School-choice advocates argue that children will get a better education if they can leave public schools for charter or private schools, especially in urban areas. The Indiana Growth Model tells a different story.
It suggests public schools, overall, are performing better than charter schools or the private schools — most of them religious schools — that are getting state vouchers.
The growth model is a statistical tool that measures students’ test-score gains compared to those of students with similar academic histories. It may not be perfect, and critics argue that it shouldn’t be over-used. But it’s unquestionably a better measure of school effectiveness than standardized test scores or school grades, which have been shown to correlate closely to student demographics.