Interleaved mathematics practice is effective and feasible

Every school day, many millions of mathematics students complete a set of practice problems that can be solved with the same strategy, such as adding fractions by finding a common denominator. In an alternative approach known as interleaved practice, practice problems are arranged so that no two consecutive problems can be solved by the same strategy, and this approach forces students to choose an appropriate strategy for each problem on the basis of the problem itself. Previous small-scale studies found that practice assignments with a greater proportion of interleaved practice produced higher test scores. 

This study assessed the efficacy and feasibility of interleaved practice in a naturalistic setting with a large, diverse sample. Each of 54 7th-grade mathematics classes periodically completed interleaved or blocked assignments over a period of 4 months, and then both groups completed an interleaved review assignment. One month later, students took an unannounced test, and the interleaved group outscored the blocked group, 61% versus 38%, d = 0.83. Teachers were able to implement the intervention without training, and they later expressed support for interleaved practice in an anonymous survey they completed before they knew the results of the study. Although important caveats remain, the results suggest that interleaved mathematics practice is effective and feasible.