Ace
Short answer: on the same day, close your notes and write down everything you remember from the lecture, then open the slides and fill the gaps in a different colour, then turn the gaps into a handful of questions. Answer those questions again the next day and a few days later. Recalling before you reread is the important part: it shows you what you actually kept, and testing yourself holds up better over days than reading again.
Why does the same day matter?
Forgetting is fastest at the start. In 2015, Murre and Dros repeated Ebbinghaus's classic forgetting experiment, with one person learning lists and relearning them after gaps from 20 minutes to 31 days. Their curve looked much like the original from the 1880s: a steep early drop, then a slower slide. We explain the curve itself in our post on the forgetting curve.
That shape is why university study-skills teams keep giving the same advice. The University of Newcastle (Australia) library tells students to revise their notes "as quickly as possible after the lecture" and to reread them within 24 hours if they can. The University of Arkansas for Medical Sciences student success centre goes further and calls it same-day reinforcement: review a lecture the day you hear it and you prevent forgetting and save time later.
The catch is what "review" means. Most students reread their notes once, nod along and stop. That feels like work, but it mostly tells you what is on the page, not what is in your head. The version below starts with your head.
What does a same-day review look like?
This is the after-lecture reset we use. It takes one sitting, ideally within a few hours of the lecture, and needs only your notes and the lecturer's slides.
- Close everything and recall. On a blank page, write down everything you can remember: the main argument, the key terms, any example the lecturer used, any diagram you can sketch. Do not look at your notes. If you get stuck, write the headings you remember and try to fill each one.
- Open the slides and fill the gaps. Now go through the slides and your notes, and add what you missed in a different colour. The coloured parts are the most useful thing you will produce all day: they are exactly what you did not keep.
- Turn the gaps into questions. For each coloured bit, write a question whose answer is that bit. "What are the three stages of X?" "Why does Y happen when Z?" Keep them short, one fact or idea each.
- Mark what confused you. Anything you still do not understand after reading the slides goes on a separate list for the seminar, the lecturer's office hours or the textbook. Do not try to solve it all tonight.
That is the whole reset. Notice what is missing: no rewriting your notes neatly, no highlighting. If you want a better system for the notes themselves, our guide on how to take lecture notes covers the methods.
Why recall before you reread?
Because recalling is itself a form of studying, and a strong one. In Roediger and Karpicke's 2006 experiments, students read short prose passages and then either read them again or tried to write down what they remembered, without feedback. On a test five minutes later, the rereaders did slightly better. On the delayed tests the pattern flipped. In the first experiment, a week later, the students who had practised recall remembered 56% of the material and the rereaders 42%. The rereaders also felt more confident they would remember it, which is the trap: rereading feels better and works worse.
Karpicke and Blunt (2011) compared recall with a more active-looking method: building a concept map while looking at the text. Students who practised retrieval did better on a test a week later, including on questions that asked them to draw inferences, and even when the final test was to draw a concept map. Making a beautiful summary page is not the same as making your memory do the work.
Recall first also gives you better information. If you reread first, everything looks familiar and you cannot tell what you would have forgotten. If you recall first, the gaps are on the page in a different colour. For more ways to run the recall step, see our list of active recall techniques or try the blurting method, which is a close cousin of step one.
What should you do over the next few days?
The same-day review is the first round, not the last. The questions you wrote are now your plan for the week.
- Next day: answer your questions from memory before looking at anything. Tick the ones you got and keep the ones you missed.
- Two or three days later: answer only the missed ones, plus a few you got right, so you are not just practising the easy ones.
- End of the week: mix that lecture's questions with the previous week's. Mixing lectures is closer to what the exam will do.
Each round should be short. You are not re-studying the lecture; you are checking what has held and patching what has not. If you want the timing worked out in more detail, our spaced repetition schedule lays out the intervals.
What if you have lectures back to back?
Then do the smallest version that still counts. Between lectures, on the bus or in a queue, try to say the three main points of the last lecture to yourself without looking. That is retrieval, and it takes almost no time. In the evening, do steps two and three for each lecture, even briefly: fill the gaps from the slides and write three or four questions per lecture.
If you missed the lecture entirely or you are already several behind, this routine is not the place to start. Our guide on how to catch up on missed lectures deals with the backlog first, and the reset keeps it from growing again.
Writing the questions is the step most people skip. Ace can do that part from the day's slides: upload the PowerPoint or PDF, pick the lecture, and practise questions written only from that file, with the sentence from your slides that backs each answer shown underneath. You still do the recall; Ace gives you something to recall against. See how it works.
Frequently asked questions
How soon after a lecture should I review it?
The same day is best, ideally within a few hours. University study-skills guides commonly say within 24 hours. The earlier you review, the more you have left to recall.
Should I rewrite my lecture notes?
Only if your notes are unreadable. Rewriting is mostly copying. The same time spent recalling and then filling the gaps from the slides tells you far more about what you know.
What if I can barely remember anything when I try to recall?
That is normal after a dense lecture, and it is still useful. Research on unsuccessful retrieval attempts suggests that trying and failing helps you learn what you look up afterwards. Write down headings or single words, then fill in from the slides.
Is listening to the recording again a good review?
It is a form of rereading, so it is slow and passive. Use the recording to fill specific gaps you found during recall, not to sit through the whole lecture again.
Sources
- Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255.
- Karpicke, J. D., & Blunt, J. R. (2011). Retrieval practice produces more learning than elaborative studying with concept mapping. Science, 331(6018), 772–775.
- Murre, J. M. J., & Dros, J. (2015). Replication and analysis of Ebbinghaus' forgetting curve. PLOS ONE, 10(7), e0120644.
- University of Newcastle Library (Australia). Note taking in lectures and tutorials: After the lecture or tutorial. University of Newcastle LibGuides.
- UAMS Educational and Student Success Center. Same day reinforcement. University of Arkansas for Medical Sciences.
