<p>There are <a href="https://stats.stackexchange.com/questions/tagged/meta-analysis" class="post-tag" title="show questions tagged &#39;meta-analysis&#39;" rel="tag">meta-analysis</a>×654 and <a href="https://stats.stackexchange.com/questions/tagged/meta-regression" class="post-tag" title="show questions tagged &#39;meta-regression&#39;" rel="tag">meta-regression</a>×101 tags. Meta-regression is a particular approach to meta-analysis so it's a subset tag. 90 out of 101 Qs are <em>also</em> tagged with [meta-analysis], i.e. there are almost no questions tagged with [meta-regression] only. Given that, do we really need this tag, or should it perhaps be merged into [meta-analysis] (which will only increase the question count there by 11)?</p>

<p>On a related note, I have recently learned that there are fixed effects models, random effects models, and mixed effects models in meta-analysis (see brief but very clear Chapter 2 in <a href="https://www.jstatsoft.org/article/view/v036i03/v36i03.pdf" rel="nofollow noreferrer">https://www.jstatsoft.org/article/view/v036i03/v36i03.pdf</a>). Obviously, people use our [random-effect-model], [fixed-effect-model], and [mixed-model] tags in combination with [meta-analysis], but in fact these models in meta analysis are clearly distinct from mixed models (e.g. you cannot fit them with <code>lmer</code>). Confusing! So I suggest to create tags like <code>[meta-analysis-fixed-effects]</code>, <code>[meta-analysis-random-effects]</code>, and <code>[meta-analysis-mixed-effects]</code> as synonyms of [meta-analysis].</p>

<p>@mdewey wrote me elsewhere that </p>

<blockquote>
  <p>I do not see any pressing need for meta-analysis tagged questions to also have a random effects tag (or fixed effects for that matter)</p>
</blockquote>

<p>which I think is in line with what I suggest (?).</p>

<p>Finally, as far as I could understand "meta-regression" is another name for "mixed effects model in meta-analysis". Which might be another reason to make it a synonym. If not, then alternatively <code>[meta-analysis-mixed-effects]</code> could point to [meta-regression].</p>
