Putting evidence-based claims to the test: A multi-site classroom study of retrieval practice and spaced practice

Retrieval practice and spacing out studying help increase learning. Introductory Psychology students at nine colleges/universities took quizzes with more (RP+) or less (RP-) retrieval practice and more (SP+) or less (SP-) spacing between quizzes. We compared (N = 351) scores on class exams and on a standardized test. We also measured key student variables (e.g., depth of processing). GPA predicted a significant portion of variance in exam scores, R-2 = 0.05, F(1, 204) = 10.84, p = 0.001. We found a main effect for retrieval practice and a significant retrieval by spacing practice interaction, R-2 = 0.28, F(3, 201) = 27.38, p < 0.001. Students using SP+, as well as those with SP- and RP-, scored higher than students using SP- and RP+. In practice, closer attention needs to be paid to quiz and exam content overlap and the duration within which repetition is used.