Between the spring of 1970 and the summer of 1974, 1,747 students enrolled in Math X, a multilevel PSI (Personalized System of Instruction) type of open-ended mathematics instruction system at Antelope Valley College. Results of a study designed to evaluate the course by comparing it with the more conventional mathematics lecture course indicated that: (1) students who had enrolled in Math X completed fewer units; (2) fewer students received success grades in Math X than in conventional lecture classes; (3) Math X students had a higher grade point average; (4) students who earned low or nonsuccess grades in Math X went on to do better in conventional classes, whereas students who earned high grades in Math X tended not to do as well in conventional math classes; (5) Math X instruction cost approximately three percent less than conventional instruction; (6) only 38% of lecture-only students continued to study math, while over 52% of those exposed to Math X did so. Results of a questionnaire sent to 300 Math X students (30% response) indicated that students believed Math X to be about as difficult as other math courses, that most respondents would repeat Math X for more advanced study if such were offered, and that most would be interested in classes in other subjects taught using the same format. (DC)