& Walder, 1984) and from ages 8–42 with 4 measurement occasions (Kokko, Pulkkinen, Huesmann, Dubow, & Boxer, 2009). Studies have also examined trajectories of delinquency from ages 7–19 with 13 measurement occasions (Keijsers, Loeber, Branje, & Meeus, 2012) and from ages 8–46 with 9 measurement occasions (Farrington, 2003). In general, previous studies have shown that, on average, externalizing problems decrease from early to middle childhood (Keiley, Bates, Dodge, & Pettit, 2000; Leve, Kim, & Pears, 2005), increase during adolescence (Sampson & Laub, 2003), and decrease from adolescence to adulthood (Sampson & Laub, 2003). We seek to extend prior studies by examining externalizing problems of children from the United States annually from ages 5–27 (except ages 18, 25, and 26) with 20 measurement occasions, and to evaluate multiple risk factors as predictors of these trajectories. Similar to Odgers et al. (2008), we obtained measures from different, although developmentally-appropriate, sources at different ages.
