Do reviewers usually ask for data? (Computer Science/ Data Science / Data Mining) I know it's a free process and it depends on reviewer if they want the data and for author if they want to submit it.

Questions:


What are the chances of a reviewer asking for data?
Why might reviewers ask for data?
I have asked, or been asked, for data a vanishingly small but non-zero number of times. But I'm pretty secure in asserting that it's rare.

As for why - I would hope they would specify this when they requested it. Among the reasons would be to see if your results are genuinely obtainable from your methods. This is not necessarily just looking for fraud, etc. but checking to see if your writing is clear enough that by "following the recipe" they get the same answer.

Another possibility is they want to try an alternative analysis. For example, in my field, there is a variable selection method that is commonly used and also wrong. Generally, I ask authors to re-do their analysis with a more appropriate method as a reviewer, but it's entirely possible this won't change the answer. Having the data would let me check for myself.