Two studies from the Community College Research Center at Teachers College, Columbia University, find many students are misplaced in remedial classes and suggest high school grades would be better predictors of college success.
One paper, by center researchers Clive Belfield and Peter Crosta, examines student-level data from a state community college system and finds that placement tests do not yield strong predictions of how students will perform in college. The authors figure that colleges could halve the rate at which students are erroneously placed in developmental courses by basing those decisions on high school grades instead of placement exams.
In the second paper, center researcher Judith Scott-Clayton studies a large, urban community college system and concludes that placement exams are better at predicting success in math than in English, and more predictive of who is likely to do well in college than of who is likely to fail.