<p><strong>Background:</strong><br>
I saw this answer:
<a href="https://stats.stackexchange.com/questions/188371/negative-population-variable-importance">Negative population variable importance</a></p>

<p>The top line says that the question is a duplicate of one on mathoverflow.</p>

<p>I tried to close-vote it, because it is a duplicate of an answer, but that was not allowed.  It can only be a duplicate of an answer on CV.</p>

<p><strong>Thoughts:</strong><br>
The logical extreme of that is "in all areas of topic overlap between SO communities there must be question replication".  That isn't lean, or efficient.  That sounds like overhead without value.</p>

<p><strong>Question</strong>: What is the source of the policy, and why is it inflexible?</p>
