What does research say are the best study techniques?
Two techniques stand out: practice testing (trying to recall information from memory) and distributed practice (spreading study across separate sessions). Both have been tested with many ages, materials and test types. Popular habits such as rereading and highlighting have much weaker support.
This page summarizes the main evidence, what it measured, and where it stops.
What was studied
The Dunlosky review of ten techniques
Dunlosky and colleagues (2013) reviewed ten learning techniques that students can use on their own. They rated each one by whether its benefits held across learning conditions, student characteristics (age, ability, prior knowledge), materials, and kinds of tests. This was a narrative review of existing studies, not a new experiment.
Retrieval practice experiments
Karpicke and Roediger (2008) had university students learn foreign-language vocabulary pairs. After a student recalled an item correctly, it was either studied again, tested again, or dropped. Two later meta-analyses pooled many testing studies: Rowland (2014) compared testing with restudying, and Adesope, Trevisan and Sundararajan (2017) compared practice tests with restudying and other activities.
Spacing studies
Cepeda and colleagues (2006) pooled 839 assessments of spaced practice from 317 experiments, mostly verbal recall tasks such as word lists and facts. A follow-up study by Cepeda and colleagues (2008) taught more than 1,350 people a set of facts, gave a review after a gap of up to 3.5 months, and tested them up to a year later.
What it found
Practice testing and spacing rated highest
In the Dunlosky review, practice testing and distributed practice were the only two techniques rated high utility. Elaborative interrogation (asking "why is this true?"), self-explanation and interleaved practice (mixing problem types) were rated moderate. Summarization, highlighting, the keyword mnemonic, imagery for text and rereading were rated low.
| Technique |
Dunlosky rating |
What it looks like |
| Practice testing |
High |
Flashcards, past exams, closed-book recall |
| Distributed practice |
High |
Reviewing the same topic on separate days |
| Elaborative interrogation |
Moderate |
Asking and answering "why is this true?" |
| Self-explanation |
Moderate |
Explaining each step to yourself |
| Interleaved practice |
Moderate |
Mixing problem types in one set |
| Summarization |
Low |
Writing summaries of a text |
| Highlighting |
Low |
Marking key passages |
| Rereading |
Low |
Reading notes or chapters again |
Retrieval beats rereading after the learning feels done
In the Karpicke and Roediger experiment, repeated studying after items were learned had no effect on delayed recall, while repeated testing had a large positive effect. Students' predictions of how well they would do did not match their actual performance. Rowland's meta-analysis found that recall tests produced larger benefits than recognition tests such as multiple choice, and Adesope's found practice tests more beneficial than restudying and every other comparison condition, with effects varying by test format, learners and study design.
The best gap depends on how long you need to remember
Cepeda's 2006 meta-analysis found that the gap giving the best retention grew as the retention interval grew. In the 2008 study, the best gap was roughly 20 to 40 percent of the time until a test one week away, falling to about 5 to 10 percent for a test one year away. For a test a week away, that works out to a review roughly one to three days after first study. For knowledge you want in a year, gaps of several weeks fit better.
How big are the effects?
The meta-analyses report average effects across many studies rather than one number you can expect. What is consistent is the direction: in every pooled comparison above, retrieval and spacing did better than simply studying again. The advantage tends to show up most on delayed tests, days or weeks later, which is the situation that matters for exams and for knowledge you want to keep. On a test a few minutes after studying, rereading can look just as good, which is part of why it stays popular.
Where the moderate techniques fit
The three moderate-rated techniques are worth knowing because they suit particular jobs. Elaborative interrogation, asking "why would this be true?", fits fact-heavy reading. Self-explanation, talking yourself through each step, fits worked examples in math and science. Interleaving, mixing problem types, helps you learn which method a problem needs, which blocked practice of one type at a time does not train. The 30-day study habit plan adds each of these in week three, after recall and spacing are already in place.
What it does not show
- It is not a ranking for every subject. Most studies used word lists, facts, and short texts. Evidence is thinner for complex skills such as proofs, essays or lab work, and the Dunlosky authors noted that several moderate-rated techniques had not been adequately tested in real classrooms.
- Low utility does not mean useless. Summarizing helped some students on some tests. The rating reflects how consistently a technique helped across conditions, not whether it can ever help.
- Effect sizes are averages. Meta-analyses pool very different studies. Your gain from any one technique may be larger or smaller.
- The exact spacing numbers come from fact learning. The 2008 percentages are a rough guide, not a formula for every course.
- These studies measure memory and test scores, not habits. They do not show how to get yourself to study in the first place. For that, see how to build a study habit and how to stop procrastinating on studying.
Practical takeaways
- Start each session with recall. Close your notes and write what you remember, then check. The 30-day study habit plan opens every session this way.
- Test with free recall where you can. Writing an answer from memory is more effortful than picking from options, and recall tests showed larger benefits in the research above.
- Review on separate days. Set review dates of about one day, three days and a week for material you need soon. The study schedule maker sets these dates for you.
- Replace rereading, do not add to it. Use the time you would spend rereading on practice questions instead.
- Mix problem types once basics are in place. Interleaving has moderate support and fits math and science problem sets well.
- Do not trust how learning feels. Rereading feels fluent; recall feels hard. The Karpicke and Roediger students misjudged their own recall, so check with a quiz.
To turn these into a daily routine, build a personal study plan, read how to make a study session specific, or browse the studying and focus hub.
