What Research Shows About the Most Effective Study Techniques

The Techniques With the Strongest Evidence

A review published in Psychological Science in the Public Interest and led by John Dunlosky and Katherine Rawson of Kent State University, with co-authors Elizabeth Marsh, Mitchell Nathan and Daniel Willingham, evaluated widely used study strategies for how well they hold up across learners and subjects. Two methods received the top rating: practice testing, which means quizzing yourself with flashcards or textbook questions instead of just reading, and distributed practice, which means spacing study sessions out over days or weeks rather than cramming.

Why Common Habits Fall Short

The same review rated five frequently used techniques as low utility, including summarization, highlighting, underlining and rereading, according to the Kent State summary of the findings. The researchers noted that these methods remain popular partly because they feel productive, even though they do little to strengthen the kind of retrieval that supports long-term retention.

Mixing Topics: The Case for Interleaving

A 2021 study by Jason Samani and Steven C. Pan, published in npj Science of Learning, tested interleaved homework — alternating between different physics topics instead of finishing one topic before moving to the next — in an introductory physics course for life-sciences majors at UCLA with 350 students enrolled.

On surprise tests given later, students who did interleaved homework scored a median of 50% higher in one stage of the study and 125% higher in a second stage compared with students who used blocked, single-topic homework. The effect sizes the authors reported were 0.40 and 0.91. Students also remembered formulas better after interleaved practice, even though they rated interleaving as more difficult at the time.

Why Harder Feels Like It's Working: Desirable Difficulty

A 2015 study by Geoffrey Maddox and David Balota, published in Memory & Cognition, examined why spacing out retrieval attempts helps. Testing a piece of information three times with gaps between attempts improved long-term retention by 11 to 15 percentage points compared with testing it once, and spaced testing beat cramming the same number of attempts close together. The study's statistical analysis found a larger spacing effect for older adults, averaging about 16 percentage points, compared with about 6 percentage points for younger adults.

The researchers linked this to a concept called desirable difficulty: when retrieving information takes more effort, the memory trace that forms afterward tends to be stronger. The study also found diminishing returns after about three successful spaced retrievals, meaning extra repetition beyond that point added little.

How to Apply This to a Study Schedule

1. Replace rereading notes with active self-testing: close the book and answer questions from memory, then check what was missed.
2. Spread study sessions across several days instead of one long session before a test, following the spacing pattern described by Dunlosky and colleagues.
3. Within a session, mix problem types or topics rather than finishing one topic before starting the next, as tested by Samani and Pan in the physics course.
4. Expect spaced or mixed practice to feel harder than cramming or blocked practice — Maddox and Balota's findings suggest that extra effort during retrieval is linked to stronger long-term memory, not a sign the method isn't working.
5. Limit repetition once retrieval succeeds a few times with gaps in between; the 2015 study found little added benefit beyond about three spaced successes.