<p>I think that this would depend on the question being asked. If someone is looking for a data manipulation package like <code>plyr</code> for example, I would think that would be a SO question. </p>

<p>But if the question is more about how to implement a particular model in R, then surely this is straightforwardly a statistics question? R, as with any programming language, can be used for things other than statistics - I presume this is why general programming questions are referred away to SO. But if the question relates to doing statistics <em>IN</em> R, I would think that this fell within the purview of this site. </p>

<p>Whether there is a particular package that implements the model directly or it has to be implemented by hand probably shouldn't be used to discriminate which questions should go where. Equally, I don't think that model implementation questions should be removed from Cross Validated either, because that would reduce its usefulness substantially to practitioners.</p>

<p>The major factor to consider here is probably more around question quality and whether the person has made an effort to do their own <a href="https://stats.stackexchange.com/help/quality-standards-error">research on the subject</a>. If there is no evidence that they have made an effort, then the question probably contravenes other rules around question quality and can be closed on that basis.</p>
