Although a growing literature has documented the effectiveness of informal group work during class sessions, virtually no data exist on which students are collaborating. As a result, instructors rarely know whether students are self-sorting in ways that maximize learning. This article explores which undergraduate students worked together on each…

This paper addresses the problem of heterogeneity of samples of learning disabled (LD) children by comparing five different systems for identifying homogeneous subgroups in terms of their ability to predict longitudinal reading and mathematics scores. One hundred and sixty LD children served as subjects. Three of the five subgrouping systems were…