Over time, a large number of machine learning questions have been asked and answered on Stack Overflow, amassing a significant amount of useful information. However, these questions are unfortunately off-topic for Stack Overflow, and as they come to members' attention, they are being closed (SO is for implementation questions, not theory). For example:

There are many more similar questions that are likely to be on the chopping block as mods get to them. And I'd really hate to lose the ability to have experts add new answers to them (or for them to be silently deleted if someone got overzealous without anyone noticing).

Unfortunately, there's a 60 day limit on migrating questions between sites. Moderators can't even override this, only SE employees can. This is for good reasons, smaller stacks didn't want StackOverflow dumping a backlog of terrible questions on small sites with even fewer moderation resources, or for bad questions to get passed around like White Elephants from stack to stack. Additionally, high-rep users on smaller stacks were rightfully upset that one migrated question from a big stack could shoot a member that never participated in their stack to the top of their rep ladders (and occasionally, vice versa).

This leaves SO in a difficult situation. Close the questions and let these questions stagnate? Delete them and hope the vacuum promotes similar questions to be asked on the correct stacks? Leave them open and set a bad precedent for newer theory questions (that should probably be asked here?)

I have two other possible solutions, but either would require the buy-in of the receiving stack. And I'm pretty sure the rightful home of most of these questions is here on Cross Validated.

  1. Nominate a large block of well-maintained theory questions, link them here on stats.meta, get approval from CV members, then bring the list to se.meta and beg for migration.


    • easier on mods, users, and google algorithms (which would be directed here instead of SO)
    • high-rep questions getting migrated might distort the rep landscape of CV
    • consensus on many questions is difficult to get simultaneously
    • after all that effort, se.meta might just say no or leave it in limbo forever.
  2. Manually copy "good" ML theory questions and answers from SO to CV when they are closed, and then ask for SO mods to add a redirect link here.


    • Many of these old questions are asked/answered by users that may have not been active for years, so requesting reposts from them is likely a fool's errand.
    • Manually "cross-posting" would be quite a lot of manual work, so it wouldn't be undertaken for anything but the most worthy Q&A's
    • CV users can judge their worth for themselves and up/down/close vote as appropriate
    • If I were to do this, I'd ask the mods to make both question and answer Community Wiki, because honestly I don't want to leech rep from work I didn't do. That is a controversial method, but personally, I'd rather err on the side of not taking credit for other's work.

I personally lean towards 2, although 1 would put most of the work on SE employee's shoulders (which the lazy slob in me likes) and bring more traffic here form Google (which may be a dubious benefit). But either would depend on buy-in from CV members and mods. So what do you think?

EDIT: After some delay, I've started closing questions on SO for this purpose. It would be helpful to have CV mods chime in on the MSO answer here for clarification on disputed questions (whether they are on-topic here, or may be on-topic elsewhere, like Data Science or AI)


2 Answers 2


They should be migrated here! Already two comments prefer option 1) so that looks a good one.

  • $\begingroup$ According to @CodyGray over on SO, it should simply be a matter of a CV mod requesting migration of a closed SO question to a Community Manager. There is some backlog of worthy candidates on SO that haven't been closed yet, so SO would probably want to do a concerted push to close them and then have a second wave later if this group works. $\endgroup$
    – Daniel F
    Jan 27, 2021 at 18:12
  • 1
    $\begingroup$ @Daniel F: Could you start the making of such a list? It could be made either here, or maybe better at the SO Meta, and then others could contribute to the list when it is started ... $\endgroup$ Jan 27, 2021 at 22:25
  • 2
    $\begingroup$ I've asked a question on MSO here $\endgroup$
    – Daniel F
    Jan 28, 2021 at 11:57
  • $\begingroup$ Is there any concern from the CV mods that the 3rd and 4th questions are more opinion-based? $\endgroup$
    – Daniel F
    Jan 29, 2021 at 8:30

I wanted to raise on of the concerns from the MSO question - the issue of duplicates.


Is there agreement that in these cases, if one is duplicate-targeted of the other, that the questions would get reciprocal links (say, a note and "see also" link at the top of the canonical pointing towards the dupe) and a historical lock, or be merged?

There is concern that the questions might be more likely to be deleted here if they get dupe-closed than if they got off-topic closed on SO, especially if the scores are reset.

  • 13
    $\begingroup$ We almost never delete in cases like that. It's possible that they are merged, but that's not very common, either. Even if one of them were closed (which isn't actually guaranteed), it would be better to have them both here & cross-linked to each other, IMO. $\endgroup$ Jan 29, 2021 at 12:55

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