Marian Sigman and Ron Ruskin are the authors of Continuity and Change in the Social Competence of Children with Autism, Down Syndrome, and Developmental Delays, published by Wiley.

• Abstract. Background and Goals of This Study.Stability of Diagnosis and Intelligence.Nonverbal Communication, Play, and Language Skills.Social and Emotional Responsiveness.Peer Interactions in School.Correlates and Predictors of Peer Interactions in School.Summary and Discussion.References.Acknowledgments..Commentary.Methodological Issues in Cross-Syndrome Comparisons: Matching Procedures, Sensitivity (SE), and Specificity (SP) (Carolyn B. Mervis and Byron F. Robinson).Response to the Commentary by Mervis and Robinson (Marian Sigman).Contributors.