National Center for Policy Analysis:

Last year there was an unprecedented wave of new school choice programs launched across the country. Following 20 years of heated debate, new programs reflect a growing sophistication regarding the design and implementation of school choice policies. In a report for Education Week, scholars and analysts who support school choice examine the track record so far of these programs. They find it is promising and provides support for continuing expansion of school choice policies.

• Among voucher programs, random-assignment studies generally find modest improvements in reading or math scores, or both.
• Achievement gains are typically small in each year, but cumulative over time.
• Graduation rates have been studied less often, but the available evidence indicates a substantial positive impact.
• Some high-quality studies show that charters have positive effects on academic outcomes; in other contexts, the findings are more mixed.
• In general, charters seem most likely to have positive effects on student achievement at the elementary level, in math, if the school is part of a well-established charter network, if the student has been enrolled for a while, if the student is disadvantaged, and if the school is in an urban area.