Interleaving
Why does practice that feels harder produce better results?
The idea
Mixing related problem types trains selection, not just repetition.
In the real world
Alternate margin, cash-flow, and valuation questions.
Going deeper
Blocked practice tells you the method before you start, so you only rehearse execution. Mixed practice forces you to identify which method applies first, which is the step a real problem actually requires.
This is why interleaving feels harder and produces better transfer. Twenty margin problems in a row train the calculation; forty shuffled problems train the recognition and the calculation. Performance during practice is worse, which makes the technique feel ineffective at exactly the moment it is working — a pattern it shares with spacing and retrieval.
Where it stops applying
Interleaving too early, before any single method is understood, produces confusion rather than discrimination. Block first to build the component, then mix to build selection.
Why it matters
Mixing problem types trains you to recognise which approach applies, which is what real situations demand.
Try this today
Mix two skills in the next practice session.
Test yourself
One person does twenty margin problems, then twenty cash-flow problems. Another shuffles all forty. The second finds it harder and scores better later. Why?
Show the answer
Blocked practice tells you the method before you start, so you only practise executing it. Shuffling forces you to identify the problem first, which is the step that is actually required when a problem arrives without a label.
Learn this in the feed Answering from memory, then again days later, is what makes it stick.