<p>
I would much rather be in a massive lecture hall with a really good lecturer than in a small class with a bad one. A more important metric might be the availability of office hours, but I don’t think this has been measured.</p>
<p>The Oxbridge schools are very impressive. In addition to the interview, I know that the Cambridge mathematics department (usually considered the best in the world) utilizes STEP tests for conditional offers. Look at a few of the practice booklets:</p>
<p><a href=“http://www.admissionstests.cambridgeassessment.org.uk/adt/digitalAssets/110501_Advanced_Problems_in_Mathematics.pdf[/url]”>http://www.admissionstests.cambridgeassessment.org.uk/adt/digitalAssets/110501_Advanced_Problems_in_Mathematics.pdf</a>
<a href=“http://www.admissionstests.cambridgeassessment.org.uk/adt/digitalAssets/112161_Advanced_Problems_in_Core_Mathematics.pdf[/url]”>http://www.admissionstests.cambridgeassessment.org.uk/adt/digitalAssets/112161_Advanced_Problems_in_Core_Mathematics.pdf</a></p>
<p>This is certainly a more useful entrance exam than the SAT Math IIC Subject Test.</p>