<p>Have you ever wondered what <a href="https://stats.stackexchange.com/questions/tagged/population-average" class="post-tag" title="show questions tagged &#39;population-average&#39;" rel="tag">population-average</a> is about..? If not, check its info page</p>

<blockquote>
  <p>Population average model assesses the association between X and Y
  based on averaging over the random effects, rather than the one for an
  individual subject (subject specific model).</p>
</blockquote>

<p>Somehow it does not surprise me that it is not used for such questions... </p>
