  <th>group.effect</th>
      <td><p>The magnitudes of person group effect  (in logits) for Group 0 and Group 1, respectively.</p></td>
    </tr>
    <tr>
      <th>itemtype.effect</th>
      <td><p>The magnitudes of item type effect (in logits) for itemtype 0 and item type 1, respectively.</p></td>
    </tr>
    <tr>
      <th>dif</th>
      <td><p>The magnitude of differential item functioning (DIF) for the items. Either a single value to create DIF
for all items or a vector with the length of nitem that 