Teachers’ union president Randi Weingarten writes in the Wall Street Journal today that markets are not the answer in education. She seems to have reached this conclusion based on the testimony of a few foreign teachers’ union leaders and government officials who… run official government education monopolies.

Call me old fashioned, but I prefer to reach policy conclusions based on empirical research. So after comparing the performance of alternative school systems over the past 2,000 years, I surveyed the modern econometric literature on the subject for the Journal of School Choice. What I found is that the freest, most market-like education systems consistently outperform the sorts of state monopolies preferred by Ms. Weingarten and her fellow travelers. Appended below is the chart counting up how many studies favored education markets over state school monopolies, and vice-versa, in each of six outcome areas.

If Ms. Weingarten is aware of a similar weight of scientific evidence favoring her position, she should present it. Otherwise, why would anyone bother to heed her? More puzzling still, what was it about her alleged-dog-allegedly-bites-man op-ed that the WSJ thought worth publishing?