Massachusetts’ John and Abigail Adams Scholarship program was launched in 2004 by then Gov. Mitt Romney offers free tuition to the top 25 percent of high school students based on their 10th-grade Massachusetts Comprehensive Assessment System (MCAS) scores to attend in-state public universities.

A new Harvard University study finds that the program has worked in terms of keeping college students in state, but it has contributed to keeping kids in schools much longer than expected. As HechingerEd reports that the Harvard researchers found:

… that, while the program has accomplished its goal of keeping more of these students enrolled in Massachusetts, the students’ probability of graduating on time was 40 percent lower than if they’d attended higher-quality private institutions.

“Our working hypothesis is that these kids are giving up opportunities to go to campuses that are more competitive and much better resourced than the public system is,” said Joshua Goodman, an assistant professor of public policy at the Kennedy School and coauthor of the study.

The result, he said, is that the students vie for limited faculty time and often can’t get into courses they need to graduate within four years of enrolling. The report concludes that students have a poor understanding of the comparative quality of colleges and universities, and that public institutions need to be improved in other ways than by simply trying to elevate the quality of students.

Politicians interested in keeping home-grown talent should design scholarship programs that include all higher education options and not cave to political pressure to favor one sector over another. Diverse student populations and future workforces require equally diverse educational choices—and public institutions require a good healthy dose of competition for students and their education funding to perform at their best.