What Research Actually Shows About Effective Study Techniques

Many students spend hours highlighting textbooks, rereading notes and writing summaries before exams. Research in cognitive psychology suggests that time could often be better spent elsewhere. A widely cited 2013 review in the journal Psychological Science in the Public Interest, led by John Dunlosky and Katherine A. Rawson of Kent State University together with researchers from Duke, the University of Wisconsin-Madison and the University of Virginia, evaluated ten common study techniques for their proven usefulness.

The two techniques with the strongest evidence

Of the ten strategies reviewed, only two received the highest 'utility' rating: practice testing and distributed practice. Practice testing means actively retrieving information from memory — through flashcards, self-quizzing, or answering practice questions — rather than simply looking material over again. Distributed practice means spreading study sessions out over days or weeks instead of concentrating them into one block, such as before an exam.

The Association for Psychological Science, which published a summary of the review, states that these two methods consistently improve performance across many types of tests and work for learners of different ages and ability levels.

Why rereading and highlighting fall short

The same review rated highlighting, underlining, rereading and summarization as having low utility. According to the Association for Psychological Science, Dunlosky said: 'I was shocked that some strategies that students use a lot — such as rereading and highlighting — seem to provide minimal benefits to their learning and performance.' The review attributes part of this gap to teacher-training materials, which the authors say rarely cover the more effective but less familiar techniques.

How spacing and retrieval work in the classroom

The Australian Education Research Organisation (AERO), a government-funded research body, published a practice guide stating that spacing and retrieval practice can improve students' long-term retention of what they learn. The guide notes that the exact gap between an initial lesson and a follow-up retrieval session matters less than simply ensuring some delay exists — any spaced review tends to outperform cramming all learning into a single session.

AERO's guide also recommends that retrieval practice works best when students are not being formally assessed on their recall, describing it as a chance for students to retrieve learning in a way that is challenging but low-stakes, for example through bell-ringer questions or exit tickets rather than separate graded quizzes.

Mixing topics: interleaved practice

A related technique, interleaved practice, involves mixing different types of problems during study rather than practicing one type repeatedly in a block (known as 'blocked practice'). Retrievalpractice.org, a research-based teaching resource run by cognitive scientist Pooja Agarwal together with researchers Doug Rohrer and Robert Dedrick, cites a study by Taylor and Rohrer in which fourth-grade students who practiced interleaved math problems scored nearly double on a later exam (77%) compared with students who used blocked practice (38%).

The site notes that interleaving can initially make practice feel harder and performance look worse, but long-term retention improves because students must learn to distinguish between similar problem types rather than following one repeated procedure.

What this means for students

• Spacing out review sessions over days tends to beat last-minute cramming for long-term retention, according to AERO's guide.
• Self-testing — even informally, with flashcards or practice questions — is rated as more effective than rereading or highlighting, per the Dunlosky review.
• Mixing problem types during practice (interleaving) can feel harder in the moment but is linked to better performance on later exams, per the Taylor and Rohrer study cited by Agarwal's team.
• Techniques many students rely on by habit, such as highlighting and summarizing, received the lowest utility ratings in the 2013 review.