According to a study published in Policy Studies Journal, religious private schools in Milwaukee’s school voucher program are outperforming secular private schools. The success of religious private schools has a lot to do with their affiliations with larger institutions.

“We find that 41 percent of all private voucher schools operating in Milwaukee between 1991 and 2015 failed,” the study’s authors write. “Start-up voucher schools, and those unaffiliated with a larger institution, have comparatively higher failure risk over time.”