Science-Based Study Strategies That Actually Improve Exam Performance

Students preparing for major exams often default to rereading notes, highlighting textbooks, or pulling all-nighters before test day. Controlled studies in cognitive and educational psychology have tested these habits against alternatives and found consistent differences in how well information is retained and recalled under exam conditions.

What the Largest Review of Study Techniques Found

In 2013, psychologists John Dunlosky, Katherine Rawson, Elizabeth Marsh, Mitchell Nathan and Daniel Willingham published a review in Psychological Science in the Public Interest evaluating ten widely used learning techniques. The review rated each technique's utility based on evidence that it works across different subjects, ages and ability levels, and whether it can be implemented without extensive training.

Two techniques received the review's top rating: practice testing (quizzing yourself on material) and distributed practice (spreading study sessions across time instead of cramming). The authors reported that both techniques benefited students of many different ages and ability levels across diverse subject areas.

Several more familiar habits scored lower. The review found that underlining, rereading material and using keyword mnemonic devices received a notably low utility rating — difficult to apply consistently and prone to producing uneven results.

Interleaving: Mixing Topics Instead of Blocking Them

Interleaving means arranging practice so that different problem types or topics are mixed together, rather than drilling one type repeatedly before moving to the next. Psychologists Kelli Taylor and Doug Rohrer tested this in a 2010 study with fourth-grade students practicing math problems. Students who used interleaved practice scored 77% correct on a test given one day later, compared with 38% for students who had practiced the same problems in blocks by type, according to the study summarized on retrievalpractice.org.

Rohrer, the study's co-author, has described the mechanism as teaching students 'how to choose strategies, not just how to use strategies' — because mixed practice forces the learner to first identify what kind of problem they are facing, a skill that plain repetition does not build.

Why Sleep Before and After Studying Matters

A 2021 meta-analysis in Psychological Bulletin by Newbury and colleagues pooled data from 45 reports covering 1,616 participants on sleep deprivation after learning, and 31 reports covering 927 participants on sleep deprivation before learning.

The analysis found that sleep loss after studying produced a small-to-medium memory impairment (Hedges' g = 0.277). The effect was larger when memory was tested immediately after sleep loss (g = 0.410) than after a later recovery sleep (g = 0.176), suggesting a missed night can partly be offset by sleeping before the exam rather than right after the exam. Sleep loss before learning showed an even larger effect (g = 0.621), which the researchers linked to sleep's role in preparing the brain for new learning the following day.

Putting It Into an Exam-Prep Routine

1. Start weeks, not days, before the exam, and schedule short review sessions spread across that period instead of one long session — this is the distributed-practice effect documented by Dunlosky et al. (2013).
2. Replace passive rereading with self-testing: close the book and write out or recite answers from memory, then check them against the source material.
3. When reviewing multiple topics, mix them within a single session instead of mastering one topic before moving to the next, following the interleaving method tested by Taylor and Rohrer (2010).
4. Protect sleep in the days leading up to the exam, since the Newbury et al. (2021) meta-analysis found sleep loss before learning carries a larger measured impairment than sleep loss after it.
5. If a late study session happens, prioritize sleeping afterward rather than staying awake, since the same meta-analysis found impairment was smaller when recovery sleep followed before testing.

Techniques to Scale Back

The Dunlosky et al. (2013) review does not claim these methods are worthless, only that evidence for their effectiveness is weaker and less consistent than for practice testing and spacing. Highlighting a textbook, rereading a chapter, or relying on a keyword mnemonic may still support light review, but the review's authors found these approaches harder to apply in a way that reliably improves test performance.