me to decide, if I would write an answer for a familiar topic. $\endgroup$
    – Poutnik
    Feb 2 at 11:45
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    $\begingroup$ @Poutnik I have a lowly electronic servant to calculate and format, see this link. You get the answer, and if you press export after that, you get a MathJax/Latex code near the bottom of the page. The calculation is from the two container problem. The calculator is written up in JChemEd and Chemistry Teacher International. $\endgroup$ Feb 2 at 18:03
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    $\begingroup$ @karstentheis Thanks for the interesting tip. $\endgroup$
    – Poutnik
    Feb 2 at 18:38
  • $\begingroup$ @KarstenTheis - neat that the calculator keeps up with significant figures. I'm confused though. Based on your input for the container problem it would seem that the answer should have three significant figures. Any idea why the result only has two? $\endgroup$
    – MaxW
    Feb 2 at 22:36
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    $\begingroup$ @MaxW I was puzzled at first, too. I turns out you are subtracting two numbers with 3 significant figures in the numerator, and the subtraction results has two significant figures because the two numbers are similar (like e.g. 50.1 - 48.2 = 1.9). The calculator shows one extra guard digit for the intermediate results, so it is a bit difficult to see what is going on. $\endgroup$ Feb 2 at 23:13
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Updated status: the answer has been restored by the OP and edited to include the calculations. Go check it out, it is an unironically good one.


I suppose it is about Help with two containers problem, Xenon. At the moment, the answer is deleted and is not visible to all users. For the sake of transparency and ease of fact-checking here is a screenshot of the relevant edit I was commenting on:

original answer

as well as the comments section, including the deleted comments:

comments

Help Center provides simple guidelines as to what is expected from an answer (emphasis mine):

Answer the question

Read the question carefully. What, specifically, is the question asking for? Make sure your answer provides that – or a viable alternative. The answer can be “don’t do that”, but it should also include “try this instead”. Any answer that gets the asker going in the right direction is helpful, but do try to mention any limitations, assumptions or simplifications in your answer. Brevity is acceptable, but fuller explanations are better.

Don't you think that the expected full answer for a question

How much Xe do we have to transfer from one container to another so that the pressure in both containers is the same?

would end up with a physical quantity and not a formula?

I agree that

indicated that the answer wasn't good enough.

could be a fair interpretation of my comments, but this was not my intent. The issue I was focusing on was is not that the answer is good or bad; rather, whether it is a complete answer or not.

The answer was overall positively received (4+/0−), and the only drawback was the lack of completeness in terms of providing what's exactly been asked for. The last effort of plugging in the numbers and demonstrating how to handle significant figures would immediately resolve this issue, but instead of correcting the answer OP decided to delete it, the decision which I truly don't understand. Referring to the last comment, it's a shame seeing fish getting off the wise fisherman's hook.

I believe OP acted in good faith and strived for best pedagogical practices, which, I believe, could also be followed by using spoilers for the final answer. Also, since the questioner demonstrated gaps in knowledge of numerical analysis, it would also be beneficial for the them to peep for once the solution to the problem; that is, a competently written one.

