Researchers at Indiana University reviewed state test scores and found that students who transferred from public schools to charter schools lost ground academically for the first few years. Eventually, if they remained in the charter school, they caught up to their public school peers, but nearly half transferred back to their public school. It may be, as in the case of voucher studies in I Diana, that the weakest students were likeliest to leave the charters.

”Researchers from the Indiana University School of Education-Indianapolis examined four years of English and math ISTEP scores for 1,609 Indiana elementary and middle school students who were in a traditional public school in 2011 and transferred to a charter school in 2012. The main findings were that students who transferred had lower math and English score gains during the first year or two in their new school than if they had stayed in a district school.

“The researchers were able to draw the conclusion by using a type of statistical analysis that enabled them to compare students’ actual score gains at the charter school to potential gains had they not transferred from a traditional school.

“But for the students who stayed in charter schools for three years or more, some of those gaps disappeared, and students caught up with where they would have been if they hadn’t transferred. Both of these results — the dip in score gains after transferring and the increase over time — are consistent with other studies, researchers said.

“Overall, these results indicate that the promise of charter schools as a vehicle for school improvement should be viewed with some skepticism,” said study co-author Gary R. Pike, a professor of education at Indiana University–Purdue University Indianapolis. “Our results suggest that charter school experience for most students does not measure up to expectations, at least for the first two years of enrollment.”

“The researchers also found that of the original number of students who transferred to a charter school in 2012, 47 percent returned to a traditional public school by 2016. Only about a third of students remained enrolled in charter schools long enough to see their scores catch back up. The study called the mobility “problematic,” and suggested other researchers look into it further.”

The study contradicts an earlier CREDO study of Indiana charters.

However, the researchers cautioned not to draw national generalizations from the study of one state.