Since the professorial field is overwhelmingly liberal Democrat, these findings are worthy of an eye roll and nothing more. Anyone who thinks Bill Clinton was a better President than Ronald Reagan needs their head examined. Obama in the top 15? Lol.
Or maybe they're more likely to be liberal because they know and understand history, whereas conservatives are, as the old saying goes, just doomed to repeat it?
So only liberals can interpret history correctly? Hmm, I guess you're right, except when it comes to economics, war, and most social issues.
I think the best judges of presidential performance are the people, not an ivory tower clique of Marxist professors. If you seriously think that Obama should be ranked #15 (now or ever) you need serious counseling.