This document describes the construction of polygenic scores (PGSs) associated with various phenotypes for respondents participating in the National Longitudinal Study of Adolescent to Adult Health (Add Health) by the Social Science Genetic Association Consortium (SSGAC). Research has shown that many outcomes of interest in the health, behavioral, and social sciences are influenced by genetics (Domingue et al. 20161; Plomin et al. 20162; Turkheimer 20003). For most human traits/behaviors, commonly referred to as phenotypes, it appears that the genetic influence on the phenotype is highly polygenic; i.e., there is no single gene that can account for the association between genetic variance and variance in the outcome. Instead, the influence of genetics on most phenotypes appears to be due to many small associations across thousands, and possibly millions, of individual single-nucleotide polymorphisms (SNPs, pronounced snips) (Chabris et al. 20154). Polygenic Scores allow researchers to avoid the methodological complexities of including thousands, or millions, of covariates in their analyses by condensing, into a single measure, the associations between individual SNPs and the phenotype of interest (Plomin, Haworth, and Davis 20095).