Research on the use of sociometric ratings (peer nominations) in predicting achievement and school outcomes is briefly reviewed along with developments in instrumentation. Particular attention is given to a newly revised system of collecting teacher and self ratings along with peer nominations in a comprehensive assessment of the affective and social functioning of elementary-school children. An empirical study of the potential effects of class size on the distributions of sociometric choices is presented and peer nominations are found to be robust to classroom size effects. This study suggests that peer nominations continue to be a robust and important predictor of potential learning difficulties in classrooms, when used judiciously in combination with other sources of data. (Author)