Good data on teacher attrition broken out by the type of school that teachers are leaving can be awfully hard to come by. Accordingly, groups that supply teachers to high-poverty districts, like The New Teacher Project and Teach For America, can have a hard time defending their seemingly high attrition rates to their critics. The national average for high poverty schools is cited as anywhere from 15 to 20 percent, but even this figure disguises the attrition differences between 'really, really high' poverty schools from the 'not-quite-as-high' poverty schools.

The Illinois chapter of ACORN, a community organization serving low- and moderate-income families, has come out with a report that provides useful quantitative evidence of just how bad retention rates can be in the highest poor and minority schools. In 64 schools in Chicago, this report found a teacher turnover rate of 25 percent--well above the national average--but also a staggering 39 percent turnover rate for these schools’ first-year teachers.

While there's nothing surprising in this short report, it's useful to have around as one of the few analyses that quantifies the speed at which the doors of the neediest inner-city schools revolve.