Key Questions

1. To what extent did the sorting that resulted from the policy affect algebra test scores and pass rates among students with below-norm and above-norm skills? To what extent were failure rates affected by the overall skill level in the classroom versus students’ own abilities relative to their classroom peers (i.e., ‘‘fish pond effects’’)?

2a. For above-norm students post-policy, how did the outcomes differ between students who took algebra in mixed-skill classrooms with below-norm students receiving supports and those in homogenous classes without such below-norm students?

2b. Similarly, for below-norm students, how did the outcomes differ between those who took double-dose algebra in mixed-skill classrooms and homogenous classes with all below-norm students?

3a. In what ways did the policy, and the ability sorting induced by the policy, affect students’ classroom climate and instructional experiences for below-norm and above-norm students?

3b. How were these changes in classroom environment related to students’ test scores and pass rates?


In 2003, Chicago schools required students entering ninth grade with below-average math scores to take two periods of algebra. This led to higher test scores for students with both above- and below-average skills, yet failure rates increased for above-average students. We examine the mechanisms behind these surprising results. Sorting by incoming skills benefited the test scores of high-skill students partially through higher demands and fewer disruptive peers. But more students failed because their skills were low relative to classroom peers. For below-average students, improvements in pedagogy and more time for learning offset problems associated with low-skill classrooms. In some cases, classrooms were not sorted, but below-average students took an extra support class simultaneously. Test scores also improved in such classes.

The final, definitive version of this paper has been published in American Educational Research Journal, 50(4), August 2013 by SAGE Publications Ltd./SAGE Publications, Inc., All rights reserved. © 2013