50% seems really high. At my school, we usually lose 1, maybe 2, people per class. While it is true that people that will drop seem to do so in the first year, I have found that the second year tends to be the most academically challenging (Capstone work and lack of intro classes). I would think that a lot of people drop not for academic reasons, but because they start to learn more about Audiology and change there minds. Both of the people who dropped from last years class did so in order to pursue a different profession.