Many institutions of higher education have designed a variety of first-year seminars to facilitate student transition to college. These seminars are often assessed in terms of their overall impact on academic performance and retention. However, limited research has been conducted to identify the types of seminars that are most effective for specific kinds of students. This article describes a study that used cluster analysis to develop a typology of student groups based on precollege characteristics and examined the influence of two types of seminars on the academic performance and retention of each student group. The findings indicate that the influence of each type of seminar varied among the groups. They also suggest that students' precollege characteristics can be moderated by participation in the appropriate type of first-year seminar. Knowledge of their own students' characteristics may assist institutions in targeting students more effectively for particular first-year seminars and, thus, enhance academic success and retention. (Contains 8 tables and 3 notes.)