My studies of the 500 largest American corporations show a highly statistically significant link between those that make a formal public ethical commitment to their stakeholders and multiple measures of corporate performance.

ECONOMIST: Letters

The foundation and others have estimated that it could cost between 1.5% and 2% of the overall budget for teacher compensation and benefits to implement a feedback and evaluation system based on multiple measures of teaching performance.

CNN: Bill Gates: Invest in better teaching

The project also found that using multiple measures to understand a teacher's performance -- including classroom observations, student surveys and growth in student achievement -- provides a richer and more reliable picture of a teacher's strengths and areas for improvement than any one measure alone.

CNN: Bill Gates: Invest in better teaching