<p>I think the question is getting ahead of things.  I think the first thing you should figure out is: where are RL questions most likely to get the best answer?  That's not clear to me.  I suspect it is likely to depend on the specific question.</p>
<p>The statistics that 19% of questions on AI.SE are about RL and 0.5% of questions on Stats.SE are about RL don't seem relevant to me.  That tells me little about whether any particular question is more likely to get a good answer here or there.</p>
<p>A statistic that <em>might</em> be more relevant is what fraction of questions on RL are answered, on AI.SE and on Stats.SE.  When <a href="https://stats.meta.stackexchange.com/a/5574/2921">Scortchi did that analysis two years ago</a>, the results were apparently that approximately 58% on Stats.SE were answered and 75% on AI.SE were answered.  There are some major caveats, though.  For instance, it doesn't measure what fraction received a good answer, and doesn't take into account whether those are a similar population of questions.</p>
<p>I think a more fruitful way to advance the conversation would be through further data and analysis.  For instance, are there some categories of RL questions that are more likely to get a good answer on AI.SE than on Stats.SE?  Can you gather any data on it, by taking a random sample of 20 such questions on both sites and rating how many received a good answer?  That might yield some advice to question-askers that could be useful.</p>
<p>I would be skeptical of a proposal to declare RL off-topic here and direct all such questions to AI.SE.  <em>If</em> there was sufficient evidence or consensus, it's possible that there might be utility to some general (non-binding) advice that says &quot;if your question meets these criteria, then it might do better here, if it meets those criteria, it might do better on AI.SE&quot; and leaves it up to askers where is best suited for them.  But that would need to be developed and fleshed out further.</p>
<p>I would also encourage you to look for policies that might be a win-win for all sites.  Proposing a site policy that appears to benefit one site at the cost of another site does not appear likely to succeed.  Since you raised the idea of collaboration, I like to think of &quot;collaboration&quot; as a project that everyone involved views as to their mutual benefit.</p>
<p>I suspect that part of the challenge is that there is considerable overlap in topic areas between folks who work on statistics, computer science, data science, and AI.  So, for some subjects, you have multiple communities of people who each have their own perspective and approach to the subject.  That might admit any simple bright-line solution involving pushing all such questions to one site or the other.</p>
