School, parental and peer group effects have been identified as being influential in shaping the decision of students to participate in post-compulsory education, but the analysis of each effect separately is rare. Using a random effects logistic regression approach, estimates of the importance of school, parental and peer group effects on student choices are presented which suggest that peer groups play an important role in determining boys' choices at 16, while the decision to stay on across gender is strongly influenced by parental background. Profiles show that the social class of peers' fathers influence strongly the probability of a student staying on. (Contains 2 figures, 5 tables, and 11 notes.)