How to study effectively: what the research says works best

How to study effectively: the evidence in one page

If you want to know how to study effectively, start with what learning research has tested, not with what feels productive. Decades of experiments point to a short list: test yourself, space your study over time, mix similar topics, explain ideas to yourself, and sleep. The habits most people rely on, rereading and highlighting, sit near the bottom.

This page is the hub of our study science section. It ranks techniques by the strength of their evidence, summarises each one, and links to a full article on every topic. Every claim cites a peer-reviewed paper, and we say where the evidence is weak or mixed. It ends with a concrete protocol for a certification exam using our free practice tests.

The ranking: what the big reviews found

Two reviews anchor the ranking. In 2013, Dunlosky et al., 2013 evaluated ten popular study techniques and rated each by how widely its benefits generalise:

• High utility: practice testing and distributed practice.
• Moderate utility: elaborative interrogation, self-explanation and interleaved practice.
• Low utility: summarisation, highlighting, the keyword mnemonic, imagery for text and rereading.

In 2021, Donoghue & Hattie, 2021 ran a meta-analysis of the same ten techniques: 242 studies, 1,619 effects and 169,179 participants. The overall mean effect was 0.56. Distributed practice (d = 0.85) and practice testing (d = 0.74) came out on top; underlining and summarisation (both d = 0.44) at the bottom.

A word on those numbers. An effect size, d, measures the gap between learners who used a technique and those who did not, in standard deviations. By the usual rule of thumb, 0.2 is small, 0.5 moderate and 0.8 large. So spacing your study has a large effect, and testing yourself is close behind. Two cautions from the authors: most studies measured surface or factual learning, and effects were much greater for lower-ability than higher-ability students. The full table of all ten is in study techniques ranked by evidence.

1. Retrieve: test yourself instead of rereading

Pulling information out of memory strengthens it more than putting it in again. Retrieval practice often produces large gains in long-term retention compared with repeated studying, works even without feedback, and works better with it (Roediger & Butler, 2011).

The classic demonstration: students who took recall tests on prose passages remembered substantially more after 2 days and 1 week than students who restudied, even though restudying won on a test 5 minutes later and made students more confident (Roediger & Karpicke, 2006). In real psychology classes, testing had a moderate advantage, d = 0.56 (Schwieren et al., 2017).

• Active recall: practical retrieval methods, from blank-page recall to self-written questions.
• The testing effect: the research on practice tests, and how many to take before an exam.
• The Leitner system: a simple flashcard box method that combines retrieval with spacing.

2. Space: spread study over days and weeks

The same total study time works better spread out than crammed. A meta-analysis of 317 experiments found that the gap between sessions that maximises retention increases with the time until the test (Cepeda et al., 2006). In a later study with more than 1,350 learners, the optimal gap was about 20 to 40% of a 1-week test delay and about 5 to 10% of a 1-year delay (Cepeda et al., 2008).

This is not just a lab effect. A meta-analysis of classroom studies found a moderate benefit of spaced over massed practice, d = 0.54, larger at higher education levels (Mawson et al., 2025).

• Spaced repetition: the research and a review schedule for exams 1, 4 and 12 weeks away.
• The forgetting curve: what Ebbinghaus and a modern replication really found, and why "you forget 70% in a day" is a myth.
• Study schedule: how to build a plan with review slots built in.

3. Mix: interleave similar topics

Interleaving means mixing different but related topics in one session instead of practising them one at a time. A meta-analysis of 59 studies found a moderate overall benefit, g = 0.42, largest when categories are similar and easy to confuse (Brunmair & Richter, 2019). It is not universal: blocking was better for word lists, and two large classroom experiments on mathematical categories found no effect (Rowlandson et al., 2025).

• Interleaving: when interleaved practice helps, when it does not, and how to use it for exams full of confusable concepts.

4. Understand: explain the why

Two moderate-utility techniques ask you to generate explanations. Elaborative interrogation means asking "why is this true?" and answering it. Self-explanation means explaining how each step or example works; a meta-analysis of self-explanation prompts found g = .55 (Bisra et al., 2018). There are limits: self-explanation suits principle-based material, and explaining your own choices can sometimes reduce learning (Rittle-Johnson & Loehr, 2017).

• Elaborative interrogation: how to use "why" questions and when they work best.
• The Feynman technique: explaining a concept in simple words. It has not been tested under that name, but it combines retrieval with self-explanation.

5. Expect it to feel hard, and judge yourself carefully

The best techniques feel worse while you use them. Desirable difficulties, such as testing, spacing and interleaving, are effortful but improve learning and transfer; learners resist them because effort feels like poor learning (de Bruin et al., 2023). Helpful levers include finding value in the task, reducing its cost, reframing how you read the effort, choosing an appropriate challenge, and giving yourself choice (Zepeda et al., 2020).

Your sense of how well you know something is unreliable. In a survey of 177 students, most reread and relatively few tested themselves (Karpicke et al., 2009). Rereading raises confidence without raising memory (Seban et al., 2024). The picture is not all bleak: when learners imagine a test 1 to 2 weeks away, they often correctly judge testing as better (Weissgerber & Rummer, 2022).

• Desirable difficulties: why harder study often works better, and how to stick with it.
• Metacognition: how to judge what you really know.

