Interleave topics within a session
Mix related topics in one session instead of doing all of one before the next.
Key takeaways
- What it is: Mix related topics in one session instead of doing all of one before the next.
- Why it works: Switching between topics forces you to repeatedly retrieve and re-select the right approach, which both adds spacing within the session and trains the discrimination skill of knowing which method a problem calls for. Blocking lets you coast on the last answer.
- Evidence: Backed by randomized trials / meta-analyses.
- Avoid: Blocking one topic until it feels mastered, which produces fast in-session fluency but weaker retention and poor strategy selection later.
Why it works
Switching between topics forces you to repeatedly retrieve and re-select the right approach, which both adds spacing within the session and trains the discrimination skill of knowing which method a problem calls for. Blocking lets you coast on the last answer.
How to do it
- 1Shuffle problem types or decks rather than grinding one to completion.
- 2Accept that interleaved practice feels harder and slower — that is the mechanism working.
- 3Group topics that are easy to confuse, so you practice telling them apart.
What the evidence says
RCT / meta-analysisInterleaving improves long-term retention and the ability to choose the right strategy, especially for related categories, shown across controlled studies — though it feels less effective to learners while they do it.
Honest caveat: For wholly unrelated material the benefit is mainly the added spacing; interleaving shines most when items are confusable.
Common mistake
Blocking one topic until it feels mastered, which produces fast in-session fluency but weaker retention and poor strategy selection later.
IX Coach mixes due items across topics in a single sitting so each review carries both spacing and discrimination benefits.
Practice this with IX Coach →