The academies have literally been designed to ensure a decent amount of people fail, after several years of high% success rates. The grading is hard on purpose. There are also many subjective factors at play, judgement calls, benefits of the doubt etc. If you are an attractive person of a certain gender, you have a far less chance of failing. That is just basic world facts though. The people who constantly study and stress and complain that their classmates don't take shit serious enough, aren't necessarily the most successful either.... because at a certain point you either have the aptitude to see a conflict and properly resolve it or not. There are a myriad of reasons but if you are smart, motivated, and don't make everyone there hate you... you have a good chance to make it. Many legacy controllers who got their academy seat through daddy nepotism have failed (much to the shock an awe of their "I pulled strings w the agency im a big shot" parent).... which is one way you know theyre doing something right!