Interleaving

Interleaving is the kind of strategy that pupils tell you they hate and the evidence tells you they need. A maths worksheet of twenty questions on the same method feels efficient. The same twenty questions shuffled across three methods feels chaotic. The shuffled version produces more durable learning.

What it is

A practice schedule that mixes different but related problem types within a session, rather than grouping all of one type together. The opposite is blocked practice.

The difference matters most for subjects where pupils need to choose between methods. If every question on the page uses the same method, pupils never have to make that choice.

Why it works

Rohrer and colleagues’ studies in maths show that pupils who interleave perform better on tests, even though they perform worse on the practice itself. The mechanism is partly that interleaved practice forces them to identify the problem type before solving, which is what the exam will ask.

It also pulls on the same spacing mechanism: returning to a method after time away strengthens the memory trace.

How to use it

Once pupils have learnt three or four methods within a topic, build a practice sheet that mixes them. In maths, interleave fractions, decimals, and percentages on one page. In MFL, interleave present, past, and future tense verbs. In science, interleave force, work, and energy questions.

Warn pupils that the worksheet will feel harder, and that the difficulty is the point.

When not to use it

Do not interleave before pupils have learnt the methods. Interleaving works best on familiar content. New content needs blocked practice first.

Related Chalk tools

Worksheet Creator can build interleaved practice sheets that pull from multiple methods. Retrieval Task supports the same shuffling across a unit.