1. Introduction
The papers in this special issue focus both on conceptual and measurement issues in seeking to describe young children's social and emotional development. Key conceptual issues include the need to more clearly identify the borders of social and emotional development, those that separate it from other key domains (such as cognitive development), and to more clearly delineate and distinguish the subdomains of social and emotional development (such as emotional competence) and the specific constructs within these. Conceptual issues also include the need to more fully acknowledge that measures of social and emotional development reflect not only children's behaviors, skills and knowledge, but also features of the contexts in which children grow, learn, and play. Key methodological issues include the large and widely varying number of measures of social and emotional development identified by careful review, and the relatively small number with appropriate psychometric properties needed for administration in different types of studies. A dearth of measures that have not simply been translated but that have been standardized so as to be appropriate for important demographic subgroups has also been underscored as a central issue by the special issue papers.
While identifying serious conceptual as well as methodological issues, the papers in this special issue also point to promising new developments in the measurement of young children's social and emotional development. For example, the special issue papers point to the emergence of direct assessments in this domain, helping to address longstanding issues related to heavy reliance on parent and teacher report measures. They also note critical work towards developing measures appropriate for infancy and toddlerhood, a developmental period that until recently has had an important but limited set of measures.
The purpose of this concluding paper is to highlight and provide further discussion of what we see as some of the most important issues that have emerged across the papers of the special issue, and to identify the next steps that appear most important and potentially fruitful. While we have separate sections in this concluding paper focusing on conceptual and measurement issues, it quickly becomes clear that the two are intertwined, with the lack of conceptual and definitional clarity hindering our understanding of the target and utility of specific measures. Although we begin by focusing separately on the key conceptual and measurement issues that the special issue papers highlight, it is virtually inevitable that we must conclude with a discussion of how these intersect. Indeed, our overarching conclusion is that the greatest progress will be made when measures of young children's social and emotional development are clearly mapped onto an agreed upon conceptual framework that both distinguishes social and emotional development from other broad domains, and that includes carefully delineated and defined subdomains, constructs, and corresponding behaviors