This study examines developmental change across adolescence in the similarity of friends versus nonfriends. This differential in similarity is a key aspect of the organization of the peer context of development: The stronger the correlation between friends for an attribute, the more the attribute delineates clustering and divisions of friendships.…

This article addresses the relationship between academic achievement and the student characteristics of absence and mobility. Mobility is a measure of how often a student changes schools. Absence is how often a student misses class. Standardized test scores are used as proxies for academic achievement. A model for the full joint distribution of…