importance, such as school achievement, life satisfaction, or avoidance of the criminal justice system.

1. Evidence that the domain is a frequent target of investment or intervention and that child performance in it is affected by changed environmental conditions.

None of these by itself settles the matter, and it is not always the case that all three are available, but convergence among them suggests that a domain deserves attention in this report.

In categorizing the domains, for the sake of simplicity we adapt the distinctions adopted by the National Education Goals Panel (Kagan, Moore, and Bredekamp, 1995), since these map onto both the developmental research literature (McCartney and Phillips, 2006; National Research Council and Institute of Medicine, 2000) and state and federal standards and policies. The boundaries between the domains discussed are, we acknowledge, artificial, as is the way constructs are categorized within them. Vocabulary, for example, is categorized here under Language and Literacy, but is also often included in Cognition as it is so directly relevant to performing well in mathematics, science, and other domains of general knowledge. Similarly, some researchers include constructs identified in this report as part of Approaches to Learning in the category of Socioemotional Functioning. Thus, we offer this categorization as a heuristic for discussing constructs and their measurement, not as a grand theory of child development. We differentiate and discuss five domains in the following chapters:

1. physical well-being and motor development,

2. socioemotional development,

3. approaches to learning,

4. language (and emergent literacy), and

5. cognitive skills, including mathematics.

This categorization provides an initial mapping of what might be considered important enough aspects of children’s development to deserve systematic scrutiny from pediatricians, early childhood educators, parents, researchers, and policy makers. Some of these domains are better conceptualized and better instrumented than