I know this is more than one question. I'm hoping you can address these all at once?

How are the ways in which organizations choose to measure and evaluate the performance of their segments tied to how managers of those segments get evaluated? What are the ways those approaches can fairly evaluate managers? How can those approaches sometimes unfairly evaluate managers? Can people "game" this system? If so, how? What can be done to ensure both accurate segment performance evaluation and fair manager evaluation?