In an online course, the temptation to write everything down is strong. Nothing is rushing you: you can pause the video, rewind, listen to a sentence again, and the transcript is often right there below the video. So you fill page after page, with the reassuring feeling that you are working seriously.
The result, however, is often disappointing. You hardly ever read those pages again. And when you do, a few weeks later, you realise how little you have retained. The time spent copying gave the impression of learning, without much learning actually happening.
There is a way of taking notes that is both shorter and far more effective. It rests on two of the most robust findings in the psychology of memory.
What the research says
The first finding is called the testing effect. It shows that trying to recall information from memory makes you remember it better than rereading it. In a now-famous experiment, Henry Roediger and Jeffrey Karpicke asked students to study a text, then either reread it or test themselves on it. A week later, those who had tested themselves remembered it much better. A striking detail: they were nonetheless convinced they had learned less than the others (Roediger and Karpicke, 2006). Rereading gives a feeling of mastery; testing actually builds memory.
The second finding is called the spacing effect. Spreading your reviews over time makes you remember better than cramming them all at once. A large review published by Nicholas Cepeda and colleagues in 2006 confirmed it across hundreds of experiments (Cepeda et al., 2006).
The practical consequence of these two findings is simple, and it changes everything: your notes should first and foremost help you test yourself later, not copy the course.
During the video: almost nothing
Watch the video writing as little as possible. Just note down new words, the exact formulas or commands you will need again, and the passages you don’t understand, with the video timestamp so you can go back.
Why so little? Because taking full notes during the video splits your attention between listening and writing. And because you almost always end up writing what the teacher says, rather than what you yourself understand.
Straight afterwards: write from memory
This is the heart of the method. As soon as the video ends, close it, and take five minutes to write, from memory, the two or three main ideas, in your own words. Add an example: the course’s, or better still, one you invent. Finally, note what still feels unclear.
Only then compare with the video or transcript, and fill in what is missing. The exercise seems modest, but it is already a test, in Roediger and Karpicke’s sense. On its own, it does a good part of the memorising.
Questions rather than summaries
A summary gets reread; a question gets worked on. So get into the habit of turning every important note into a question you can answer later.
Instead of writing “the median is more robust to extreme values than the mean”, write: “why prefer the median to the mean to describe salaries?” Instead of “GROUP BY groups rows”, write: “write the SQL query that gives the number of orders per customer”. When the time comes, the question will force you to rebuild the answer, and that is precisely what makes it stick.
About ten questions per course week is plenty. Write the answer on the back of the card, or on the line below, hidden.
Review your questions, spaced out
At the start of each session, take a few questions from earlier sessions and answer them from memory before checking. A simple rhythm works very well: a few questions from the previous session, a few from a week ago, a few from a month ago.
If you would rather automate this, a spaced-repetition flashcard app such as Anki, which is free, works out when to ask you each question again, based on your previous answers.
Paper or laptop?
It is a question that comes up often. A study published in 2014 suggested that handwritten notes led to better recall than laptop notes, because they forced people to rephrase. The finding made a big splash, but later attempts to replicate it did not find a clear effect.
What really matters, then, is not the tool. It is rephrasing rather than copying, and testing yourself afterwards. In practice, paper is often handier for maths and diagrams, and a laptop for code, which you will need to run anyway.
A simple, one-page format
For each course week, one page is enough, organised like this:
| Part | Content |
|---|---|
| Top | The course, the week, the date |
| Key ideas | Three to five ideas, in your own words |
| Example | One worked example, preferably your own |
| Questions | Five to ten questions, answers hidden |
| Unclear | What is left to clear up, and where to look |
This format fits on one page, can be reread in two minutes and feeds directly into your reviews. It is far less work than copying out a course, for an incomparably better result.
In short
During the video, note only new words, formulas and sticking points. Straight afterwards, write for five minutes from memory, then check. Turn your notes into questions rather than summaries. And come back to them at the start of each session, spacing out your reviews.
This method fits naturally into a ten-hour week, as we explain in studying 10 hours a week for a year.