The findings suggest that delinquent behavior is not a direct response to academic failure (poor grades). Rather, the primary factor in determining delinquent behavior was the ability of a youth to control his/her behavior inside and outside the classroom. Those with low self-control found it difficult to achieve good grades and regulate their impulses. Students with good grades may also be less delinquent because of their strong bonds to persons who engage in conventional behavior. Thus, self-control and positive social bonds, rather than academic performance, were the factors more directly related to delinquent behavior. The study was conducted in the spring of 1988 and involved 24,599 eighth-grade students, who were randomly selected from more than 1,000 private and public schools across the United States. The sample was surveyed again in the 10th (1990) and 12th grades (1992), including those who had dropped out of high school. Follow-up surveys were conducted 2 (1994) and 8 years (2000) after the scheduled date of high school graduation. Analyses for this study relied only on the first three waves of data collection. Complete data were obtained on 14,282 youth. Measures were official grades and test scores, self-reported bonds to school and parents, teacher-reported effort, demographic variables, and self-reported delinquency. Self-control was measured by using teacher ratings of student effort in school. Effort in school was assumed to reflect a youth's ability to defer gratification and display diligence, tenacity, and persistence. 3 tables and 50 references