n AFDC</p></li>
<li><p><strong>d90:</strong> =1 if year == 1990</p></li>
<li><p><strong>lpcinc:</strong> log of pcinc</p></li>
<li><p><strong>cafdcprc:</strong> change in afdcprc</p></li>
<li><p><strong>clpcinc:</strong> change in lpcinc</p></li>
<li><p><strong>lphysic:</strong> log of physic</p></li>
<li><p><strong>clphysic:</strong> change in lphysic</p></li>
<li><p><strong>clowbrth:</strong> change in lowbrth</p></li>
<li><p><strong>cinfmort:</strong> change in infmort</p></li>
<li><p><strong>afdcpay:</s