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    $\begingroup$ I don't see how taking a dig at me is pertinent. $\endgroup$
    – MaxW
    Feb 1 at 8:22
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    $\begingroup$ I really thought that deriving the formula was an answer. I don't think it is unreasonable for the questioners to do a little work when it will help them understand the problem. $\endgroup$
    – MaxW
    Feb 1 at 8:22
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    $\begingroup$ I'll also point out that it wasn't clear what units the answer was supposed to be in. Grams, moles, final pressures of the two containers? $\endgroup$
    – MaxW
    Feb 1 at 8:23
  • $\begingroup$ @MaxW I didn't mean to take a dig at you, it's just something that's occurring on a regular basis and I wanted to draw your attention towards this post-delete practice one more time. But you are correct, this doesn't belong here. If something about the question is unclear, then one should ask for clarification before answering. That's what the comment section is for. $\endgroup$
    – andselisk Mod
    Feb 1 at 8:36
  • $\begingroup$ As far as the units, I don't think the questioner would have any idea. I'm assuming that the first paragraph was the literal question that the questioner was asked to solve, so the question itself doesn't specify units for the answer. We never know of course in such cases. Is the question posed the real question or the poster's interpretation of the question? $\endgroup$
    – MaxW
    Feb 1 at 9:28
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    $\begingroup$ @MaxW I have updated and undeleted the answer. I have not intended to bring this particular case, but have posted a comment to Meta about balancing of "complete answers policy" and "not to solve complete HW for the OP policy". And also about more detailed guidance about specifics of answering HW questions. $\endgroup$
    – Poutnik
    Feb 1 at 9:59
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    $\begingroup$ Imagine scenario I am a student in the quantum chemistry class and I have a HW task to derive the general wave function for the H atom. I write the Schroedinger equation and some failing attempts to solve it on the CH SE site, asking for the function derivation. Should you as the A author provide to me the complete reasoning and derivation, so I just grab it and give it to the lecturer as my HW done ? Or, should you point out errors, mistakes or misconceptions in my doing for me to be able to succesfully fulfill the HW ? $\endgroup$
    – Poutnik
    Feb 1 at 10:29
  • $\begingroup$ @Poutnik - I think you've given my mental quandary a better perspective. The site doesn't let us characterize responses. We just have a choice between using the "comment field" or an "answer field". I've made what would considered a comment in the answer field and vice versa. I do try to label comments in the answer field as such. Perhaps answers that just try to clear up the conceptual problem should be stipulated as such. I do think that leaving part of the task to the questioner helps solidify the concepts with the questioner. $\endgroup$
    – MaxW
    Feb 1 at 10:55
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    $\begingroup$ I guess I will start applying the trick, asking the OP to reformulate the Q so I could avoid providing the full solution, otherwise I will not answer. $\endgroup$
    – Poutnik
    Feb 2 at 7:59
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Clearly, this question is about a specific answer and a specific case. Let me offer the shortest answer to this specific issue.

The "site consensus" which you seek is laid out in Hint answers revisited. I quote:

Please ensure that your answer contains - at the very least - the final answer to the question, as well as the thought process leading to it.

I think the meaning of this line is clear enough, and I think it also justifies andselisk's point. It is also a stance that I personally (as a user) agree with — after all, that was my meta post.


The followup question is presumably, "how is this the consensus"? Well, we had been debating this issue for a while on meta and in chat. I put it up on meta, and I said that if you disagree please post something. This is how discussions on meta work. It was not an announcement of an impending policy change, it was a proposed policy change. Nobody told me they objected then, so we went ahead with it.

But one should bear in mind that, prior to this, the policy was quite literally the opposite: just give hints, nothing more. And we changed it, based on discussions that were ongoing at that time. This means that it can be changed in the future. The process is simple. If you disagree with it, make a fresh meta post, and the community can decide, by their votes.

I know I personally would not like to change it, but my vote counts for no more than anybody else's; and furthermore, it may not be a bad thing to have a proper discussion on this one specific issue, of whether it is really necessary to plug in the numbers and solve it (as opposed to a broader discussion about "what constitutes a good answer", to which no objective answer can be given, but merely a set of guidelines as Karsten's answer lays out well). As I indicated in the comments, although I personally believe the quoted policy is still applicable here, there is probably some room for debate, because it was not entirely directed at answers like the one here.

The hint answer thing is relevant, but perhaps is being stretched a bit here: it was meant to get rid of completely useless answers, the sort of thing that you might nowadays see in the comment section, e.g. one-liner answers like "HINT: What orbital is the outermost electron in Na in?"

