There is no shortage of research on the importance of good teaching. For decades, study after study has shown that there are large differences in effectiveness from one teacher to another and that these differences can have a lifelong impact on students. A recent study that tracked 2.5 million students over 20 years determined that those with…

Discussions of teacher turnover usually focus on "how many" teachers leave schools each year, without regard for their performance in the classroom. This oversimplification masks the real teacher retention crisis: not only a failure to retain enough teachers, but a failure to retain the "right" teachers. This executive summary presents findings of…

"Irreplaceables" are teachers who are so successful they are nearly impossible to replace, but who too often vanish from schools as the result of neglect and inattention. To identify and better understand the experience of these teachers, the authors started by studying 90,000 teachers across four large, geographically diverse urban school…

Successful teachers make successful schools. Yet some schools are better than others at accelerating student learning by developing and keeping great teachers, even compared to schools that serve the same population of students and have access to the same resources. These schools are called "greenhouse schools"--schools with carefully fostered…