Despite the growing recognition of the role of executive function (EF) in the development of self-regulation as well as the widely replicated neurobiological basis for this role, there is currently no highly portable, easily administered, uniform measurement battery that can reliably and validly measure individual differences in EF in children 3-5 years of age. The goals of this project were to: (1) develop a reliable and valid executive function (EF) battery for use with young children in the context of large-scale studies; (2) establish the psychometric properties of this battery; and (3) provide normative data on the battery in the context of an epidemiologically derived, racially and economically diverse sample of 600 children.