That report on DC vouchers

As Ed Week reports , a new (and unusually scientific) study of the District of Columbia's voucher program does show some significant positive impacts. Looking at the actual report, the positive impacts were for:

• Participants who applied from schools not classified as “ in need of improvement.”
• Students who applied with "relatively higher levels of academic performance."
• Female students.
• Students entering grades K-8.
• Students from the first cohort of applicants.

Similar impacts were not found for:

• Students who entered "with relative academic disadvantage."
• Students who applied from schools in need of improvement or were in the lower in the lower third of the test score distribution among applicants.
• Male students.
• Students entering high school.
• Students in application cohort 2.