<p>A week ago @JuhoKokkala raised the following Meta question: <a href="https://stats.meta.stackexchange.com/questions/4266">Ambiguous [combination]&#160;tag</a> -- and the consesus was that [combination] tag should be entirely removed and replaced by [combinatorics] where necessary. (Update: This has been done by now.)</p>

<p>There is a conceptually related <a href="https://stats.stackexchange.com/questions/tagged/permutation" class="post-tag" title="show questions tagged &#39;permutation&#39;" rel="tag">permutation</a> tag (261 threads) which is mostly used to refer to permutation-based hypothesis tests, but sometimes refers to combinatoric problems related to permutations. I don't think this lumping is helpful.</p>

<p><strong>Proposed step-by-step solution</strong></p>

<ol>
<li><p>Create <a href="https://stats.stackexchange.com/questions/tagged/permutation-test" class="post-tag" title="show questions tagged &#39;permutation-test&#39;" rel="tag">permutation-test</a> tag and tag a couple of most important related threads with it.</p></li>
<li><p>Go through all [permutation] threads and remove the tag from all non-permutation-test-related questions, replacing with <a href="https://stats.stackexchange.com/questions/tagged/combinatorics" class="post-tag" title="show questions tagged &#39;combinatorics&#39;" rel="tag">combinatorics</a> where necessary.</p></li>
<li><p>After that, merge [permutation] into [permutation-test]. (This will affect at least 150 threads, so it's better to do it automatically via the merge).</p></li>
<li><p>Delete the [permutation] tag as confusing (i.e. delete the synonym mapping).</p></li>
</ol>

<p><strong>Update (Feb 22):</strong> All done.</p>
