Content Summary : This paper addresses five dimensions relating to the assessment of social-emotional development in children: (1) Social Competence; (2) Attachment; (3) Emotional Competence; (4) Self-perceived Competence; and (5) Temperament/Personality. Social Competence. The first dimension is social competence, which we define theoretically as effectiveness in developmentally appropriate social interactions (Rose-Krasnor, 1997). Such effectiveness should be assessed using a multi-informant, multi-method perspective––i.e., who considers the social interaction effective? Informants should include parents, teachers (preschool/childcare, elementary, high school), agemates (i.e., peers), and children themselves, as well as independent observers. Each of these informants has a unique viewpoint that can enrich our understanding of the child’s social competence strengths and weaknesses. Next, for each informant, a number of more specific skills crucial to social effectiveness need to be measured. What is measured differs across developmental epochs, as detailed later in this white paper. In general, however, these specific skills would include elements like cooperation, helpfulness, ability to resolve conflicts, etc. (see Compendium of Measures, p. 1). Thus, measures that tap effectiveness in social interaction are recommended, as this construct may be differently perceived at different ages depending on each age’s developmental task. Multiple informants are extremely desirable, as is sufficient breadth of coverage, at each age level, for the various skills that instantiate such effectiveness.