What is note-taking layers of summarization?

Note-taking layers of summarization is a concept in personal epistemology: Highlight the key points then summarize the highlights — each pass concentrates the value.

Example: You save an article on organizational decision-making to your notes app. On the first read, you bold the sentences that strike you as most important — maybe eight out of sixty. Three weeks later, you are preparing a presentation on how your team makes decisions. You reopen the note and scan the bolded passages. Two of the eight are directly relevant. You highlight those two in a different color. You also write a three-sentence executive summary at the top: 'Organizational decision speed depends on two variables: the reversibility of the decision and the cost of delay. Reversible decisions should be made by the nearest person to the information. Irreversible decisions justify committee deliberation.' That summary did not exist in the original article — it is your compression of the pieces that matter for your specific purpose. A month later, when a colleague asks you how to think about decision authority, you open the note, read the three-sentence summary in five seconds, and give a clear, precise answer. You have distilled a 3,000-word article into three sentences across three separate encounters — and each encounter took less time because the previous pass had already done part of the work.

This concept is part of Phase 43 (Information Processing) in the How to Think curriculum, which builds the epistemic infrastructure for information processing.