The Data Science site recently emerged from beta. There's a [data-science] tag on Stack Overflow. I've just added a link to that site in the tag description. SO also has a [statistics] tag which would arguably be a red-flag that the question should have gone to Cross Validated.

Keeping SO pure as a programming/coding site will require migration of even more questions and I'm not seeing a lot of support for that function. I can close SO questions but I cannot migrate them with a single vote. It requires 4 or 5 votes to even move a predominantly statistics question to Cross Validated. That seems excessive.

Leaving it this way seems a burden on the moderators (and to experienced SO users). In the case of the new site that has no migrate-to option in the close panels, I could flag all the "data-sciency" questions (with little programming meat), but I also want to limit the moderator workload.

  • Shouldn't there be better support for warning users of off-topic questions for one site, but the possibility of on-topic-ness on another? This seems especially important for forums where there is a potential overlap of conceptual content

  • Shouldn't the number of votes to migrate be more in line with the number of votes to close?


2 Answers 2


Conventional wisdom on Stack Exchange is that if Topic X becomes on-topic on a site - whether because the site was created or its scope was expanded - then there's no reason for Topic X to be made off-topic on another network site where it was already on-topic. I've seen this firsthand in a couple of cases - notable, Astronomy Stack Exchange, whose questions are by and large on-topic on Physics Stack Exchange. Astronomy SE being created didn't lead to astronomy being removed from Physics's scope, and users who ask on Physics aren't discouraged from posting there. The same principle applies here: If people on Stack Overflow are asking and answering data science questions that are on-topic for SO, there's no reason to move them elsewhere.

It's not a bad idea to point people to Data Science Stack Exchange in the tag wiki, but be careful when you do. Keep a couple things in mind:

  • Don't point them there if you don't know the scope of the site. This irks me a lot about migrations: people not properly knowing the scope of the site they migrate a question to. That's one reason why you can't migrate stuff single-handedly (unless you're a mod); it reduces human error in that regard.
  • If you do mention the site, phrase things so that you note that it's an option to ask there - and users shouldn't feel obligated to do so.
  • Additionally, talk briefly about the scope of the site in the full tag wiki (not just the excerpt). I know that most people don't read tag wikis, but if someone does, and sees that Data Science Stack Exchange is a possibility for them, the least you can do is provide them with some basic information about its scope and the sort of questions they take (and see my first bullet!).

It might be worth asking someone who knows the site for their input on your tag wiki edit, just to make sure you've got it right. It can't hurt.

  • @DWin Ah, I see I phrased that poorly. I've clarified it a bit.
    – HDE 226868
    Commented May 12, 2018 at 2:08
  • If one looks at the questions that have no programming language tag, I'd say many of them were off-topic at least as far as not really being a specific coding problem, but since they didn't have an associated language tag like [r], [python], or [tensor-flow] the people who were focussed on coding in one of those languages never saw the question and it was therefore not closed.
    – DWin
    Commented May 13, 2018 at 21:53

Considering that there are over 1300 open questions with the data science tag on Stack Overflow, I'm not sure that it's fair to say that no data science questions are on topic there. Remember, sites can have overlapping topics. That said, there's a request on Meta Stack Overflow to get rid of the tag entirely:

Burninate the [data-science] tag?

With so many questions using it, though, that takes a lot of teamwork to clear it from existing questions or retag questions that need a better tag to prep for it being removed.

I'm not personally a fan of this but my understanding is that, in some cases, Stack Overflow does do this, such as the history tag, which currently reads:

DO NOT USE THIS TAG. Questions about the history of programming are off-topic. For questions about browser history, use [browser-history] instead. For questions about the JavaScript library, use [history.js]. For questions about the HTML5 API, use [html5-history]. For questions about version control, use [revision-history]. For questions about recalling inputs in an entry box, use [input-history].

That said, there are very good reasons that migrations are limited the way they are. For a migration to go through several things are required, as mentioned in the FAQ for migrations:

  • Don't migrate crap.
    A subject being generally on topic elsewhere doesn't mean that all questions should be move there - only good questions.
  • Question must be less than 60 days old (even for moderators).
  • Questions may only be migrated to sites that have migration paths and each site can only have up to five paths leading away from them. Explanation is here.
  • No migration paths are established to or from Beta sites.
    This is because beta sites are expected to find their own community. A huge influx of questions from an established site will overwhelm a new community and they will be unlikely to manage it. As such, only moderators can migrate to beta sites.
  • Questions must receive at least four votes to migrate (out of five total close votes) in order to be migrated (non-SO sites it's only three).

I'm not quite sure why you think more votes are needed to migrate than to close. Close votes (for any reason other than gold badge duplicate votes) require five close votes. Migrations are a type of close vote. Also, as I said, out of the five close vote slots, only four (on SO) need to be migration votes.

So, please, don't flag stuff that's older than 60 days for migration and avoid flagging huge numbers of things for migration to new beta sites. In the case of Cross Validated, it's possible that many of the questions were already asked there, so migrating large numbers of questions makes more work for them to figure that out. Bulk migrations are extremely rare as the CMs have to do them.

So, if it's one or two new questions and there's a migration target, judge the quality of the question. If it's good, vote to close and migrate to that site. If it's bad, just close the question.

If there's no migration target, and a good question, you can flag for migration. It helps if you know the target site and are able to attest to whether the question would be on topic there or not.

Old questions (older than 60 days) that are off topic on Stack Overflow should just be closed. Trying to migrate them is a waste of everyone's time.

  • Seems [statistics] and [data-mining] might deserve addition to that list, in some form or another.
    – DWin
    Commented May 12, 2018 at 2:48

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