triumphs are significant, and the medical and public health systems should take pride in what has been accomplished. Despite these accomplishments, however, there are growing numbers of children in the United States with serious chronic diseases, including many emerging disorders that reflect the interaction of genetics, behavior, and the environment. Childhood obesity, diabetes, and asthma rates are among the highest in the world and are increasing rapidly. Intentional and unintentional injuries, mental health disorders, and attention deficit disorder are highly prevalent. Moreover, many of these conditions are not equally distributed across the population; some groups experience substantially higher rates than others. Finally, the long-term consequences of these disorders are significant, because unhealthy children often become unhealthy adults. Health during childhood must be a major concern both because children are important in their own right and because the nation cannot thrive if it has large numbers of unhealthy adults.

In response to a congressional request, the Board on Children, Youth, and Families of the National Research Council and the Institute of Medicine formed the Committee on Evaluation of Children’s Health: Measures of Risk, Protective, and Promotional Factors for Assessing Child Health in the Community. The committee was directed to review definitions of children’s health, factors that influence it, the data and methods used to monitor children’s health and the factors that affect it, and how data can be used to inform policy and practice. The committee used the term “children” to refer to the period between birth and 18 years and focused on population-level issues. Although data to monitor population health are often collected at the level of the individual, the committee’s focus is on the health of local, state, and national populations of children.

In beginning our work and reviewing the available literature, the committee agreed on six guiding principles:

• children are vital assets of society;

• critical differences between children and adults warrant special attention to children’s health;

• children’s health has effects that reach far into adulthood;

• the manifestations of health vary for different communities and different cultures; and

• data on children’s health and its influences are needed to maximize the health of children and the health of the adults they will become.

Over the past century, the United States has instituted important health monitoring and surveillance activities. It also has adopted important research