<p>Read this</a> article and this</a> article to see why Caltech came out on top in 1999 and doesn't anymore. Basically, before 1999, U.S. News used a system that was questionable from a statistical point of view to make sure Harvard, Yale, and Princeton came out on top. In 1999, they had the statisticians devise a new, more accurate one. As it turned out, the difference between Caltech and the #2 school was "seven points (more than the difference between #2 and #8)." To make sure Caltech wouldn't come on top again after 1999, U.S. News decided to apply a logarithmic adjuster to only to categories where Caltech had a huge advantage of HYP.</p>
<p>All this applies only to the undergraduate schools rankings, but still, it's interesting to keep in mind.</p>