Teacher hiring is essentially random

Interesting Slate piece quotes evidence to suggest that schools are no better than random at hiring good classroom teachers.

For instance, in 1997, Los Angeles tripled its hiring of elementary-school teachers following a state-mandated reduction in class size. If L.A. schools had been doing a good job of picking the best teachers among their applicants, then the average quality of new recruits should have gone down when they expanded their ranks—they were hiring from the same pool of applicants, but accepting candidates who would have been rejected in prior years. But as researchers Thomas Kane and Douglas Staiger found, the crop of new teachers didn’t perform any worse than the teachers the school had hired in more selective years.

(There’s more in the article.) Of course, we can’t tell whether this is because it’s hard to identify good teachers, or that the system somehow doesn’t care.