They look at performance in the interview, performance on the sim check, performance in ground school, performance in aircraft specific training. There are unquestionably folks with less than 50 MEL who made it, but they were sharp to begin with, and really took the training seriously. The company's more than 40 years of experience at hiring pilots suggests that folks with more than 50 MEL are more likely to succeed, give the company an opportunity to recover the money spent on training and wind up with a good employee and a competent pilot.