In 2005, the Chicago Teachers' Union's president, Marilyn Stewart, was uniformly negative in her assessment of Renaissance 2010, stating that "Chicago's charter schools had scores that were in the basement.
[...] All Chicago-based charter schools had scores below the statewide average in third-grade reading, third-grade math, fifth-grade reading and eighth-grade math".
[1] A 2009 study by University of Chicago researcher Diane Whitmore Schanzenbach found more mixed results, that "test scores in the Renaissance schools slightly lagged those of students with similar backgrounds who attended neighborhood schools — though not to a statistically significant degree.
But results were far from homogeneous, with some Renaissance schools posting decidedly stronger test scores compared to others."
Demonstrating the divisive nature of the Renaissance 2010 plan, proponents have used this study to argue that the new schools are solid foundations for better education, while opponents have used this same study to claim that the new schools provide little to no gain for their cost and social disruption.