Figure 1 shows the developmental stages and time periods during which the Add Health cohort was followed from early adolescence into adulthood, and the types of environmental data (top panel) and biological data (bottom panel) that are available across the waves of data collection. The strength of Add Health, and thus the strength of the Add Health sibling pairs data, is the multiple levels of data that allow researchers to examine social, behavioral, environmental, biological, and genetic linkages in health and behavior across the life course from early adolescence into young adulthood.
