It's long been known that high-poverty, high-minority schools have higher rates of teacher turnover than other schools. But is turnover in such schools always a bad thing? In a new paper out from the National Bureau of Economic Research, economists Eric Hanushek and Steven Rivkin take on the issue and provide some fresh food for thought.
The researchers looked at data from an urban district in Texas from 1995-96 and from 2000-2001 in grades 4 and 8, using a matched teacher-student data set. The district has a whopping 30 percent annual "exit rate" among new teachers and 18 percent among veterans.
The researchers found that, of the "exiting" teachers, those leaving Texas schools entirely and those that sought out another school in the district were on average less effective relative to teachers who stayed in their schools in raising mathematics scores.
But when they sliced and diced the data, they found a much more complex set of factors. When the data were correlated by school type, for instance, the researchers found that the teachers who left low-achieving schools and schools with a higher concentration of black students were less effective, compared with "stayers," than teachers who left higher-achieving schools or those with fewer black students.
The one exception seems to be for novices with but a year of experience under their belts. First-year teachers who change schools or districts were significantly more effective than those who stayed, while veterans who made such switches were significantly less effective.
The findings reverse common narratives about teacher turnover: It appears that high-needs schools aren't systematically losing their best teachers. The authors add, however, that the benefits of losing weak teachers in these schools are offset by the fact that such schools often restaff with new teachers, who generally don't become maximally effective until they've been in the classroom about three years or so.
The paper doesn't take into account the disruption and low morale that seem likely to accompany an always-revolving staff door. Nor could the researchers separate out which teachers left of their own volition and which ones were encouraged or forced to leave by principals.
The bottom line of the study: Turnover in challenged schools isn't always as debilitating as it's made out to be. But the fact that weak teachers tend to leave is hardly a substitute for a human-capital strategy designed to attract teachers, help them become highly effective, and keep them in the schools where they're needed.