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…

"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…

Experience makes a difference--especially at the beginning of a teacher's career. On average, teachers with some experience are more effective than brand new teachers. Teachers improve the most early in their careers. One study found that "close to half of the teacher achievement returns to experience arise during the first few years of teaching."…

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…

A vast gulf in academic achievement separates public schools in Washington, D.C.'s poorest neighborhoods from those in its most affluent. Achievement Prep, which serves 4th-8th graders in D.C.'s impoverished 8th Ward, is an outlier. Yet in 2011, 60% of Achievement Prep's "scholars" scored proficient or advanced in reading on the DC-CAS tests,…

This paper presents myths as well as facts about value-added analysis. These myths include: (1) "Value-added isn't fair to teachers who work in high-need schools, where students tend to lag far behind academically"; (2) "Value-added scores are too volatile from year-to-year to be trusted"; (3) "There's no research behind value-added"; (4) "Using…