Mawson & Kang (2025). The Distributed Practice Effect on Classroom Learning: A Meta-Analytic Review of Applied Research

Reviewed by Tony Ingram, PhD
Review posted August 12, 2025

Full Citation

Mawson, R. D., & Kang, S. H. K. (2025). The Distributed Practice Effect on Classroom Learning: A Meta-Analytic Review of Applied Research. Behavioral Sciences, 15(6), 771. https://doi.org/10.3390/bs15060771

Abstract

There is extensive evidence that distributed practice produces superior learning to massed practice, predominantly from laboratory studies often featuring decontextualized learning. A systematic review of applied research was undertaken to assess the impact of distributed practice on classroom learning. Inclusion criteria were classroom studies with learning materials and timescales relevant to curriculum-based learning. The screening of over 3000 articles resulted in 22 reports containing 31 effect sizes (N > 3000). A meta-analysis found a moderate effect in favor of distributed over massed practice (d = 0.54, 95% CI [0.31, 0.77]). Although a comprehensive quantitative moderator analysis was not possible due to the number of studies, generally larger effect sizes were associated with studies that featured longer retention intervals, had learners at higher education levels, and had fewer re-exposures to the materials.

Key Results

Note that reliability here refers to the certainty of the result (terminology likely to change in a future site update).

Result Name

Effect Size

Reliability

Overall (Spaced vs. Massed)

Medium

High

Sub-analysis: Learning Domain — Accounting

Sub-analysis: Learning Domain — Critical Thinking

Sub-analysis: Learning Domain — History

Sub-analysis: Learning Domain — Language

Sub-analysis: Learning Domain — Math

Sub-analysis: Learning Domain — Reading

Sub-analysis: Learning Domain — Science

Sub-analysis: Learning Domain — Spelling

Sub-analysis: Learning Domain — Teacher Education

Study Characteristics

Learning Domain	Declarative Learning
Study Topic	Massed Practice, Spaced Practice
Study Type	Membership Required
Task Studied	Membership Required
Subject Type	Membership Required
Number of Studies	Membership Required
Quality Score (%)*	Membership Required

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* Study quality assessed using JBI Systematic Review Checklist.

Reviewer Notes

Mawson & Kang (2025) is the real-world meta-analysis on spaced practice for declarative learning we’ve needed since Cepeda. Instead of contrived lab word lists with seconds-long lags, they review classroom studies (history, math, etc.) on sensible, multi-day timescales. The result: 22 studies (31 effects; N > 3,000) and a medium, reliable spacing advantage (d = 0.54, 95% CI [0.31, 0.77]). They also report subject-level sub-analyses.

Overall, spacing works to improve retention when learning across most classroom subjects. Effects tended to be larger with longer retention intervals, higher education levels, and fewer restudies. Translation: spacing shines when you need to remember something for longer (weeks to a month); the advantage trends bigger in secondary/university samples; and the spacing advantage shrinks as you restudy the same material many times. If you must cram, heavy restudy (3 or more times reviewing the same material) can compensate — but it’s inefficient.

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Mawson & Kang (2025). The Distributed Practice Effect on Classroom Learning: A Meta-Analytic Review of Applied Research

Table of Contents

Full Citation

Abstract

Key Results

Study Characteristics

Reviewer Notes

Link to Study

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