owest level of hierarchy and move upwards (in this case <code>classid:schoolid</code>, followed by <code>schoolid</code>). Grouping factors in <code>nlme</code> are given starting at the highest grouping and move down (<code>schoolid</code>, followed by <code>classid</code>). The order of <code>classid</code> and <code>schoolid</code> in the returned tibble is based on these conventions.</p>
<p>To extract the classroom-level random effects for <code>fm2.lmer</code>, we set <code>level = "classid:schoolid"</