The interleaving benefit appears in three of four problem-type-by-delay comparisons; the slope-problem effect at 1 day was not statistically significant¶

Claim · All claims
Evidence · 1 study (2 entries) · causal r2 · q3 · i2–i3
Currency · newest study 2015 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q3 i2 At the 1-day delay, interleaving significantly benefited graph problems (d = 0.54) but not slope problems (d = 0.43, p = .10). → Rohrer 2015 q3 i3 At the 30-day delay, interleaving significantly benefited both graph problems (d = 0.81) and slope problems (d = 0.87). → Rohrer 2015 (2)

Evidence¶

Rohrer 2015¶

Rohrer, D., Dedrick, R. F., & Stershic, S. (2015). Interleaved practice improves mathematics learning. Journal of Educational Psychology, 107(3), 900-908. https://doi.org/10.1037/edu0000001

q3 · i2 · causal · r2

Secondary analysis splitting test scores by problem type at the 1-day delay, using Welch-corrected t tests. The graph-problem contrast was significant with printed d = 0.54; the slope-problem effect was "positive but not statistically significant" (d = 0.43).

"For the 1-day test delay, interleaved rather than blocked practice resulted in higher mean test scores for the graph problems, 89% (SD = 18%) vs. 73% (SD = 36%), t(50.6) = 2.25, p = .029, d = 0.54, but the effect of interleaved practice on the slope problems was positive but not statistically significant, 73% (SD = 41%) vs. 54% (SD = 47%), t(56.0) = 1.67, p = .10, d = 0.43."

Rohrer 2015 (2)¶

Rohrer, D., Dedrick, R. F., & Stershic, S. (2015). Interleaved practice improves mathematics learning. Journal of Educational Psychology, 107(3), 900-908. https://doi.org/10.1037/edu0000001

q3 · i3 · causal · r2

Secondary analysis at the 30-day delay showed significant interleaving benefits for both problem types, with printed Cohen's d = 0.81 for graph and d = 0.87 for slope problems, both large effects.

"For the test given after a 30-day delay, there was a statistically significant benefit of interleaving for both graph problems 84% (SD = 30%) vs. 54% (SD = 44%), t(56.7) = 3.28, p = .002, d = 0.81, and slope problems, 65% (SD = 43%) vs. 29% (SD = 39%), t(61) = 3.44, p = .001, d = 0.87."

Discussion¶

Related Claims¶

• At a 1-day test delay, interleaved practice yields a moderate benefit over blocked practice (d = 0.42) — related
• Interleaved practice produces higher mathematics test scores than blocked practice in a classroom experiment — related
• Interleaved practice provided near immunity against forgetting over a 30-fold increase in test delay — related
• The test benefit of interleaved practice does not diminish over time and perhaps grows larger (d = 0.79 at 30 days) — related
• Interleaving category examples improves inductive category learning for visual and mathematical materials, but not for expository texts or word categories — related
• The interleaving benefit is not caused by spacing, and the benefit extends to delayed tests — related
• In Experiment 2, the interleaving benefit on actual test outcomes was not statistically significant, unlike in Experiment 1 — related