“A summary that's just your notes with some sentences removed is still your notes. It hasn't done the actual work.”
Most "summaries" I made in my first year were just my lecture notes with the font size turned down and a few sentences deleted. Same order, same detail, same forty minutes to read through again the week before an exam.
That's not a summary. It's a slightly shorter copy of the same document, doing the same job the original already did, just less well because now some of the detail's missing too.
A summary has a different job than notes
Notes exist to capture what happened in the lecture, roughly in the order it happened, so you have something to refer back to. That's their whole purpose, and they're fine at it.
A summary exists to answer a completely different question: if you only had fifteen minutes before this topic came up again, what would you actually need to have front of mind? That's not "everything, but shorter." It's a much smaller list, organised by importance rather than by the order the lecturer happened to say things in.
Confusing the two is why so many summaries end up exactly as long and exactly as hard to review as the original notes were.
Structure by importance, not by chronology
A lecture is delivered in whatever order made sense to explain it live. A summary doesn't have to respect that order, and usually shouldn't. Group by:
- The core idea. One or two sentences. If someone asked "what was this lecture actually about," this is the answer.
- The concepts that build on it, in the order that makes them easiest to understand, not the order they were said in.
- The specific facts, dates, formulas or terms you'll actually be examined on, listed plainly rather than buried in paragraphs.
- The bit that confused you. This deserves its own line, flagged clearly, because it's the part most likely to need a second look later and most likely to get lost in a wall of otherwise-fine notes.
That last one matters more than people give it credit for. A good summary doesn't pretend every part of the lecture was equally clear. It tells future you exactly where to spend the extra five minutes.
Cut anything you'd recognise instantly
A genuinely useful test for whether a line belongs in a summary: if you saw just this sentence with no other context, would you immediately know what it means, or would you need the surrounding explanation to make sense of it again?
If it's instantly clear, it survives the cut. If it needs the paragraph around it to land, it either needs to be rewritten as something that stands alone, or it belongs in the full notes and not the summary. This is usually where a summary shrinks the most: definitions and examples you'll recognise the instant you see them again don't need to be spelled out in full.
Rewrite it, don't copy it
The other reason cutting sentences from your notes doesn't produce a real summary is that you skip the part that actually helps you learn: putting it in your own words. Copying is nearly effortless, which means very little of it sticks. Rewriting forces you to actually process what the lecture said well enough to say it differently, which is most of the value of making a summary in the first place, separate from having a document to reread later.
Flag the difficult bits honestly
It's tempting to write a summary that makes everything sound equally solid, because admitting "I don't fully get this part" feels like a failure. It's the opposite. A summary that flags its own weak points is more useful than one that hides them, because it tells you exactly where to spend your remaining study time instead of spreading it evenly across material you already knew.
Where this gets slow
The actual bottleneck with summarising is the same one as with flashcards: doing the mental work of finding the core idea and cutting the rest takes real time, and forty slides of dense material is a lot to work through by hand every single week of term.
This is what our AI summary generator is built to speed up. It reads your uploaded slides and drafts a summary organised exactly this way: the core idea, the concepts, the specific facts, and the parts flagged as genuinely difficult rather than everything presented as equally important. You still read it, correct anything it got wrong, and add your own notes, but the first pass that used to take an hour takes a few minutes.
The short version
A real summary isn't your notes with some lines removed, it's a rewritten, reordered document built around what actually matters and what you actually struggled with. Structure by importance, cut what you'd recognise instantly, rewrite instead of copy, and flag the hard parts honestly rather than smoothing them over.