What is interleaving?
Interleaving is a practice order. Blocked practice looks like A-A-A, then B-B-B. Interleaved practice looks like A-B-C-A-B-C, so you cannot assume the next problem uses the same method as the last one.
In a classroom math study, Rohrer, Dedrick, Hartwig, and Cheung had classes practice either in blocks or mixed over four months. One month later, the interleaved classes scored 61 percent and the blocked classes scored 38 percent.
How is this different from spacing?
Spacing is the gap between sessions. Interleaving is the mix inside a session. A 25-minute Pomodoro can be one mixed set. Spaced repetition decides which day that set comes back. Use both.
The six-step interleaving workflow
- Learn one method briefly. Do a few worked examples of a new procedure until you can finish one without the notes.
- Add a second method. Pick a related method an exam might confuse with the first, such as two formulas that look alike.
- Mix the set. Shuffle so the same method does not appear twice in a row. A page of “section 4.2 only” is still a block.
- Name the method first. Write the method name before any calculation. That is the decision the exam will require.
- Check the choice. Mark a wrong method even if the arithmetic happened to be tidy. Mark a right method even if you slipped on a sign.
- Repeat on a later day. Bring the same mixed set back after a gap. Do not “fix” a low score by blocking that one type for an hour.
What does one set look like?
Blocked: four slope problems, then four area problems.
Interleaved: slope, area, slope, area. Before each one, write “slope” or “area.”
Check: you called a slope problem an area problem. That miss matters more than a tidy wrong number.
When should you still block?
A procedure you have never used can start as a short block. Switch to a mix once you can complete one example. A meta-analysis by Brunmair and Richter found a moderate overall benefit of interleaving, larger when the categories are easy to confuse. Mixing unrelated subjects at random is not the same idea.
What mistakes waste the mix?
- Shuffling topics you cannot tell apart yet, then guessing.
- Keeping the textbook section title visible, which labels the method for you.
- Scoring only the final answer and ignoring a wrong method choice.
- Going back to a long block every time the mix feels slow.
How can an app hold the mixed set?
Put each problem type into Feynman AI as a question, then practice them in mixed order with the source hidden. The study session planner can keep one sitting short enough that you finish the mix instead of rereading one chapter.
Frequently asked questions
What is interleaving?
Interleaving means mixing different kinds of problems or topics in one practice set. Blocked practice does all of one kind before the next.
Is interleaving the same as spaced repetition?
No. Spacing is the time between sessions. Interleaving is the mix of topics inside a session. You can do both.
When does interleaving help?
It helps most when you must choose among similar methods, as on a math test. A brand-new procedure can start with a short block, then move into a mix.
Why does blocked practice feel better?
The last problem tells you the method, so practice feels smooth. An exam does not label the method for you.
Sources
- Rohrer, Dedrick, Hartwig, and Cheung, 2020. Journal of Educational Psychology. A classroom test of interleaved mathematics practice. One month later, interleaved classes scored 61 percent and blocked classes scored 38 percent.
- Brunmair and Richter, 2019. Similarity matters: a meta-analysis of interleaved learning. Educational Psychology Review.
Related guides
Mix the set before you feel ready
Name the method, then answer. The slow choice is the skill the test scores.
Open the study session planner