>For one, the absolute leading researchers are at the top universities, and there is a big gap between these people and merely very good researchers. I have no

>For one, the absolute leading researchers are at the top universities, and there is a big gap between these people and merely very good researchers. I have noticed the opposite effect. Typically the best researchers are the worst instructors, prepare the least for their courses and couldn't care less about their teaching quality. Those that are both solid instructors and researchers are exceptionally rare. While leading researchers may have a better grasp of their specialized field this is often not applicable in graduate courses. The exception being when those professors develop an entire course around their research and (often) force many of their research students into that course.