Friendship fosters well-being, exclusion may hurt girls’ mathematics: a two-wave cross-lagged panel model of peer relations, affect, and achievement

Abstract This study investigates longitudinal associations between peer relations, affective well-being, and academic achievement during early adolescence. Data were drawn from a two-wave study of a large nationally stratified sample of Czech students transitioning from Grade 6 to Grade 7 (N = 2,609, ages 12–13). Cross-lagged panel models were used to examine reciprocal links between friendship, social exclusion, positive and negative affect, and achievement in mathematics and Czech language, assessed using item-response-theory-scaled tests. Friendship predicted increases in subsequent positive affect, whereas social exclusion predicted declines in positive affect. Exclusion was also associated with lower later achievement in Czech language across students and with reduced mathematics achievement specifically among girls, indicating domain- and gender-differentiated academic vulnerability. Affective well-being did generally predict achievement. These findings highlight the developmental importance of peer relations for emotional adjustment and suggest that experiences of exclusion may carry direct academic consequences, particularly for girls in mathematics.