pan class="op">(</span> <span class="va">dat</span><span class="op">[</span>,<span class="fl">1</span><span class="op">:</span><span class="fl">6</span><span class="op">]</span>, <span class="va">mirtmodel</span>, itemtype<span class="op">=</span><span class="st">"gpcm"</span>, pars<span class="op">=</span><span class="st">"values"</span><span class="op">)</span></span>
<span><span class="co"># fix slope of item O28 to 1.2</span></span>
<span><span class="va">ind</span> <span class="op">&lt;-</span> <span c