Examining the efficiency of schedules of distributed retrieval practice.

Given that students typically have a sizeable amount of course material to learn but a finite amount of study time, evaluating the efficiency of study schedules is important. We explored the efficiency of various schedules of distributed retrieval plus restudy. Across two experiments, 227 undergraduates were asked to learn Swahili-English vocabulary word pairs. In conventional schedule groups, all items were presented for 3 practice trials after initial study (as in most previous research). In dropout schedule groups, the number of practice trials allocated to each item varied, in that practice with a given item was discontinued after criterion performance had been reached. A dropout schedule led to levels of performance similar to those for conventional schedules (but in fewer trials), and it was particularly effective for learning initially incorrect items. However, the efficiency of the various schedules depended critically on the interval between presentations of an item. Results suggest that dropout can be a more efficient learning schedule for students than can conventional schedules of practice.