The test benefit of interleaved practice does not diminish over time and perhaps grows larger (d = 0.79 at 30 days)¶

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

Subclaims¶

q3 i2 At a 30-day test delay, interleaved practice showed a large benefit over blocked practice (74% vs. 42%; d = 0.79). → Rohrer 2015 q3 i? The interaction between practice schedule and test delay was not statistically significant, indicating the interleaving benefit did not significantly shrink at the longer delay. → 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

Test given 30 days after the review, with unannounced novel problems of the same format. Interleaved students averaged 74% versus 42% for blocked, with printed Cohen's d = 0.79 (medium-to-large, just under the 0.8 threshold).

"Students tested 30 days after the review showed a large benefit of interleaving, 74% (SD = 39%) vs. 42% (SD = 43%), t(62) = 4.54, p < .001, Cohen's d = 0.79, 95% CI [0.43, 1.15]."

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 · i? · causal · r2

Two-way ANOVA testing whether the interleaving benefit decreased over time. The article reports the schedule-by-delay interaction was not statistically significant, so equivalence of benefit across delays was not established, only the absence of a detected interaction.

"However, the interaction between practice schedule and test delay was not statistically significant, F(1, 124) = 2.84, p = .09."

Discussion¶

Related Claims¶

• Interleaving category examples improves inductive category learning for visual and mathematical materials, but not for expository texts or word categories — the general claim this finding bears on, with the studies behind it
• 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 interleaving benefit appears in three of four problem-type-by-delay comparisons; the slope-problem effect at 1 day was not statistically significant — related
• The interleaving benefit is not caused by spacing, and the benefit extends to delayed tests — a broader claim this one bears on
• Cohen's small, medium, and large effect size benchmarks are arbitrary and should not be interpreted rigidly — related
• In Experiment 2, the interleaving benefit on actual test outcomes was not statistically significant, unlike in Experiment 1 — related