Can we discuss any of the following:

  1. Is there a data set D to do task X?
  2. How can I best clean data set D?
  3. What are some good free data sets?


For the record, asking for data sets is off-topic on CrossValidated, or at least has been marked as such in the past.

  • 1
    $\begingroup$ As cleaning datasets is elementary to Data Science in most cases I would say it's ok. A communitywiki for free data sets would also not be so bad for beginners to find some stuff to play around with. $\endgroup$
    – Johnny000
    May 14, 2014 at 12:28
  • $\begingroup$ Should be fine to an extent. Lets see some questions about them first, before we decide on specifics. $\endgroup$
    – asheeshr
    May 14, 2014 at 13:34
  • 4
    $\begingroup$ But asking for datasets on the [Open Data Stack Exchange][www.opendata.stackexchange.com) is definitely on topic. $\endgroup$ May 16, 2014 at 18:59
  • $\begingroup$ Open Data Stack Exchange $\endgroup$ Sep 26, 2014 at 3:35

2 Answers 2


Of the three examples you give, only the second one ("How can I best clean data set D?") clearly falls within the scope of this site, because it's really about data manipulation.

Questions soliciting recommendations for or links to to data sets are off-topic, not only because there's no data science involved in merely locating a data set, but also by virtue of being perfect questions to ask on a related network site.

Since Open Data is still in the beta phase, this could conceivably change. Migrating questions back and forth between beta sites is something that typically isn't going to happen for reasons discussed in FAQ: Migrations (and more generally, What is migration and how does it work?).

For the time being, it's in our best interest to support both sites in the following ways:

  • Educate users about the scope of this site and the existence of other sites with complementary scope. In other words, comment aggressively and provide relevant links to meta discussions and/or network sites. Don't just tell them they're on the wrong site - tell them where to go and how to get there ("this question is off topic here, but it would be perfect for Open Data").
  • Discourage users from asking out-of-scope questions by flagging to close questions that exist primarily to request data set links and recommendations. And whenever you flag, comment! Closed questions can be reopened if our scope changes.
  • Discourage users from answering out-of-scope questions by downvoting the answers. I know this is a bit controversial while we are in beta; many users are of the opinion that we should hand upvotes out like candy just to pad our stats, thinking "this helps to keep the site going" - but consider that the folks making that decision are neither blind nor stupid. There are plenty of ways to generate page views and build community without sacrificing quality.

I disagree with @Air's answer. Datasets are a basic component of Data Science, there is no Data Science without datasets in the same way that there is no Data Science without Machine Learning. Should we then remove all questions related to Machine Learning and put it in Cross Validated? Should we remove questions related to optimization and add it to Mathematics. It is the same.

I think you are all forgotten the main purpose of this site, and maybe it is because SO don't specifically put it in the titles of the sites. The main purpose is to help people to solve their problems. All the rest is secondary.

If we don't allow to post questions about things strongly related to data science, then we are not helping. If we put many barriers to questions, people will be afraid to ask, we are not helping. If we get crazy about the location of questions or things like what is a perfect question, we are not helping.

Finally, if this place is not for helping people, then SO is really off-topic, and people will to other sites.

NOTE: Right now I'm not sure if I'm allowed to give an opinion (sustained with logical evidences). I might be wrong about this issue, and I know that somebody would argue that in another site there might be a higher change for answers (or maybe not), however, if the matter is deeply related I really think it is more important to focus on answering and helping.

EDIT: I came across this article that explained very well the problem of SO as a community

  • $\begingroup$ "I'm not sure if I'm allowed to give an opinion": You are allowed and even encouraged to do that here :-) For the sake of the argument, let's say I need a particular dataset (for data science purposes), would you recommend me to ask at Open Data or at Data Science? Disclaimer: I am active (top 10) at Open Data. $\endgroup$ May 18, 2016 at 6:13

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