="cb105-3"><a href="timedep.html#cb105-3" aria-hidden="true" tabindex="-1"></a>                ...</span>
<span id="cb105-4"><a href="timedep.html#cb105-4" aria-hidden="true" tabindex="-1"></a>)</span></code></pre></div>
<p>Again this assumes that the <code>months</code> covariate is constant between each person’s visit.</p>
<p>But we may want to express a model with</p>
<ul>
<li><p>constant intensities within particular time periods (0-6, 6-12 months)</p></li>
<li><p>hence the intensity <em>changes for e