How to catch up on missed lectures fast (without rewatching everything)

The default catch-up plan — “I'll watch the recording at the weekend” — has terrible economics. A recording costs the full lecture length (more with pauses), can't be skimmed the way text can, and most of its runtime is filler: admin, repetition, tangents, the slow walk through slides you'd understand instantly on paper. The 50 minutes contains maybe 10 minutes of explanation you actually need — and you don't know which 10 minutes until you've watched all 50.

Worse, watching is passive. You can rewatch an entire lecture, feel caught up, and retain almost none of it — the same illusion of competence that makes re-reading feel productive. That's why “I'll rewatch at the weekend” so often becomes three unwatched recordings by week 9.

The slides are the lecture's skeleton — the lecturer chose what went on each one. What's missing is the spoken explanation. So the efficient catch-up is: take the skeleton, add the explanation back in writing, and only touch the recording for the few slides that stay confusing.

1. 01Skim the deck end to end (5 min). Get the shape: what question does this lecture answer, what are its three or four moves? Note which slides look self-explanatory and which look like hieroglyphics.
2. 02Get every slide explained (15–20 min). Work through the deck with plain-English explanations beside each slide — what it means, why it's there, how it connects to the previous one. This is the step that replaces the recording.
3. 03Interrogate the stubborn slides (5–10 min). Ask follow-up questions on anything still fuzzy. If a slide survives written explanation and follow-ups, it earns a targeted trip to the recording — jump straight to that slide's timestamp, watch two minutes, leave.
4. 04Close everything and self-test (5 min). Answer a few questions on the lecture from memory. Pass, and you're caught up in the sense that matters. Fail, and you found out now instead of in the exam hall.

Total: 30–40 minutes per missed lecture, versus 90+ for the rewatch-and-highlight ritual — with a self-test receipt at the end proving it worked.

Borrowed notes feel like the obvious shortcut, but they're a filtered copy: what your coursemate understood, compressed into what they had time to write. The gaps in their understanding become invisible gaps in yours, and anything they found obvious (but you wouldn't) simply isn't there.

Use them for the one thing they capture that slides don't: emphasis. “He spent 20 minutes on this slide”, “she said this comes up every year”, the worked example that was done on the visualiser and never uploaded. Skim borrowed notes for those cues after step 1, then do your own comprehension work on the deck itself.

Falling seriously behind changes the strategy, because lectures usually depend on each other and this week's lecture is happening now. Two rules:

• Serve the present first. Before the next lecture, catch up on its direct prerequisites — often just one or two specific decks — so you stop adding to the pile. A lecture you can follow live is a lecture you never have to catch up on.
• Then clear the backlog in order, fast. Slides-first method, one lecture per sitting, self-test at the end of each. At 30–40 minutes per lecture, four weeks of a typical module is an entirely survivable weekend — not the catastrophe it feels like.

If the backlog collides with exam season, switch to the triage system in our guide to dense content before exams — coverage rules change when the deadline is fixed.