Quote from gwb-trading:
Actually, this figure has been found to be total B.S. The distribution of teachers' ranking in their class is a bell curve that pretty much mirrors all other subjects. 1/2 of teachers in the U.S. DO NOT come from bottom 1/3 of their class from a GPA perspective. One half of the teachers in a large urban city where this study was done and promoted by McKinsey were in the bottom 1/3 of their class - the reason - no decent teacher wants to teach in a tough urban Title 1 school.
People can argue if the education required to become a teacher is as difficult as a degree in engineering or medicine. In my opinion it is not. This is why engineers are paid more than teachers - ignoring the fact that teachers only work 10 months per year.