<p>The rules vary from college to college. For the ones you list:</p>
<p>Penn: requires all tests (SATs, SAT IIs and ACTs)</p>
<p>Cornell: requires all SATs and all SAT IIs; requires all ACTs if you submit any ACTs</p>
<p>Yale: requires either all SATs and SAT IIs or, alternatively, all ACTs (it accepts ACT in lieu of both SAT and SAT IIs)</p>
<p>Harvard, Princeton, Dartmouth, Brown, Columbia: accept score choice for all tests (SAT, ACT and SAT IIs)</p>
<p>NYU, USC, MIT, Gtech, UT (Austin), UVA, Michigan, Chicago, : accepts score choice for all tests </p>
<p>Carnegie Mellon: requires all SATs, or alternatively, all ACTs (if you submit both tests, all tests must be submitted); and then requires all SAT IIs if particular CMU college requires SAT IIs (not all the CMU colleges require SAT IIs)</p>
<p>UC Berkeley, UCLA: current rule is ambiguous. It requires all SATs if you send any one SAT but unclear whether that rule applies to ACT or SAT IIs</p>
<p>Stanford: requires both all SATs and all ACTs but you can send whatever SAT IIs you want to send</p>
<p>Caltech: accepts score choice for all tests but “strongly recommends” submitting all SAT and SAT II scores (many other colleges usually just say recommend rather than strongly recommend submitting all scores)</p>
<p>UIUC and University of Washington: accept score choice for SAT and ACT and do not use SAT IIs for admission. </p>