Joshua Cowen takes a closer look at schools in Milwaukee:

Using data from the Wisconsin state education agency’s website, I calculated that the 10 schools reported by Slate to be teaching or affiliated with creationism reported dramatically lower percentages of students proficient in science compared to other private schools participating in the voucher program. Over the 2010-11, 2011-12, and 2012-13 school years, nearly 70 percent of students in grades 4, 8, or 10 scored below “proficient” levels in science, compared to “only” 54 percent of students in other voucher schools (the difference is statistically significant). Setting aside the question of whether the other voucher schools are performing adequately on the state’s science exam, the point is that creationist schools are doing especially poorly. Lest we worry that this comparison is by definition unfair because the state’s science exam may be precisely what the creationist schools are teaching against, consider that the results are similar in math, reading, language arts, and social studies. In each subject area, the creationist schools had far fewer proficient students than the other voucher schools.