   3        0        1
## 5     2  30.58     4        1        1</code></pre>
<p>We can specify models with <em>time-dependent covariates</em> using exactly the same syntax as for models with time-constant covariates, as in the previous section.</p>
<p><strong>Key assumption</strong>: <code>msm</code> will assume that the covariate value is <em>constant between observations</em>.</p>
<p>This defines a <em>time-inhomogeneous</em> Markov model, with <em>piecewise constant</em> intensities.</p>
<div id="predic