<p>I'm not sure what the right approach is in this case (and there are a few similar cases in other tags).</p>

<p>The tag <a href="https://stats.stackexchange.com/questions/tagged/pivot"><code>pivot</code></a> seems to be being used for both 'pivotal quantities' and 'pivot tables' (as in Excel). The first use of it seems to have been related to pivotal quantities, but it's been used about equally for both. </p>

<p>As such, I think the 'find similar questions' use of tags is somewhat compromised, since half the 'pivot' hits you will get will be the other meaning. </p>

<p>Might it make more sense to set up 'pivotal-quantity' and 'pivot-table' tags and edit so that the two are separated (perhaps making pivot a synonym of one of them)? </p>

<p>That would, of course, involve editing the tags on the existing questions with the tag.</p>

<p>On the other hand, it's not a heavily used tag (11 times I think), so perhaps its okay to just leave it.</p>

<p>I'm not sure what the reasonable thing to do is, so I figured I'd ask.</p>

<p>---</p>

<p>Edit: Taking into account @gung's concern about large scale changes to tags being disruptive, here's my plan:</p>

<p>1) Right now -</p>

<p>a) give the ~half-dozen questions that have the <code>pivot</code> tag but aren't about pivotal quantities have the <code>pivot-table</code> tag (thus changing only about five or six tags at once)  [<em>done</em>]</p>

<p>b) make a tag wiki for <code>pivot</code> to say it's for <em>pivotal quantities</em> and mentioning the existence of the <code>pivot-table</code> tag [<em>done</em>]</p>

<p>c) make a tag wiki for <code>pivot-table</code> [<em>done</em>]</p>

<p>(at this point, the tag situation is 'stable' in the sense that it's clear to users what to do, if somewhat imperfect)</p>

<p>--</p>

<p><strong>In the future</strong> (if needed)</p>

<p>2) At some time later on -</p>

<p>a) make a <code>pivotal-quantity</code> tag</p>

<p>b) make a tag-wiki for it</p>

<p>c) edit tags on the remaining ~5-6 posts to make it <code>pivotal-quantity</code></p>

<p>d) edit the <code>pivot</code> tag wiki to mention the use of the other two tags</p>

<p>e) reserve the <code>pivot</code> tag for <em>pivoting</em> in the <a href="http://en.wikipedia.org/wiki/Pivot_element" rel="nofollow noreferrer">matrix calculation</a> (Gaussian elimination etc) sense, and perhaps the <em>pivot</em>-element in quicksort sense, both of which have some relevance to statistics (but retaining the note about the other two tags)</p>

<p>OR</p>

<p>3) Alternative to (2) if <code>pivot</code> becomes widely used and the matrix sense is needed -</p>

<p>a) make a <code>pivot-element</code> tag</p>

<p>b) make a tag-wiki for it</p>

<p>c) edit tags on any <code>pivot</code> posts that should have this tag instead</p>

<p>d) edit the <code>pivot</code> tag wiki to also mention the use of the new tag</p>

<p>--</p>

<p>* Edit2: In carrying out stage 1, I struck the following quandary - <a href="https://stats.stackexchange.com/questions/12901/tracking-problem-with-a-formula">This post</a> is tagged as <code>pivot</code> ... and at first glance I had thought it was connected to <code>pivot-tables</code>, but now I am not at all sure it is. In fact I can't work out how the term <code>pivot</code> comes into it at all. Should it be retagged as some other kind of thing? [<em>Fixed by @gung</em>]</p>
