What are the merits, if there is any, of deleting (correctly) answered questions in the main site of MSE?

Question

Note 2: †

This is NOT a duplicate of the linked question: I am NOT asking at all "Under what circumstances is it appropriate to delete a question that has received a good answer?" Again, this post is NOT about when or whether we should delete a question, NO. It is a discussion about the merits of deleting answered questions in the main site.

† Added for responding to a close vote.

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Note 1:

This is NOT a duplicate of the suggested link (Requests for Reopen & Undeletion Votes (volume 07/2018 - today)) at all. While I disagree with the linked questions below being deleted, this post is NOT about voting to undeleting or reopening questions at all, NO!

Rather, I am seeking a general explanation/discussion of why such deletion is (or could be) of value to the main site of MSE.

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[Original question.]

I have noticed recently that quite a lot of answered questions, some of which are still "on-hold", are being deleted by mostly a small group of users in the chat room CRUDE:

• If $p$ is an odd prime and $k$ an integer with $0<k<p-1$ then $1^k + 2^k + \ldots + (p-1)^k$ is divisible by $p$ (now undeleted, 2 deleted votes)

• How many of these lines lie entirely in the interior of the original cube? (now undeleted, 1 close vote)

• how to show that $F(t)$ is a periodic function with period T (now undeleted, 1 deleted vote)
• Counting of natural numbers that have certain properties (now undeleted, 1 close vote)
• IMC 2011 question involving six tangent circles (now undeleted, 1 close vote)

• Find the number of ways to select two balls of different color through combinations (now undeleted, 1 delete vote)

• If $p<q$, then $qx \equiv c \pmod{p}$ has a solution.(deleted)

• Finding an angle in a triangle? (deleted)

I highly doubt the justification of such deletion since it makes others' work (mostly) disappear. A (very) high-rep user (now no longer active) had a similar concern for such action before:

Is there an MSE-like site that is more pleasant to work in? Or are there other solutions?

Question:

What are the merits, if there is any, of deleting (correctly) answered questions in the main site of MSE?

Answer 1

Deletion sends a rather clear message that the content is not welcome. To send this message is a merit of deletion. By contrast to put on hold/close yet not delete does not achieve much especially for answered questions.

Of course, one might think that the content is or should be welcome, but that would be a separate concern. If one wishes to discuss this, then one should start a step earlier namely question the closures.

Answer 2

Promoting some of the comments to an answer so that users can vote on them more freely. I got the impression that at least the OP wanted this to happen. As this is somewhat independent from my longer answer, I want to give the voters the chance to agree/disagree with some parts of what I wanted to say while being indifferent to, or even feeling the opposite way about the other post.

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I agree with quid's point in that the merit of deletions is to send a loud and clear message that this content is not welcome. I want to emphasize and clarify that, at least for me, the recipients of that message are the answerers:

• Answering a duplicate question does not add new content to the site, but it does add more entropy. This is a net loss, and I want to discourage the practice. I am on record (in meta) for being militantly anti-dupe, so I don't want to repeat it all.
• Answering a copy/pasted homework problem invites more of the same, and gives the site a bad reputation as a homework mill. Also, the same assignment was used in the same course a year earlier, so it is often also a duplicate. I want to discourage both asking and answering this type of questions.

Simply closing the questions does not discourage any of the above practices. All the closed posts can still be voted on. The same applies to duplicates. Deletion is the only sufficient deterrent at my disposal. And also hitting the answerer is exactly my goal.

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But, let's not forget that

• Duplicates are sometimes hard to find. I really should do a better job not making this message personal. A biblical parable involving a beam and a mote springs to mind also.
• I want to commend our moderators, and confess that once this fight against dupes/low quality content became too personal for me, and they had to send me a private reminder/warning not to do that.
• I do believe that not all the answerers of LQ questions are in it for the sake of internet points. Yet, when the same names recur as answerers to questions in a close/delete queue I have a hard time A) remembering this, B) believing their excuses. We can blame the gamification aspects of the site for many a bad thing. But, SE wants us to play, so it is not unnatural to ask for a level playing field.

Answer 3

The site norms about this have gradually changed over the years, so it may be helpful to take a bit of "historical" look at the problem. I think it sheds some additional light. Also, I try to explain how the scale, more precisely, the growth of the site also plays a role.

StackOverflow is a couple of years older than us, and an order of magnitude bigger. So it may be a good idea to link to a few posts I find relevant. Both the posts I want to encourage you to read were written by Shog9 - one of the community managers working for StackExchange. He has extensive understanding of the dynamics of these sites (it's his job). He is also one of the CMs who regularly interacts with Math.SE moderators, and, when needed, will post here.

