Interleaving
Mix different problem types in a session instead of doing them in blocks.
Key takeaways
- What it is: Mix different problem types in a session instead of doing them in blocks.
- Why it works: Practicing one type of problem in a long block lets you reuse the same approach mechanically without choosing it, so you never learn which strategy fits which situation. Interleaving forces you to discriminate between problem types and retrieve the right approach each time, which is the skill you actually need when problems arrive unsorted in the real world.
- Evidence: Backed by randomized trials / meta-analyses.
- Avoid: Blocking practice by topic because it feels smoother and produces quick within-session gains, while undermining the durable, transferable learning that interleaving builds.
Why it works
Practicing one type of problem in a long block lets you reuse the same approach mechanically without choosing it, so you never learn which strategy fits which situation. Interleaving forces you to discriminate between problem types and retrieve the right approach each time, which is the skill you actually need when problems arrive unsorted in the real world.
How to do it
- 1Mix related but different topics or problem types within a single study session.
- 2Resist the urge to fully master one type before switching; switch while it still feels unsteady.
- 3Practice identifying which kind of problem you face, not just executing a known procedure.
What the evidence says
RCT / meta-analysisControlled studies, including in mathematics learning, find that interleaved practice produces better long-term performance and transfer than blocked practice, even though it feels harder and worse during practice.
Honest caveat: Interleaving works best among related material where discrimination matters; mixing wholly unrelated topics, or interleaving before any basics exist, can be unhelpful.
- — Rohrer & Taylor (2007), interleaved vs blocked mathematics practice, Instructional Science
Common mistake
Blocking practice by topic because it feels smoother and produces quick within-session gains, while undermining the durable, transferable learning that interleaving builds.
IX Coach mixes practice types so you have to recognize and choose the right approach each time, rather than coasting through one block on autopilot.
Practice this with IX Coach →