According to US News, in 2000 Tufts had 5,513 applications, interviewed 811 for 168 spots, but actually accepted 460 (you're right, over 50%). This seems like it is because many people who are accepted don't go there for one reason or another. Personally, it would be pretty low on my list because of cost, so if I were accepted somewhere else, I would likely turn down Tufts. Tufts is a good school, but not that good. 🙂