Why Rereading Your Notes Is a Waste of Time
# Why Rereading Your Notes Is a Waste of Time
You have an exam coming up. You pull out your notes, read through them carefully, and feel a growing sense of confidence. By the third pass, everything looks familiar. You recognize the terminology, follow the explanations, and feel like you know the material. Then you sit down for the test and draw a blank.
This is not a rare experience. It is the predictable result of using rereading as a primary study strategy. And despite being the most popular study method among students, rereading is one of the least effective ways to build durable knowledge.
The Research Is Clear
The most comprehensive review of study strategies was published by Dunlosky, Rawson, Marsh, Nathan, and Willingham in 2013. They evaluated ten common learning techniques based on decades of experimental research. Rereading received a rating of "low utility" - meaning the evidence showed it produced minimal learning gains relative to the time invested.
This was not a close call. Across multiple studies, multiple subject areas, and multiple types of assessments, rereading consistently underperformed active strategies like practice testing and distributed practice, both of which received "high utility" ratings.
Karpicke and Blunt (2011), in a study published in Science, directly compared rereading with retrieval practice. Students who read a passage once and then practiced recalling it significantly outperformed students who read the same passage four times - even though the rereading group spent more total time with the material.
Four readings. More total time. Worse results. That is how ineffective rereading is.
Why Rereading Feels Like It Works
If rereading is so ineffective, why does it remain so popular? Because it creates a powerful cognitive illusion.
The Fluency Illusion
When you read something for the second or third time, it feels easier. The sentences flow smoothly. You recognize the vocabulary. Your brain processes the text quickly and without effort. This processing fluency feels like understanding. It feels like you have learned the material.
But fluency and mastery are different things. Fluency means you can recognize information when you see it. Mastery means you can produce it from memory when prompted. Exams test production, not recognition. The gap between these two abilities is where rereading fails.
Kornell and Bjork (2008) demonstrated this in a series of experiments showing that students consistently predicted they had learned more after rereading than they actually had. The fluency created by repetition directly inflated their confidence without proportionally increasing their actual knowledge.
Familiarity vs. Understanding
There is a crucial difference between "I have seen this before" and "I understand this well enough to explain it." Rereading produces familiarity. It does not produce understanding. You can reread a passage about the Krebs cycle twenty times and still be unable to explain how it works or answer a question that requires applying the concept in a novel way.
Understanding requires active processing - connecting ideas, generating explanations, solving problems. Rereading is passive. Your eyes move across the page, but your brain is not doing the kind of work that builds deep comprehension.
What Rereading Actually Does to Your Brain
When you read something for the first time, your brain is actively constructing meaning. You are decoding new information, connecting it to prior knowledge, and building a mental representation of the content.
When you reread, much of that constructive work is already done. Your brain recognizes the text and takes shortcuts. It skims rather than processes. It retrieves the feeling of familiarity rather than rebuilding understanding from scratch. This is why rereading takes less effort than initial reading - and why it produces less learning.
Neuroscience research on repetition suppression shows that repeated exposure to the same stimulus actually reduces neural response over time. Your brain literally pays less attention to things it has seen before. This is an efficient adaptation for everyday life but a terrible mechanism for learning.
What to Do Instead
Retrieval Practice
Instead of reading your notes again, close them and try to recall the material from memory. Write down everything you remember about a topic. Then open your notes and check what you got right, what you got wrong, and what you missed entirely.
This process - known as retrieval practice or the testing effect - is one of the most well-supported findings in cognitive science. Roediger and Karpicke (2006) showed that a single practice retrieval session produced better long-term retention than three additional study sessions spent rereading.
The effort of pulling information from memory strengthens the neural pathways that store it. Rereading does not require this effort, which is precisely why it does not produce the same strengthening.
Elaboration
After reading your notes once, do something active with the information. Explain it in your own words. Generate examples. Connect it to other concepts. Ask yourself why it is true and how it relates to things you already know.
This elaborative processing forces your brain to engage with the material at a deeper level than recognition. It builds connections between new information and existing knowledge, creating a richer and more retrievable memory representation.
Self-Testing
Create questions based on your notes and quiz yourself. Even simple flashcards force you to produce answers rather than recognize them. The act of generating an answer - even an incorrect one - creates a stronger memory trace than passive review.
If you get a question wrong during self-testing, that is not a failure. Research by Kornell, Hays, and Bjork (2009) showed that incorrect guesses followed by corrective feedback actually enhanced learning more than simply studying the correct answer. The error creates a productive struggle that deepens processing.
Spaced Practice
If you must review your notes, at least space the reviews out over time rather than rereading them repeatedly in one sitting. Cepeda et al. (2006) demonstrated that distributed practice - spreading study sessions across days or weeks - produces substantially better retention than massed practice, regardless of the specific study technique used.
The Time Argument
Some students defend rereading by saying they do not have time for more active strategies. This gets the argument backwards. Rereading is the bigger time investment because you need to do it many times for minimal results. Active strategies like retrieval practice produce better outcomes in less total time.
A 30-minute session of closed-book recall followed by a review of what you missed will produce better retention than two hours of rereading the same notes. If you are short on time, you especially cannot afford to waste it on passive review.
How to Break the Habit
Rereading is the default study behavior for a reason - it is comfortable, easy, and creates a reassuring sense of progress. Breaking the habit requires replacing it with something specific, not just deciding to "study better."
Try this: for your next study session, read your notes once. Then close them completely. Set a timer for ten minutes and write down everything you can remember. Check your notes afterward. Focus your remaining study time on the material you could not recall.
That single change - replacing the second reading with a recall attempt - will produce noticeably better results on your next test. Once you experience the difference, rereading will start to feel like what it is: a comfortable waste of time.