Drawing input from 3, 000 classroom teachers, the project highlighted several measures that schools should use to assess teacher performance, including test data, student surveys and assessments by trained evaluators.

WSJ: Bill Gates on the Importance of Measurement

Thirty three states have laws to measure teacher performance though most rely on test based systems in large part because they are cheaper.

FORBES: Bill Gates Says There Is Something Perverse In College Ratings

It's clear that systems that gauge student, teacher and school performance on standardized test scores put intense pressure on those results and inevitably tempt people to finagle them.

CNN: STORY HIGHLIGHTS