EdWeek shares the weights given to value-added results in D.C.'s approach, and I've graphed them above.
That's two different evaluation programs, one for teachers whose students are tested in their subject, and another for teachers whose students are not tested that way. For one group, scores loom large, while for the other they play a tiny role. That's a disturbing difference, capable of dividing a school and providing perverse incentives for teachers to seek out transfers into untested subjects.
The Race to the Top criteria call for all states to ensure that "student growth" becomes "a significant factor" in teacher evaluations. Last week, the Kentucky Board of Education indicated starting support for Commissioner Holliday's desire to do something similar here. The graph above is, to my eyes, the best demonstration I've yet seen of just how challenging that effort is going to be.