Amount and distribution of study in a personalized instruction course and in a lecture course.

The authors compared two college courses. One used Keller's Personalized System of Instruction (PSI). The other used regular lectures.

Both groups had the same teacher and the same final exam. The researchers tracked how long each student studied and when they studied.

PSI students scored a little higher on the final exam. Both groups spent the same total time studying.

PSI kids spread their work out evenly across the term. Lecture kids crammed right before tests.

Robertson et al. (2013) also held time constant. They found that 3-minute drill sessions beat mixed flash-cards. Both studies show that how you use fixed minutes matters more than simply adding minutes.

Nangle et al. (1993) showed that letting students track their own work boosted math scores. PSI adds another layer: students move ahead only after they master each unit. Together, the papers say self-paced plus self-monitoring equals steadier gains.

Murdoch et al. (2024) used data cycles to fix literacy in grade school. Born et al. (1974) did the same for college science fifty years earlier. The thread: keep checking small units of learning and adjust quickly.

You can run a PSI-style unit without new software. Break your lecture into short mastery quizzes. Let students take each quiz until they pass. You will see fewer cram sessions and slightly higher test scores without adding class time.