I think the distinction between public and ivy here may be data noise. If you scroll down to the chart that compares ivies and public by subject, you'll see tha

I think the distinction between public and ivy here may be data noise. If you scroll down to the chart that compares ivies and public by subject, you'll see that in political science courses, Leviathan is the most assigned book in both public and elite colleges, but there are ~250 instances for ivy and < 100 for public. So for some reason there are lots more political science syllabi in the Ivy data set than the public one, which would skew the overall results. TBH, though, I can't really make any sense of this data. The overall result says that Leviathan appears just over 200 times overall at Ivies (i.e. fewer times than in Ivy poli sci syllabi). And for most assigned business books, "Asking the Right Questions" appears 450 times, which should put it at the top overall, but it doesn't appear in the top 10.