How to Study Effectively: 5 Techniques Ranked by Science

Most students study wrong. Not because they're lazy—because no one taught them how. They reread textbooks, highlight paragraphs, and cram the night before. It feels productive. The research says it's nearly worthless.

In 2013, a team of cognitive psychologists led by John Dunlosky evaluated 10 common study techniques across hundreds of experiments. Their findings, published in Psychological Science in the Public Interest, showed that the methods most students use—rereading, highlighting, summarizing—ranked among the least effective. The techniques that actually work? Most students have never tried them.

Here are the five study methods that science says work best, ranked from most to least effective—with exact steps to start using each one today.

The Dunlosky Rankings: What Actually Works

Dunlosky et al. (2013) rated each technique based on four criteria: generalizability across ages, materials, and conditions; evidence from controlled experiments; whether it works in real classroom settings; and durability of the learning effect.

Study Techniques Ranked by Effectiveness (Dunlosky et al., 2013)

Rank	Technique	Effectiveness	How Most Students Use It
1	Practice Testing	High	Rarely—only before exams
2	Distributed Practice	High	Rarely—most students cram
3	Elaborative Interrogation	Moderate	Sometimes, when curious
4	Self-Explanation	Moderate	Rarely
5	Interleaved Practice	Moderate	Almost never
6	Summarization	Low	Often
7	Highlighting	Low	Constantly
8	Rereading	Low	Constantly

Notice the pattern? The most popular study methods are the least effective. The most effective methods are the least used. That's not a coincidence—the techniques that work feel harder, which makes students avoid them. But that difficulty is exactly why they work.

#1: Practice Testing (Active Recall)

Rated: High utility. Self-testing is the single most effective way to study. It outperforms every other technique across virtually every subject, age group, and testing format.

Roediger and Karpicke (2006) showed that students who took a practice test after reading a passage remembered 80% more after one week than students who spent the same time rereading. The act of pulling information from memory—rather than passively reviewing it—creates stronger, more durable memory traces.

How to do it

1. After reading a chapter, close the book. Write down everything you remember on a blank page.
2. Check what you missed. Focus your next study session on those gaps.
3. Use flashcards for factual material—but test yourself, don't just flip and read.
4. If your textbook has practice questions, do them before rereading the chapter, not after.

The key insight: getting answers wrong still improves learning. Kornell, Hays & Bjork (2009) found that unsuccessful retrieval attempts followed by feedback produce better retention than skipping the question entirely. Don't avoid testing yourself because you're afraid of failing—failing is part of the mechanism.

For a deep dive on this technique, see our full guide to active recall.

#2: Distributed Practice (Spaced Repetition)

Rated: High utility. Instead of studying everything in one marathon session, spread your study across multiple shorter sessions over days or weeks. This is the antidote to cramming—and it's backed by over 130 years of research.

Cepeda et al. (2006) analyzed 184 research articles covering 14,000+ participants and found that spaced practice improved long-term retention by 10-30% compared to massed practice (cramming). The effect was consistent across ages, subjects, and time scales.

The underlying mechanism is the forgetting curve, discovered by Hermann Ebbinghaus in 1885. Memory decays exponentially after learning—you forget roughly 70% within 24 hours without review. But each time you review at the right moment, the curve flattens. The memory lasts longer and longer until it becomes essentially permanent.

How to do it

1. Never study a topic in a single session. Break it into 3-4 shorter sessions across a week.
2. Review new material after 1 day, then 3 days, then 7 days, then 14 days.
3. If an exam is 30 days away, start studying on day 1—not day 25.
4. Use a calendar or an app to schedule review sessions so you don't have to rely on willpower.

Cramming vs. Spaced Study: What the Research Shows

Metric	Cramming (1 session)	Spaced Study (4 sessions)
Performance on next-day exam	Similar	Similar
Performance after 1 week	~35%	~60%
Performance after 1 month	~15%	~50%
Long-term knowledge retention	Nearly zero	Substantial

Cramming "works" for tomorrow's exam, which is why students keep doing it. But if you want to actually know the material in a month—for a final exam, for your career, for life—spaced practice is the only method that delivers.

Read the full breakdown in our guide to spaced repetition.

#3: Elaborative Interrogation

Rated: Moderate utility. Instead of accepting facts at face value, ask yourself "Why is this true?" and "How does this connect to what I already know?" after every key point.

Pressley et al. (1987) found that students who generated explanations for facts remembered 72% of the material, compared to 37% for students who simply read the facts. The "why" question forces your brain to build connections between new information and existing knowledge—creating multiple retrieval paths to the same memory.

How to do it

1. After reading a fact or concept, pause and ask: "Why does this make sense?"
2. Try to answer from your existing knowledge before looking it up.
3. Connect new information to something you already understand. "This is like [X] because..."
4. If you can't generate a "why," that's a signal you need to go deeper on the prerequisite knowledge.

This works especially well for science, history, and any subject with causal relationships. It's less effective for arbitrary facts with no underlying logic (like country capitals)—for those, use practice testing instead.

#4: Self-Explanation

Rated: Moderate utility. As you study, explain each step of a process or solution to yourself. Don't just read a worked example—narrate why each step follows from the previous one.