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  • $\begingroup$ No the question wasn't just about the specific case. I was trying to use the case as an example of why I was asking. I could not remember, or find, where in the morass of information on the site where a "good answer" was defined. Moderator andselisk references the "Answer the question" section in the Help Center but that doesn't link to the post "Hint answers revisited." To me that seemed to pluck that meta discussion out of midair. // I'll also point out that you linked that post to the "How to ask a question" post not the "How do I write a good answer?" post. :-( $\endgroup$
    – MaxW
    Feb 3 at 19:48
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    $\begingroup$ "wasn't just about the specific case" Hmm, OK, I kind of interpreted it that way because of your last sentence. I apologise for misunderstanding, although hopefully my answer still addresses that particular point a bit, I guess. "Help Center [...] doesn't link to the post" You're right, unfortunately, I'm not sure if I can edit the help centre text. I know some of it is editable, but this one doesn't seem to be possible. It might be a good idea to consolidate some of this into an FAQ style question which would address the broader issue of what constitutes a good answer. $\endgroup$
    – orthocresol Mod
    Feb 3 at 19:56
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    $\begingroup$ I linked the post to "How to ask a question" - In the "how to ask a Q" post, there's a tiny bit at the end on how to answer homework questions, I think that was the part I had in mind. $\endgroup$
    – orthocresol Mod
    Feb 3 at 19:58
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    $\begingroup$ LOL - The sentence "Isn't plugging in the numbers and calculating a numerical result just mathematics?" was a dig about significant figure questions. I know that they are math questions but the first time students are taught about significant figures is in a chemistry class. To my way of thinking if it is taught in a chemistry class then it is fair to ask about it on this site. $\endgroup$
    – MaxW
    Feb 3 at 20:11
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    $\begingroup$ @MaxW "the first time students are taught about significant figures is in a chemistry class."—in general, no, and it should not be this way, but I guess it depends on the education system. For example, sig figs are explained to us in a math class before chemistry and physics even start, which IMO makes perfect sense since they are inherently an object of study of numerical analysis, a math field. $\endgroup$
    – andselisk Mod
    Feb 4 at 10:09
  • $\begingroup$ @andselisk - My recollection is that the first time I encountered significant figures was in chemistry class. This was the late 1960's in the US. $\endgroup$
    – MaxW
    Feb 4 at 10:13
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    $\begingroup$ I learned about sig figs in college chemistry, as well as other basics such as error propagation, etc. The shortcoming of my own education short not be an excuse for posting any question CSE. Agree with @andselisk. $\endgroup$
    – z1273
    Feb 13 at 15:16
  • $\begingroup$ Until the final formula is written, an answer serves the whole community and the whole class of questions. Since numbers are being plugged in, it serves to a single user in one time manner, with producing the result taking much more time and effort for the responder than is saved for the OP to plug numbers in acalculator or Excel. It is IMHO a demand for inefficient management of voluntary resources, that could be invested in more creative way ( like providing general solution for another question ). Like asking me to go 10 m to pass an OP an apple from a basket laying just before him. $\endgroup$
    – Poutnik
    Feb 17 at 13:50
  • $\begingroup$ P.S.: A question,asking for the numerical result by substituting literal numbers into the general formula should be perhaps closed as "homework without sufficient own effort of the OP". So does the policy requiring numerical result is kind of in conflict with sufficient OP effort policy, that should involve both a priori and a posteriori effort. IMHO, an answer with the ( explained ) general algebraic formula to use IS a complete answer, in sense directly applicable to solve the question. $\endgroup$
    – Poutnik
    Feb 23 at 7:21
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The issue at hand is whether it is always necessary to give complete answers, or whether there is value in getting the OP mostly there, and then leaving it up to the OP to "bring it home".

I personally very much liked Poutink's "teach a man to fish" approach here [1]. In this particular case, I thought the OP was much better served by being provided the equation, and then left to plug in the numbers on their own, rather being provided a complete answer. I.e., I think this OP would have particularly benefited from that exercise. My only suggestion for Poutink would be to have made his pedagogic approach explicit to the OP (or maybe he did this and I'm forgetting), saying something like:

"Here's the equation. I think it would be a good exercise for you to try plugging in the numbers on your own, being careful to both keep track of units and follow the significant figures rules explained in the comments. When you're done, let me know what you get in the comments for the numerator, denominator, and overall, and I'll let you know if it's right or if you need to try again."

