The interleaving benefit is not caused by spacing, and the benefit extends to delayed tests¶

Claim · All claims
Evidence · 1 study · quant-synthesis r2 · q2
Currency · newest study 2021 · checked against its sources 2026-10-20 (automated, 1 of 1 entry) · not reviewed by a person

Subclaims¶

q2 i? Studies holding spacing constant across interleaved and blocked conditions found the interleaving benefit persists, and delayed-test studies found no significant interaction between schedule and immediate/delayed testing. → Jonathan Firth 2021

Evidence¶

Jonathan Firth 2021¶

Jonathan Firth, Ian Rivers and James Boyle. (2021). A systematic review of interleaving as a concept learning strategy. Review of Education. https://doi.org/10.1002/rev3.3266

q2 · i? · quant-synthesis · r2

Narrative synthesis of seven studies with longer retention intervals (24 hours to 10 days); Zulkiply (2013) and the Carvalho and Goldstone studies directly compared immediate versus delayed retention. The review concludes interleaving "is not an artefact of the spacing effect" and its advantages "can persist across educationally relevant timescales".

"While performance was (unsurprisingly) somewhat worse after a delay, all three of these studies found no significant interactions between interleaving and an immediate/delayed condition."

Discussion¶

Related Claims¶

• The test benefit of interleaved practice does not diminish over time and perhaps grows larger (d = 0.79 at 30 days) — a narrower finding that bears on this claim
• Interleaving category examples improves inductive category learning for visual and mathematical materials, but not for expository texts or word categories — a broader claim this one bears on
• Interleaved practice produces higher mathematics test scores than blocked practice in a classroom experiment — a narrower finding that bears on this claim
• Interleaved practice provided near immunity against forgetting over a 30-fold increase in test delay — a narrower finding that bears on this claim
• Interleaving Improves Discrimination — related
• At a 1-day test delay, interleaved practice yields a moderate benefit over blocked practice (d = 0.42) — a narrower finding that bears on this claim
• Inserting trivia questions between interleaved exemplars impairs inductive learning when it disrupts juxtaposition of categories, with total spacing held constant — related
• When trivia questions space out exemplars, spacing and interleaving are subadditive: interleaving beats blocking only with contiguous presentation, and spacing helps blocked but not interleaved study — related
• Interleaved practice improves delayed posttest performance compared with blocked practice — a narrower finding that bears on this claim
• Interleaving benefits low-skilled students more than high-skilled students when learning math problem categories — related
• Alternating example-practice pairs produce faster and more accurate near-transfer solutions than blocked presentation of examples followed by practice — 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
• When exemplars are already interleaved, larger temporal spacing between same-category exemplars yields better inductive learning than smaller spacing — related
• Interleaving is more effective for materials with a low degree of discriminability — related
• Perceived learning is higher for blocked than interleaved practice at onset but increases over time for interleaved practice only — related
• In Experiment 2, the interleaving benefit on actual test outcomes was not statistically significant, unlike in Experiment 1 — a narrower finding that bears on this claim
• Interleaved practice yields lasting learning effects at delayed posttests in spelling and second-language grammar — a narrower finding that bears on this claim