<p>Duke is actually # 17 in the US (#18 in North America) according to THES. Columbia is # 13. </p>
<p>Discrepancies apart, I believe THES reflects pretty accurately international perceptions about the relative quality of US universities. Top publics like Berkeley, UCLA or Michigan are indeed perceived overseas to rank higher than the likes of Vanderbilt, Emory, Northwest, WUSTL, Notre Dame Rice, Brown , Dartmouth, or Georgetown. </p>
<p>As for the emphasis on graduate measures (in British English “postgraduate”), it reflects a deep cultural difference between Americans and Europeans. In Europe, the common wisdom is that the strongest a university is in postgraduate research, the better it will be for undergraduates as well.</p>
<p>For example, a high ratio of PhD students to undergraduate students, which, in the view of many American High Schoolers and parents, would be a negative, actually boosts a university’s THES ranking in the ** teaching ** category. Likewise, universities also get extra points in the teaching ranking by awarding a high number of PhDs per year. That is explicitly made in the following quote from the [teaching section](<a href=“World University Rankings 2010-11 methodology | Times Higher Education (THE)”>World University Rankings 2010-11 methodology | Times Higher Education (THE)) in the methodology page:</p>
<p>"* The teaching category also examines the ratio of PhD to bachelor’s degrees awarded by each institution. We believe that institutions with a high density of research students are more knowledge-intensive, and that the presence of an active postgraduate community is a marker of a research-led teaching environment valued by undergraduates and postgraduates alike.*</p>
<p>[…]</p>
<p>* The teaching category also uses data on the number of PhDs awarded by an institution, scaled against its size as measured by the number of academic staff.</p>
<p>As well as giving a sense of how committed an institution is to nurturing the next generation of academics, a high proportion of postgraduate research students also suggests teaching at the highest level that is attractive to graduates and good at developing them. *"</p>