How to study effectively

Testing yourself works better than rereading because pulling an answer out of memory makes it easier to pull out again. A study by Roediger and Karpicke (2006) showed it with students and short prose passages, the kind of text you find in a textbook. One group read a passage four times. Another read it once, then wrote down what they remembered three times, without looking back at it.

When the students were tested 5 minutes later, rereading looked better. A week later it had flipped: the tested students recalled 61% of the passage, the rereaders 40%. And the tested group got there with far less reading, about 3.4 times through the passage in all, against about 14.2 for the rereaders.

Rereading also made students more confident they would remember, even though a week later they remembered less. That is the trap: the page feels familiar, so you feel ready. A test tells you what you can actually produce on the day.

How to test yourself

• Close the book and write everything you remember about the topic. Then open it and check.
• Answer flashcards out loud before you flip them. A card you only recognize does not count.
• Do past papers and the questions at the end of chapters, marked, under a time limit.
• Turn each heading of your notes into a question, and answer it without looking.

Spreading study out means coming back to the same material after a gap instead of doing it all in one sitting. It is one of the oldest findings in memory research, and one of the most tested. To see how strong it really is, Cepeda and colleagues (2006) pulled together 839 tests of it from 317 experiments, reported in 184 articles.

Their conclusion was plain: separating study sessions by at least a day, rather than concentrating it all into one session, is extremely useful for remembering in the long run. Every study they examined that tested people more than a month later found that spreading learning across weeks or months beat a gap of a single day.

How far apart the sessions should be depends on how long you need to remember. In a later study, Cepeda and colleagues (2008) taught facts to more than 1,350 people, with gaps of up to 105 days and tests up to 350 days later. For a test a week away, the gap between sessions that worked well was about 20% to 40% of that week. For a test a year away, it fell to about 5% to 10% of the year. The further away the test, the longer the gap can be, though it shrinks as a share of the time left.

For an exam a few weeks out, that means seeing each topic again a day later and again several days after that, then once more in the last week. The calendar below is built that way.

Spacing feels worse while you do it, which is why people skip it. In a study by Kornell (2009), spacing beat cramming for 90% of the participants learning word pairs with flashcards. Yet after the first session, 72% believed cramming had worked better.

The study myth most often repeated is that you learn better when teaching matches your learning style: visual, auditory or hands-on. Some university study guides still tell visual learners to color-code their notes.

The evidence does not back it. Pashler and colleagues (2008) reviewed the research and found no adequate evidence base to justify using learning-styles assessments in education, meaning no good evidence that sorting students by style and teaching to it helps them learn. People do have preferences. What has not been shown is that following them makes you learn more. Let the material decide: a diagram for a process, questions for facts, problems for math.

The second myth is that rereading and highlighting count as real studying. They are certainly what most students do. Of 177 college students asked by Karpicke and colleagues (2009), 84% listed rereading, and 55% called it their main strategy. Only 11% said they tested themselves, and 1% made it their main one.

Rereading and highlighting both landed in the low-utility group of the review above. Its authors said to use other techniques in their place, for example practice testing instead of rereading.

You know your studying is working when two numbers hold for 2 weeks in a row. First, you did at least 80% of the hours you planned. Second, your score on practice questions you have not seen before went up.

Hours come first because no method works in hours you did not study. Most plans are also too big, because people tend to underestimate how long work takes. In a study by Buehler and colleagues (1994), honors students writing a thesis predicted they would finish it in 33.9 days. It took 55.5. Even their worst-case guess, 48.6 days, was short.

Counting real study hours is the part most students skip, and memory is a poor stand-in for it. A week of study feels like more than it was, and the half hour of scrolling inside a two-hour session never makes it into the total.

A good way to track study time should count the hours from what you already write or say about your day. No timers to start and forget. It should keep your planned hours next to your real ones, week by week, so the 80% line is a number you read, not a guess. Most journaling apps stop short of that. They keep how the day felt, which is worth having, but not where the hours went. A week of entries there tells you that studying was stressful, not that it was five hours.

One app built for this is Think in Numbers, a smart journaling app with time tracking built in.

You write or say your day in your own words, as it happens or all at once. The app reads what you wrote and counts the hours that went to each part of it: your study, your phone, and the time you never mentioned (shown as unaccounted). Then it shows those hours over days and weeks. Its targets and weekly plan hold your study hours against your real ones.

Write my first day

Download on the App StoreGet it on Google Play

Or scan with your phone's camera.

For iPhone and Android. Try it on your own day before you pay.

• Test yourself with the book closed, every session.
• Come back to each topic a day later, then several days later.
• Keep the last days for practice tests, not rereading.
• Count the hours you really study, and plan from that number.

Pick your exam date above, and do the first recall tonight.

The research behind this page is listed below, each linked to the paper at its publisher.

1. Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J. and Willingham, D. T. (2013). Improving Students' Learning With Effective Learning Techniques: Promising Directions From Cognitive and Educational Psychology. Psychological Science in the Public Interest, 14(1), 4 to 58.
2. Roediger, H. L. and Karpicke, J. D. (2006). Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention. Psychological Science, 17(3), 249 to 255.
3. Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T. and Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354 to 380.
4. Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T. and Pashler, H. (2008). Spacing Effects in Learning: A Temporal Ridgeline of Optimal Retention. Psychological Science, 19(11), 1095 to 1102.
5. Kornell, N. (2009). Optimising learning using flashcards: Spacing is more effective than cramming. Applied Cognitive Psychology, 23(9), 1297 to 1317.
6. Karpicke, J. D., Butler, A. C. and Roediger, H. L. (2009). Metacognitive strategies in student learning: Do students practise retrieval when they study on their own? Memory, 17(4), 471 to 479.
7. Pashler, H., McDaniel, M., Rohrer, D. and Bjork, R. (2008). Learning Styles: Concepts and Evidence. Psychological Science in the Public Interest, 9(3), 105 to 119.
8. Buehler, R., Griffin, D. and Ross, M. (1994). Exploring the "planning fallacy": Why people underestimate their task completion times. Journal of Personality and Social Psychology, 67(3), 366 to 381.