<p><em>(Note this previous, related discussion: <a href="https://stats.meta.stackexchange.com/q/1369/7290">Redundant tags: mixed effects and related models</a>.)</em>  </p>

<p>The <a href="https://stats.stackexchange.com/questions/tagged/hierarchical" class="post-tag" title="show questions tagged &#39;hierarchical&#39;" rel="tag">hierarchical</a> tag is very ambiguous.  Unfortunately, this hasn't been addressed before and it now has 142 questions.  An excerpt was just suggested:  </p>

<blockquote>
  <p>For questions about hierarchical models, also called multi-level models.  </p>
</blockquote>

<p>However, it isn't at all clear that that's what the threads grouped under this tag are about.  (It isn't clear they are consistently about anything.)  For example, <a href="https://stats.stackexchange.com/search?q=%5Bhierarchical%5D%20clustering%20is%3Aquestion">at least 33 are about clustering</a>.  </p>

<p>I'm wondering what we should do about this.  It really seems to be a mess.  Some options might be: retagging, making synonyms and/or merging, or deleting.  </p>
