Student ratings of instruction certainly are unreliable at judging quality instruction. Sure, they can provide indications of good or bad performance but they cannot be the measure. In my department, we count a combination of student reviews, formal peer review, advising students, and teaching workshops / conferences attended as to measure effective teaching.
What does your department / university do to measure quality teaching for the purpose of tenure / promotion? How well do you feel the system works?
Thank you in advance!