Or even just: "I've left it as an exercise for you to plug in the numbers on your own."

Indeed, I've followed that pedagogic approach in some of my own answers. E.g., here I only corrected the error, and indicated to the OP I was leaving it to them to rework the derivation on their own: How is the formula of mean activity coefficient derived?

Granted, the OP only asked that the error be identified, so I suppose you could say this case is different b/c here merely correcting the error did represent a complete answer. But the point is that my philosophical approach was the same as Poutink's.

Here's another instance in which I gave the person guidance on how to figure out the answer on their own, rather than doing all the work for them: Combound with pressure sensitive melting point at moderate temperature and pressure?


MaxW also asks, more broadly: "What is a 'good answer'?" I think the characteristics of a good answer depend on the nature of the question.

If the OP is confused about something, the best answers are those that are able to "see into" the OP's question, determine the essential source of their confusion, and craft an answer that directly addresses that confusion. Often this requires going beyond the OP's literal request, since the OP may not themselves realize the fundamental source of their confusion—i.e., they may be asking about concept A, not realizing the reason they're confused is that they have concept B wrong.

If the question is more general, the best answers are those that, while addressing the OP's request, go beyond that to serve as a nice reference on the subject for the community as a whole.


[1] "Give a man a fish and he can eat for a day. Teach a man to fish and he can spend all day drinking beer."

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  • $\begingroup$ I'll agree that what is a good answer depends on the question and how good the OP thinks the answer is. It seems we should append "Does this answer your question?" to the end of all of our answers. $\endgroup$
    – MaxW
    Feb 5 at 8:56
  • $\begingroup$ @theorist Note that it is Poutnik not Poutink ( more exactly Poutník, from Czech pouť = journey or pilgrimage, related to Russion Sputnik. It could be Poutnik = a wanderer/a pilgrim ). Specifically for EN natives, there is no relation to English verb "to pout". $\endgroup$
    – Poutnik
    Feb 17 at 13:55
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It just snowed in my town, very calming. Everything is covered in a smooth blanket, and life slowed down as folks contemplate staying inside a bit longer before they start shoveling.

Back to the topic at hand.

What is the site consensus on what is a “good answer”?

Mostly, the mechanisms put in place by Stackexchange make it that we don't need a consensus. If the OP of a question gets an answer that is useful to them, they can accept the answer. If they are frustrated with an answer, they can add a comment or edit their question to clarify what they wanted to know and couldn't figure out.

If a third party does not like an answer, they can ignore it, down-vote it, or write their own answer. If they like it but feel it contains a typo, they can fix it or mention it in the comments. Once it is fixed, they can remove the comment.

All nice and calm, like thick snowflakes falling slowly from the sky. And then your neighbor starts the snowblower and throws the snow and slush on your front yard.

When things get a little agitated on this site, it usually involves perceived exploitation of, or disrespect for, the expertise that folks share here voluntarily. I think the best way to answer an interesting question that screams "homework" is not at all, or after the deadline has passed. In the meantime, use the comments to probe what the OP is able to do, and how they could improve their question to make it less "homeworky".

What is the site consensus on what is a “good answer”?

I can say what I feel my best answers accomplish: They answer the question the OP posed, they address all the misconceptions in the question, and they have further reading in the form of links within the site and citations to other sources.

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    $\begingroup$ Karsten you always have given great answers. // I'd quibble about one point. In general it isn't possible to answer homework questions after say two weeks. Either the crowd closes them or currently there is an an admin rush to close such questions. The only way to game the system is to post an answer and delete it. Then you could undelete it after say two weeks. $\endgroup$
    – MaxW
    Feb 2 at 20:45
  • $\begingroup$ @MaxW Thanks for the compliment! Sometimes, I start an answer (without giving the numerical answer) and then get back to it later. This is not always to game the system, sometimes it is just that I run out of time and need to do other things, and then get back to it. $\endgroup$ Feb 2 at 21:55

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