Fig. 1.

Collection and linking of residential address information in the ABCD Study. Current residential data include both retrospectively collected primary residential addresses as well as prospective data collection at each annual study visit. Exposure assessment comes from linking geocodes to external data resources. Linkage has primarily focused on addresses collected at baseline. In future releases, retrospective and prospective data will be linked with special consideration to the spatial and temporal domains to minimize misclassification between when and where a child resided and the contextual variables of any given environmental dataset. API = application programming interface. QC = quality control. PII = personally identifiable information.