Layer three: write a brief executive summary

For the most important notes, add a two- to three-sentence summary at the top that captures the whole note’s essence.

Why it works

The executive summary is the note’s most compressed layer — it distills the core idea into prose that can be understood in ten seconds. Writing it requires generating an explanation (not just selecting), which is the highest-elaboration form of processing and produces the strongest encoding. The summary also makes the note maximally reusable: a future reader (including your future self) can assess whether the full note is relevant in seconds.

How to do it

1. Apply layer three only to notes that have already received layers one and two and are clearly central to ongoing or recurring work.
2. Write two to three sentences at the top of the note that answer: "What is the main idea here, and why does it matter?"
3. Write for your future self who has forgotten this note entirely — assume no context.
4. Do not rewrite the note; summarize its most essential claim and its key supporting detail.

Evidence

Generative summarization — writing a summary in your own words — is among the most effective learning strategies in educational research, producing better retention than re-reading, highlighting, or passive review. (rct)

The generative processing benefit applies to writing the summary; having a summary in the file without having written it yourself provides no learning benefit.

Sources

• Dunlosky et al. (2013), practice testing and distributed practice significantly outperform many other learning strategies, Psychological Science in the Public Interest

Common mistake

Writing layer-three summaries for every note proactively, rather than only for notes that actually recur and prove their worth over time — a massive time investment with low return on rarely-used material.