Chi et al. (1989) found that students who self-explained while studying physics problems solved 82% of new problems correctly, compared to 46% for students who didn't self-explain. The self-explainers weren't smarter—they just forced themselves to process the material deeply instead of skimming.

How to do it

1. When reading a worked example, cover the next step and predict it before looking.
2. Explain to yourself (or out loud) why each step works.
3. When you get confused, that's the most valuable moment—figure out what you're missing.
4. Works especially well for math, programming, and any step-by-step problem solving.

Self-explanation and the Feynman Technique are close relatives. Both force you to articulate understanding rather than just recognizing material—and both expose gaps immediately.

#5: Interleaved Practice

Rated: Moderate utility. Instead of studying one topic at a time (blocking), mix different topics or problem types within a single study session.

Rohrer & Taylor (2007) tested this with math students. One group practiced each problem type in blocks (10 volume problems, then 10 surface area problems). The other group interleaved them randomly. On a delayed test, the interleaved group scored 43% higher. The mixing forced students to identify which strategy applied to each problem—a skill that blocked practice never develops.

How to do it

1. Don't study Chapter 1, then Chapter 2, then Chapter 3 in sequence. Mix problems from all three.
2. When doing practice problems, shuffle different problem types together.
3. Alternate between related subjects in a single study session (30 min biology, 30 min chemistry).
4. It will feel harder and slower. That's the "desirable difficulty" that creates stronger learning.

Read our full guide on interleaving for more research and specific strategies by subject.

What Doesn't Work (and Why Students Keep Doing It)

Three techniques dominate student study habits despite being rated "low utility" by the Dunlosky review:

Rereading

The most common study strategy in the world. Callender & McDaniel (2009) found that rereading a textbook chapter produces minimal improvement beyond the first read. It creates a false sense of familiarity—you recognize the material, which feels like knowing it. But recognition and recall are completely different cognitive processes. On an exam, you need recall.

Highlighting

Highlighting makes you feel productive without doing the cognitive work that creates memories. Dunlosky et al. found no evidence that highlighting improves test performance. Worse, it can hurt learning by making students think they've "captured" the important information, reducing their motivation to process it further.

Summarizing

Better than rereading, but still low utility. The problem: most students write summaries that are too similar to the original text—essentially copying with minor rewording. For summarization to work, you'd need to generate the summary from memory (which is just practice testing with extra steps).

How to Build a Study System That Works

Knowing the techniques isn't enough. You need a system that makes the effective methods your default. Here's a concrete daily workflow:

Before class or reading

• Skim headings and questions to prime your brain (2 minutes)
• Write 3 questions you want the material to answer

During class or reading

• Take brief notes in your own words—not transcriptions
• Ask "why?" after every major concept (elaborative interrogation)
• Mark concepts you can't explain yet—those are your study priorities

After class (same day)

• Close your notes. Write everything you remember on a blank page (practice testing)
• Check your notes and fill in what you missed
• Schedule your next review for tomorrow (distributed practice)

Review sessions (spaced)

• Day 1 after: Quick self-test (5 min)
• Day 3: Self-test + practice problems, interleaved with other topics
• Day 7: Full practice test under exam conditions
• Day 14+: Review only the concepts you got wrong in previous tests

This system looks like more work than rereading. In terms of total hours, it's actually less—because you retain so much more per session, you need fewer total sessions to reach the same level of mastery.

The Research Behind Effective Studying

• Dunlosky et al. (2013) — Evaluated 10 study techniques across hundreds of experiments. Practice testing and distributed practice rated "high utility." Highlighting and rereading rated "low utility." Published in Psychological Science in the Public Interest.
• Roediger & Karpicke (2006) — Demonstrated that one practice test produces greater long-term retention than three additional study sessions. Published in Psychological Science.
• Cepeda et al. (2006) — Meta-analysis of 184 articles: spaced practice improves retention 10-30% versus massed practice. Published in Psychological Bulletin.
• Rohrer & Taylor (2007) — Interleaved math practice produced 43% higher scores on delayed tests versus blocked practice. Published in Instructional Science.
• Chi et al. (1989) — Self-explanation during problem-solving doubled performance on new problems. Published in Cognitive Science.
• Kornell, Hays & Bjork (2009) — Even unsuccessful retrieval attempts improve subsequent learning. Published in Journal of Experimental Psychology: Learning, Memory, and Cognition.

Key Takeaways

• The #1 and #2 most effective study techniques are practice testing and spaced practice—most students rarely use either
• Highlighting and rereading are rated "low utility" by research despite being the most popular study methods
• Effective studying feels harder than ineffective studying—that difficulty is the signal it's working (Bjork's "desirable difficulties")
• You don't need more study time—you need better study methods. The same 2 hours with practice testing produces 2-3x the retention of 2 hours of rereading
• Build a system: self-test the same day, review at increasing intervals, interleave different topics, and ask "why?" constantly

Continue Learning

• Active Recall: The #1 Study Technique
• How Spaced Repetition Works
• The Forgetting Curve Explained
• Interleaving: Why Mixing Practice Beats Repetition
• How to Study for Exams
• The Feynman Technique