6. Memorise: techniques for lists and facts

Some exam content is just facts to memorise. Mnemonics were rated low utility overall by Dunlosky et al., but for the right material they help. The method of loci (memory palace) had a medium effect, g = 0.65, in a meta-analysis of 13 trials, with a high risk of bias (Twomey & Kroneisen, 2021). Six weeks of training in it produced memories that were still better four months later (Wagner et al., 2021).

• How to memorize things fast: which memory techniques have evidence, and how to retain information beyond the exam.

7. Body and attention: sleep, rest and your phone

Sleep. Total sleep deprivation impairs memory, more before learning (g = 0.621) than after (g = 0.277) (Newbury et al., 2021). Restricting sleep to 3 to 6.5 hours, compared with 7 to 11, impairs memory formation, g = 0.29 (Crowley et al., 2024). In adolescents, five nights of 5 hours in bed worsened picture-encoding memory compared with 9 hours (Cousins et al., 2018).

Rest. Brief quiet rest after learning facilitates memory consolidation (Wamsley, 2019).

Phones. An influential study found the mere presence of your own smartphone reduced available cognitive capacity (Ward et al., 2017). A meta-analysis of 56 effects found the effect smaller than claimed: only working memory capacity was significantly and modestly affected (Parry, 2023). Moving the phone away is still a cheap precaution.

• How to focus while studying: distractions, breaks and what the evidence says about each.

8. Exams: preparation, technique and nerves

Putting the techniques together into a plan is where most students fail. Three guides cover it:

• How to study for exams: an 8-week step-by-step process from baseline test to exam day.
• How to pass an exam: exam-day technique, including multiple-choice strategy.
• Test anxiety: a meta-analysis of 44 trials found interventions reduced test anxiety substantially, g = -0.76, and improved performance, g = 0.37 (Huntley et al., 2019). Not every quick fix holds up; see the article for what does.

If you change only one thing

Replace rereading with self-testing. It is the single change with the best ratio of effort to payoff, because it also fixes your biggest blind spot: not knowing what you do not know. Close the book after each section and write down what you remember, or answer a few practice questions before you look at the explanation.

The second change is to schedule reviews instead of hoping memory holds. Put a review of each topic in your calendar about a week after you first study it. Between them, these two changes cover the two high-utility techniques.

Everything else on this page, interleaving, explanation, mnemonics, sleep and focus, makes those two habits work better. None of it replaces them.

What an effective study week looks like

Here is how the principles fit together in an ordinary week for someone studying around a job, at five sessions of about 90 minutes:

• Monday to Thursday: each session opens with 15 minutes of questions on older topics (retrieve, space), then 45 minutes of new material in two blocks with blank-page recall after each (retrieve), a few minutes of quiet rest, and 20 minutes of questions on the day's topic with "why" explanations for each answer (understand).
• Tuesday and Thursday: swap the opening questions for a 20-question set mixing topics you confuse (mix).
• Saturday: a 30 to 40 question timed set across everything so far, then a full review of mistakes (test, space).
• Every night: phone out of the study room during sessions, and a consistent bedtime (body and attention).

Nothing in this week is exotic. The difference from how most people study is what is missing: no rereading sessions, no highlighting, no cramming the day before.

Myths to drop

• Learning styles. Matching study to a "visual" or "auditory" style has virtually no supporting evidence (Pashler et al., 2008); a later review called it a neuromyth (Aslaksen & Lorås, 2018).
• Rereading until it feels familiar. Familiarity is not recall. Rated low utility.
• Highlighting as studying. Among the lowest effects of the ten techniques.
• Cramming works if you're disciplined. It can work for tomorrow's quiz; it does not build memory that lasts to a certification exam weeks away.

Does learning about all this change anything? In one course study, students taught evidence-based strategies used more high-utility strategies and improved by about a third of a letter grade compared with a control semester (Brown-Kramer, 2021).

Limits of the research

Most studies use students, short materials and factual outcomes. Effects on deep, applied understanding are smaller and less studied. Lab results do not always survive real classrooms, as the interleaving studies show. Effects also vary a great deal from study to study: Donoghue and Hattie report high heterogeneity across their 1,619 effects, which means the average effect for a technique hides many smaller and some larger results. Numbers on this page are averages, not guarantees for any one learner. We know of no large trials run specifically with professional certification candidates. Treat the protocol below as our application of the strongest findings, and check it against your own practice test scores.

How to use this for a certification exam

A six-week protocol for a multiple-choice certification exam, at about 8 to 10 hours per week:

1. Day 1: baseline. Take our free practice test for your exam cold, for example the Security+ practice test or the PMP practice test. Note your weakest domains.
2. Each session (retrieve + space): start with 10 to 15 questions on material from 3 to 7 days earlier. End with 5 minutes of blank-page recall on today's topic.
3. New material (understand): after each objective, explain why it works and write 5 questions about it.
4. From week 2 (mix): twice a week, a 20-question set mixing similar topics you confuse.
5. Review timing (space): each topic comes back about a week after first study, again two to three weeks later, and again in the final week.
6. Weeks 4 and 5 (test): one full-length timed mock each week; review every answer and keep an error log.
7. Week 6 (consolidate): daily mixed sets of 20 to 30 questions, error log reviewed twice, last mock at least 3 days before the exam, 7+ hours in bed each night.

Retake the free practice test every two weeks and move study time toward whichever domain is lowest.