You are welcome to think that I am horribly misrepresenting his points. I probably am. You see, he is using metaphors necessarily open to interpretation. See for yourselves. His older post and a more recent one. I probably shouldn't try my hand using an agricultural metaphor, but I will do it anyway :-) You can have a field day (bad pun intended) breaking my metaphor. It will do just that. Probably faster than I expect it to.

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In its infancy this site did not have this problem. There was room for everything. Nearly all the content was new. The users were not unlike happy gardeners in a paradise. Some wanted to nurture rare orchids, some wanted to concentrate on farming food. Yet, everything was small scale. If a weed showed up, we had the resources to study it carefully. Painstakingly isolate it from the wheat and the orchids, try and mutate it to something more interesting. Failing that we would uproot it, by hand, so as not to disturb the plants near by. Some did not want to participate in that kind of gardening, but that was tolerated, because dealing with the weeds was not too time consuming.

When the site started growing, problems started appearing. Some would have liked to continue doing what they had always done. Others pointed out the benefits of crop rotation, pointing out that monocropping depletes the soil of some nutrients, making it less fertile for seasons to come, and also making it easier for pests to appear. Fights broke out. In the end some kind of a truce was reached. Even though there was some collateral damage, we still had enough resources to protect some of the useful plants that happened to be close to a weed.

But the site kept growing. Needing to feed a lot of people, we, almost without noticing exactly when the change happened, switched to intensive farming. We still want to do crop rotation. But, the scale has gone up. We no longer have the resources to carefully examine each and every plant by hand. Says Wikipedia: It takes very few wild oat plants to cause a significant reduction in the yield of a wheat or cultivated oat field, even though the seeds are a type of oat. So when we spot a few wild oat plants, severe collateral damage will be necessary. The farmer happily sacrifices many good stalks to make sure all the wild oats are destroyed. Whatever it takes to save the main crop.

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So that's why many deletions in the current stage of the development of the site are IMHO necessary.

• The questions may be monocropping duplicates, or pests of attempts to outsource homework.
• Both of those must be stopped, for they will invite their "friends" to crash the party. If the price we have to pay is the destruction of a few correct answers, so be it.

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But, that's not the end of it. What lies in the future? Reread Shog9's later post. Water. If we don't accommodate for it, it will destroy the farm. And. Water. Does. Not. Care. What/who is water here? Many interpretations are possible. His most important message may be (my interpretation) that we all need to brace for a future when we ALL need to compromise on some of our dearest principles. Linking to the infamous post describing four types of SE users

1. The librarians may be forced to accept that they cannot have full control of the content. Some may leave the site in disgust, but do observe that the librarians will get reinforcements from the ranks of former prolific answerers.
2. The noobs will also need to learn the site norms. But, the continued existence of the site needs new users. Many a noob will inadvertently start out as one of this type. But we need many of them to stay.
3. The most knowledgable of the noobs will become prolific answerers. If left to themselves usually not adding new content. So they will need to learn to compromise. And, in the end, they will be converted to librarians (seen this happen a few times already)...
4. ... or possibly to an apathic shaking their head on the sidelines (this fate awaits a few librarians also).

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But, while all this played out, there was the hermit, happily tending to a few orchids. Not worrying about the ego points and politics. Just beautiful math. Very Zen (unless somebody steps on his orchids).

Answer 4

My opinion, lifted from some comments I wrote above. It is not solving the problem, but arguing that the current approach to said problem is misguided.

I will develop my argumentation by building on two comments left by @postmortes (comments I disagree with), who wrote

"[I think] that's what the debate is about: whether this really is a site to get your homework done for you"

and

"If the site isn't about getting your homework done then it will be hard for anyone to argue that PSQs shouldn't be deleted."

Indeed, we are talking about past, already answered PSQs, not new ones. The debate is rather

Is deleting those past, answered, closed questions an efficient way to prevent new ones (PSQs, HW, etc) appearing?

And I don't think the answer is that clear. Namely:

• The OPs of those closed, answered questions were usually first-time posters; were either discouraged by the response (closure) or got what they want, and are probably not coming back anyway: so it won't affect them.

• Newcomers won't see the deleted questions, so won't learn from their closure/erasure.

So it doesn't deter the posters. The only possible argument is then that it will deter the answerers from answering those poor-quality undesirable questions in the future. Right?

But that's penalizing said answerers for things they answered 5 months or even 5 years ago! I really doubt this will have the desired effect. Instead of changing their future behavior, that might just (understandably, if you ask me) piss them off and drive them away — and thus also lead to fewer good answers on good questions.

So you end up with less valuable content (which in many case was good quality, even though the questions were not), and fewer of the previous answerers willing to contribute to good content in the future. Maybe I'm pessimistic, but that does not seem like a sound policy to implement.