Academic Achievement, Externalizing Problems, and Close Friends in Middle School: Testing a Developmental Cascade Model Leading to Educational Attainment in the Late Twenties.

Because educational attainment is associated with well-being in the long term, it is important to understand the developmental processes that enhance academic outcomes during adolescence. Also, although the importance of friends is well documented in adolescence, little is known about how close friends' characteristics work together with youth's own characteristics to shape adolescents' educational trajectories. This study fills an important gap in knowledge by focusing on how middle school students' academic achievement and externalizing problems are associated with their friends' achievement and externalizing problems over time, and how these variables predict educational attainment in adulthood. This study innovates by examining developmental cascades involving adolescents' academic achievement, externalizing problems, and these characteristics in their close friends in the context of random-intercept cross-lagged panel modeling (RI-CLPM), which disentangles within-person changes and between-person differences during the three years of middle school. The sample included 998 middle school students (Mage at recruitment: 12.21 years old; SD = 0.37 years), 42.3% of whom were European Americans, 29.0% African Americans, 6.8% Latinos, 5.2%, Asian Americans, 16.2% youth of other ethnicities, including mixed ethnicity, and 47.3% were female. At the within-person level, only one type of interdomain cascade was corroborated, as youth displaying high levels of externalizing problems reported close friendships with low-achieving friends in the next year. At the between-person level, only the random intercept representing the stability of adolescents' academic achievement throughout middle school predicted educational attainment in adulthood (average of 28 years old). In essence, this study clarifies that the etiological mechanisms leading up to adult educational attainment involve only adolescents' own stable academic achievement, and not their externalizing behaviors or friends' academic achievement and externalizing behaviors.