Private school choice programs have exploded in the last couple years. A string of Republican-led states have launched far-reaching initiatives that allow families to use public money to access private education.

This has drawn fierce debate and raised big questions. Do vouchers raise test scores or lower them? Do they help or hurt students over the long term? Do they damage public schools or push them to improve? What will the financial impact be?

Chalkbeat combed through the academic research to get some answers.

Two caveats before we begin. First, context matters. Private school choice programs differ from place to place and have evolved. Recently passed programs have been broad based — often they’re open to all students, including those from affluent families or those who already attend private school. Prior programs were usually limited to a subset of students — say, those in low-achieving schools or those whose families are low-income. Studies have been done on some of these older programs, but not yet on the new ones. That means that prior research may be an imperfect guide for future results.

Second, the voucher debate is often about values. The recent expansion of private choice has been driven as much or more by cultural issues than questions of school performance. But research studies can’t answer philosophical questions on whether public money should go to religious schools or if providing more choices for parents is an inherent good. They can’t speak to debates about access for LGBTQ students or what type of curriculum is taught in class.

With that in mind, here’s what we know from research:

Recent studies find little evidence that school vouchers improve test scores — in fact, they’ve sometimes led to score declines. Older studies are more positive.

In the last several years, major studies in Indiana, Louisiana, Ohio, and Washington D.C. have shown that low-income students do not see improved test scores from attending private schools. If anything, students’ scores tended to decline. Choice advocates initially suggested that results would bounce back over time, but in three of the four cases achievement was worse in math, even after multiple years.

Read the full article about private school choice programs by Matt Barnum at Chalkbeat.