Lance Hill points out that his state has a double standard when it evaluates teachers by test scores. Some who teach high-scoring students were rated “ineffective” because their students showed no growth. Their ratings were set aside for review. They were treated differently from those who teach high-needs students.
The Louisiana formula:
Excuses for the teachers of the high-performing. No excuses for those who take on the biggest challenges.
Diane Ravitch's blog 
Now who would I want to teach if I were an excellent teacher in LA who had the option of choosing high-performing or high-needs students?
Hmm. Now THERE’S a stumper!
The students who need top teachers the most are going to be the least likely to get them under this type of practice. Those in control never consider the effects of their actions on the people most affected by them….first students then teachers. Thanks, Lance Hill for putting this out for all to see.