Spaced Practice and Interleaving of Skills 

Spaced practice means revisiting important ideas over days and weeks instead of teaching them once and moving on. Interleaving means mixing different but related problem types so students must think about which strategy to use. Together, these approaches make learning more durable and flexible than cramming or doing long blocks of one kind of problem. 

Why this matters 

·         Students often “get it” in the moment, then forget it weeks later. Spacing and interleaving are two of the most powerful ways to make learning stick. 

·         Research shows that spreading practice out over time and mixing related problem types improves long term retention compared to massed, blocked practice. 

What it is 

·         Spaced practice: revisiting key ideas spread out over days or weeks instead of teaching and practicing them once and then moving on. 

·         Interleaving: mixing different but related problem types or topics in practice so students must choose which strategy to use, instead of doing many of the same kind in a row. 

Key classroom moves 

·         Use daily or weekly warm-ups to bring back high-priority skills from earlier in the year. 

·         Create practice sets that mix several previously taught problem types, and ask students to explain how they decided which strategy to use. 

·         Plan unit assessments and quizzes so they always include a few items from earlier units (for example, cumulative quizzes). 

·         Teach students simple study habits: shorter sessions over several days and self- testing, rather than one long cram session the night before. 

·         Coordinate across a team or grade level to identify high-leverage skills that will be revisited all year.  

Implications by grade 

Grades K–2

·         Build short review routines (songs, games, flashcards) for letters, sounds, and math facts across the week. 

·         Revisit previously read stories, vocabulary, or number routines regularly instead of only reading them once. 

Grades 3 –5

·         Use spiral review in math and literacy warm-ups that include problems from past units. 

·         Give mixed practice homework occasionally (for example, word problems from different operations in one set). 

Grades 6 –8

·         Include older topics on exit tickets and quizzes so students must recall and apply them without warning. 

·         Teach students how to make and use study calendars that spread practice over several days before tests. 

Grades 9 –12

·         Design cumulative tests or projects that require students to use concepts from earlier in the course, not just the latest unit. 

·         Support students to build spaced study plans before major exams (for example, midterms, finals) instead of last-minute cramming. 

References 

Chen, O., Paas, F., & Sweller, J. (2021). Spacing and interleaving effects require distinct

theoretical bases: A systematic review testing the cognitive load and discriminative -contrast

hypotheses. Educational Psychology Review, 33, 1499 –1522. https://doi. org/10.1007/s10648-

020-09586 -9

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