Key difficulties in identifying the effects of ability grouping on student achievement

The paper presents empirical evidence that earlier research may have overstated the impact of ability grouping and tracking on inequality in student achievement. We list six key difficulties facing research on the effects of grouping on student achievement. Each of these difficulties offers opportunities for further research and for collection of more appropriate data sets. Strong conclusions as to the differential effect of ability grouping on high-achieving and low-achieving students ale probably not yet warranted. [JEL 121] (C) 1999 Elsevier Science Ltd. All rights reserved.