Is rereading my notes a good way to study?

Why rereading feels so effective

When you read a page for the second time, the words come easily and the argument seems obvious. That ease is real, but it describes how smoothly the text is being processed on the page in front of you, and it says little about whether you could produce the same ideas with the page closed. The two can come apart, and a learner who judges progress by fluency may stop studying a topic long before the knowledge is secure.

Rereading is also very common among students. Jeffrey Karpicke, Andrew Butler and Henry Roediger surveyed undergraduates in 2009 about how they study alone, and rereading notes or textbooks was the strategy students reported most often, while testing themselves was reported far less. Their paper describes a student population at one institution, so it shows what those students said they did and cannot establish what every learner does. It does explain why the method deserves a careful look: it is the default for many people.

What the research says about rereading and self-testing

In 2013 John Dunlosky and colleagues reviewed ten widely used study techniques in Psychological Science in the Public Interest. For each one they judged how much evidence supported its usefulness across different learners, materials and ways of measuring results. Practice testing and distributed practice earned the highest rating. Rereading, highlighting and summarising earned the lowest, mainly because the evidence for them was thin or showed gains that were small, narrow or short-lived. These are reviewers' ratings on a three-level scale, so they rank the techniques without giving a measured size of benefit.

The strongest single piece of supporting evidence for self-testing is an experiment by Henry Roediger and Jeffrey Karpicke in 2006, in which students studied short prose passages and then either read a passage again or tried to recall it. On a test five minutes later the students who had reread did better. When the test came a week later the pattern reversed, and the students who had practised recall remembered more. The reversal is the useful part, because it shows that the method that looks better at the end of a study session can be the weaker one when the memory is needed later.

A later meta-analysis by Christopher Rowland in 2014 pooled 61 articles on the testing effect and found an average benefit of roughly half a standard deviation over restudying. That is a moderate effect on average, and individual studies varied. Most of the work used laboratory materials such as word lists and short texts, so how well it carries over to a semester of complex coursework is an open question, though the direction of the result has held across many settings.

Why retrieval strengthens memory when rereading does not

One explanation is that pulling an idea out of memory is a different act from recognising it on a page. Recognition asks whether the idea looks familiar, and recall asks you to rebuild it from your own resources. Rebuilding exposes the places where your understanding is thin, which gives you something specific to fix. Reading again tends to skip that discovery, because every sentence is in front of you as a prompt.

This account is an interpretation of the findings and researchers still debate the mechanism, so treat it as a reasonable working explanation instead of a settled fact. What the experiments support is narrower: on delayed tests, retrieval practice usually produced better recall than restudying the same material for the same time.

Retrieval is not a replacement for ever looking at the material. You need to read something once before you can recall it, and checking your answer against the source afterwards is part of the method, since an unchecked recall attempt can fix a wrong version in place. Dunlosky and colleagues found that retrieval worked best when feedback followed, particularly for harder material.

How to swap rereading for retrieval in your own study

After reading a section once, close the book and write everything you can remember on a blank page. Use your own words and do not worry about the order. Then open the notes and mark what you missed or got wrong in a different colour. The marked gaps become your next study target, and a second attempt a few days later shows whether they have closed. Spacing those attempts matters too, and the post on how far apart to space reviews covers that question.

If writing a full summary is too slow, turn headings into questions and answer each aloud before looking. A question such as "what are the two causes of this effect and how do they differ" forces a specific retrieval, while a heading read silently invites only recognition. Questions that ask you to explain a reason or apply a rule to a new case tend to reveal more than questions that ask for a definition, because a remembered definition can hide a weak grasp of how to use it.

The cost is that retrieval feels harder and your first attempts will be worse than a smooth reread suggested. Struggling to recall is the expected experience and does not show the method is failing. A fair check of your own progress is to test yourself on unfamiliar questions a week later and compare the result with the topics you only reread. That comparison covers a handful of topics and one learner, so it is a prompt for adjusting your routine and falls short of evidence about the method.