Tillman, K. H. (2008). Co-resident sibling composition and the academic ability, expectations, and performance of youth. Sociological Perspectives.
vol. 51 (4) pp. 679-711
This study examines the effects of living with "nontraditional" siblings (i.e., step- and/or half-siblings) on the verbal ability scores, grade point averages (GPAs), and college expectations of adolescents and whether sibling composition effects are moderated by family structure. On average, youth who live with step- or half-siblings report significantly poorer outcomes than youth who do not. The sibling composition effects on verbal ability scores and grades are similar in direction and magnitude across family types. The association between nontraditional siblings and the college expectations of youth, however, appear to be conditioned by family structure, such that youth living with two biological parents or single mothers are negatively affected by the presence of half-siblings and the expectations of youth living in stepfather families are negatively affected by the presence of step-siblings. The mechanisms underlying sibling composition effects on academic-related outcomes also vary by family structure.
Tillman, K. H.