      O13 | d1*t1</span></span>
<span><span class="st">      O3  | d2*t2</span></span>
<span><span class="st">      O8  | d3*t2</span></span>
<span><span class="st">      O28 | (-0.5)*t1</span></span>
<span><span class="st">         "</span></span>
<span><span class="co"># estimate model in mirt</span></span>
<span><span class="va">res</span> <span class="op">&lt;-</span> <span class="fu">sirt</span><span class="fu">::</span><span class="fu">lavaan2mirt</span><span class="op">(</span> <span class="va">dat</