There is a forced rating system - you are either a 1 (excellent), 2 (good), 3 (not good). But then within the 2 ratings you're either a 2+ (almost a 1), 2 (good), 2- (not as great as a 2+, not quite as good as a regular ole'2 but also not as bad as a 3... you're just OK). All of the ratings are completely subjective and often times turn into who they think will be the best person to promote in the long run and not as much about the work you actually do. The jobs are so different it's extremely difficult if not impossible to rate one person against another - even at the same level in the same department. You aren't selling something or making something, so there is no objective performance possible.
Over the last 24 years I've seen this ratings process as a manager as well as an employee and I can say it's extremely demoralizing and a system that divides and de-motivates employees more than anything else. A single person based on their subjective impression of you can rate you poorly and you have no recourse. That rating impacts potential for promotion, salary today and over the next 2 years, profit sharing, and your image with future managers once you move on to another role.