<p>I have a preference for shorter tag names when possible.  That is why I created a tag for <a href="https://stats.stackexchange.com/questions/tagged/rayleigh" class="post-tag" title="show questions tagged &#39;rayleigh&#39;" rel="tag">rayleigh</a>, and not <code>[rayleigh-distribution]</code> (but I didn't really think about it).  </p>

<p>When there are enough questions categorized under a tag, if there is a demonstrated need, we can create additional tags that will further differentiate a category.  As an example, I split up <a href="https://stats.stackexchange.com/questions/tagged/fisher" class="post-tag" title="show questions tagged &#39;fisher&#39;" rel="tag">fisher</a> when it seemed to become problematically heterogeneous (in my mind) and created new tags for <a href="https://stats.stackexchange.com/questions/tagged/fishersexact" class="post-tag" title="show questions tagged &#39;fishersexact&#39;" rel="tag">fishersexact</a>, <a href="https://stats.stackexchange.com/questions/tagged/fisher-information" class="post-tag" title="show questions tagged &#39;fisher-information&#39;" rel="tag">fisher-information</a>, <a href="https://stats.stackexchange.com/questions/tagged/fisher-transform" class="post-tag" title="show questions tagged &#39;fisher-transform&#39;" rel="tag">fisher-transform</a>, <a href="https://stats.stackexchange.com/questions/tagged/ronald-fisher" class="post-tag" title="show questions tagged &#39;ronald-fisher&#39;" rel="tag">ronald-fisher</a>.  I do believe that having the right tags, and having threads tagged appropriately, is very important to the organization and usability of the site.  However, I think think that this will always be a work in progress, requiring some continued maintenance as the site evolves; I don't think it is very possible or useful to try to predict what tags / differentiations will be needed in advance.  For instance, you make a good point about the ambiguity of <a href="https://stats.stackexchange.com/questions/tagged/chi-squared" class="post-tag" title="show questions tagged &#39;chi-squared&#39;" rel="tag">chi-squared</a>, but I haven't noticed an actual problem.  If someone else has, or if one emerges, we could split the tag up.  Until then, I'm inclined to <a href="http://www.youtube.com/watch?v=bKTyd0qy10o" rel="nofollow noreferrer">let it be</a>.  </p>
