<p>Recently I have been reading quite a lot on CV about fixed / random / mixed effects models and related terminological controversies. Unfortunately, the CV tags for the mixed models are a mess, which does not help navigating the questions (which is a pity, given that the topic is confusing enough).</p>

<p>Namely, there is <a href="https://stats.stackexchange.com/questions/tagged/mixed-model" class="post-tag" title="show questions tagged &#39;mixed-model&#39;" rel="tag">mixed-model</a> tag (<strike>689</strike> 1214 questions, nice wiki),  <a href="https://stats.stackexchange.com/questions/tagged/mixed-effect" class="post-tag" title="show questions tagged &#39;mixed-effect&#39;" rel="tag">mixed-effect</a> tag (<strike>95</strike> 305 questions, worse wiki), and also <a href="https://stats.stackexchange.com/questions/tagged/mixed" class="post-tag" title="show questions tagged &#39;mixed&#39;" rel="tag">mixed</a> tag (<strike>28</strike> 61 questions, no wiki). I do know that terms <em>fixed</em> and <em>random</em> are used differently by different people, but as far as I understand, mixed is mixed. So I think these three tags should be merged.</p>

<p><strong>I think the master tag should be <a href="https://stats.stackexchange.com/questions/tagged/mixed-model" class="post-tag" title="show questions tagged &#39;mixed-model&#39;" rel="tag">mixed-model</a>, and the other two can be merged into it.</strong></p>

<p>The two related tags are called <a href="https://stats.stackexchange.com/questions/tagged/random-effects-model" class="post-tag" title="show questions tagged &#39;random-effects-model&#39;" rel="tag">random-effects-model</a> and <a href="https://stats.stackexchange.com/questions/tagged/fixed-effects-model" class="post-tag" title="show questions tagged &#39;fixed-effects-model&#39;" rel="tag">fixed-effects-model</a>, so originally I wrote here that the best name for the merged tag would be <code>[mixed-effects-model]</code> (which currently does not exist at all); however, on reflection, "mixed model" <a href="https://en.wikipedia.org/wiki/Mixed_model" rel="nofollow noreferrer">seems to be</a> a more standard terminology.</p>

<hr>

<p>This issue was brought up multiple times on Meta, but stays unresolved. </p>

<ul>
<li><p><a href="https://stats.meta.stackexchange.com/questions/1200/current-tag-synonym-candidates/1969">Here</a> I suggested the same thing yesterday and @gung commented that it seems reasonable.</p></li>
<li><p>In 2012 <a href="https://stats.meta.stackexchange.com/questions/1369/redundant-tags-mixed-effects-and-related-models">a bunch of related tags</a> was discussed with the same suggestion about "mixed" tags, and I can see no counter-arguments in the discussion (even in the careful reply of @StasK).</p></li>
<li><p>In 2011 <a href="https://stats.meta.stackexchange.com/questions/890/should-mixed-model-and-multilevel-analysis-be-tag-synonyms">a related question was asked</a>, and @chl reported in the comments that he merged [mixed-model] and [mixed-effects-model] (the latter tag does not exist anymore).</p></li>
<li><p>In 2013 @Randel left a comment in the above thread suggesting the same thing as I do here, and @AndyW and @chl agreed.</p></li>
</ul>
