This study compares traditional lecture (TL) and personalized system of instruction (PSI) teaching methods for an introductory criminal evidence class at Cerritos College (California) during the 1974-75 academic year. The subjects were 189 lower division students, the vast majority of whom were declared law enforcement majors. Since both sections each semester were day offerings, most students were full-time and not currently employed in law enforcement agencies. Registration counts indicate that significantly more students were attracted to TL than to PSI sections, reflecting students' reluctance to attempt experimental curricula. Although significantly higher percentages of PSI students achieved A and B grades, the withdrawal rate was significantly higher in the PSI sections, and may correspond to the lower grades earned in the TL sections. PSI students were, however, able to complete course requirements sooner than TL students. Because the course has open enrollment and lacks the proper randomization, this study's internal validity is suspect. Even with proper control groups, the PSI group's performance relative to the TL group's must be questioned because PSI offers the advantage of clear goals and objectives in the study guide. A review of the literature is included, and the author recommends further study and implementation of PSI. (MJK)