Objective. We compared abilities and strategy use of at-risk youth aged 16-21 yr with those of a community sample of high school students using a performance measure of executive function, the Weekly Calendar Planning Activity (WCPA). METHOD. We recruited students from an alternative school for at-risk youth (n 5 113) and from community high schools in the same region (n 5 49). We collected demographic information from and administered the WCPA to both groups. Results. The at-risk group made more errors, used fewer strategies, and broke more rules than the community group; however, the groups were similar in average time for planning and task completion. Moderate relationships were found between WCPA and academic performance in the at-risk group. Conclusion. Comparison of at-risk and community youth provides support for discriminant validity of the WCPA and indicates that the WCPA is useful in identifying adolescents who are at risk for occupational performance deficits.