Evidence-Based Studying Part 1 - Shuffle the Deck: Why Mixing Topics Beats One-System Study Days
I went down a rabbit hole on the research behind how we study, and built the best of it into a 5-step system. This post covers one piece. Watch the full breakdown in this video.
-Simon
Your Q-bank called. It wants to be set to random.
Studying one system at a time is comfortable, and it’s costing you marks. Interleaving means mixing your topics in a varied order instead of working through them in tidy blocks. Two groups of medical students learned ECG interpretation from identical tracings, and the shuffled group came out ahead on brand new ECGs. Only the order changed.
That was 2003, and the finding has since been replicated in a different city with a different imaging modality. So why do most study schedules still get built the other way? Blocked practice produces a deep, immersed focus that feels like progress, which is a poor guide to whether anything is being stored. Starting with your next block, set your Q-bank to random instead of choosing a system.
In 2003, Hatala, Brooks and Norman studied medical students learning ECG interpretation. They compared mixed practice, with diagnoses shuffled case by case, against blocked practice, one diagnosis at a time. They found the mixed group scored 16 percentage points higher on novel tracings. Rozenshtein and colleagues repeated the design in 2016 with 40 medical students and chest X-rays, and the interleaved group again finished 14 points ahead.
HOW TO MIX
• Shuffle 3 decks together
• No more than 3 same-topic cards in a row
• Pair the mimics: hives beside cellulitis
• Set the timer, not the topic
It can be easy to do this incorrectly. For example:
• shuffling so aggressively that no topic gets enough contact to form a pattern
• mixing topics that share no decision point, since interleaving earns its keep on conditions you could confuse.
Scaffolding is learning a topic that relates to a topic that you already know, and can help you take this up a notch. Gout next to septic joint teaches you something – find the similarities (and more importantly, focus on how they’re different!) However, gout next to otitis media teaches you much less.
Exam tip: interleaving works because it forces you to discriminate between conditions that look alike, so build your blocks around mimic pairs rather than single systems. At first this will seem harder than blocked studying - but that’s precisely the skill a SAMP (Select-Answer Management Problem) asks for when two plausible diagnoses sit inside the same stem. The splitter feature between a mimic pair is the kind of detail that could show up there.
What do attendees say about The Review Course?
“Fantastic way to review and quickly identify areas needing more focused study” - Dr. IM, The Review Course 2025 attendee.
References
Hatala, Brooks & Norman (2003). Medical students (per-arm n not reported): mixed versus blocked ECG practice, 46% versus 30% accuracy on novel ECGs (p<.05). https://doi.org/10.1023/A:1022687404380
Rozenshtein et al. (2016). n=40 Y1 to Y2 medical students: interleaved versus massed chest X-ray teaching, 57% versus 43% overall (p<.05). https://doi.org/10.1016/j.jacr.2016.03.031
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