Leadership roles at West Point are chosen by a board of officers (not cadets). Cadets are evaluated the entire four years there, so there is plenty of material to review. It is not just class rank or academic performance, but also leadership and physical fitness that is included in the evaluation. As the cadets progress through the four years, certain cadets tend to rise to the top and are identified as potential leaders. They are then given leadership positions typically given to cadets in each class. For instance, 3rd class are team leaders, 2nd class fulfill NCO positions, and 1st class fill officer positions. The evaluations they receive in lower level leadership positions help determine what positions they will be assigned as they move through the four years. The good news in the end is that all that graduate will be lieutenants in the active army.