The Alfred P. Sloan Foundation Personalized System of Instruction (PSI) project developed 17 courses in various fields at the University of Texas from January 1, 1973 through December 31, 1975. Data collected on comparisons between PSI students and control students indicated that: (1) PSI students learned as much or more than others; (2) Higher PSI grades in this study were not justified; (3) PSI students did not do better in subsequent courses; (4) The majority of PSI students improved their study habits; and (5) Knowledgable teachers can utilize well-developed PSI material in other locales. It was also found that if proctors were paid, PSI course costs were higher than for conventional instruction. If proctors were not paid, only the first units cost more. Further cost studies were recommended. An easy first unit, weekly reinforcement, and rapid course revision were recommended to minimize student procrastination. (Author/NR)