Joel Greenblatt is an esteemed professor at Columbia University (the only place I would consider doing a masters in anything finance related). He also is a very successful portfolio manager (the very rare breed of professors -- those with practical experience who care more about the real world than the theoretical).
For a top professor, you might expect he uses very complicated models or high level mathematics... well he doesn't:
"I look for obvious things when looking for bargains, not something terribly obscure ... wouldn’t involve higher mathematics or special sleuthing talents."
"When doing in depth analysis of companies, I care very much about long term earnings power, not necessarily so much about the volatility of that earnings power but about my certainty of “normal” earnings power over time. My goal is to buy a company at a low multiple to normal earnings power several years out and that the company earns good returns on capital at that level of normal earnings ... I usually just look at a simple multiple to normalized earnings. If I can buy something at a very low multiple and I have confidence in the earnings stream, I don’t have to calculate a DCF to know whether I want to buy it."
As you may have noticed in the video I posted on him in an earlier post, he uses a simple approach that works.