Teacher Turnover Tracked in City District

Educators Who Move On Are Not Necessarily the Best and Brightest

A new Texas study punctures the commonly held notion that high levels of teacher turnover in poor, urban schools result from an exodus of the profession’s “best and brightest.”

The study, scheduled to be posted online this week by the Cambridge, Mass.-based National Bureau of Economic Research, a nonprofit research organization, draws on data on thousands of teachers and 4th through 8th grade students in an unidentified big-city Texas district that researchers call “Lone Star.”

Rather than measure teachers’ quality by whether they had passed certification exams or had earned advanced degrees, the researchers looked at the test-score gains students made from year to year on state mathematics tests to determine...