Externalize decisions not just information

The idea

The most valuable thing to capture is why you chose what you chose. Decisions decay faster than facts — and unlike facts, they cannot be reconstructed after the outcome is known.

Three weeks ago you made a decision. Maybe you picked a technology, declined a meeting, restructured a project, or changed your morning routine. You remember what you chose. You might even remember what happened next.

But ask yourself: what alternatives did you seriously consider? What information did you have at the time — and what were you missing? What were you optimizing for? What trade-offs did you consciously accept?

An example

A team lead chooses PostgreSQL over DynamoDB for a new service. Six months later, the service struggles under write-heavy load. Everyone says 'obviously we should have used DynamoDB.' But the original decision was made because the team had zero DynamoDB experience, the deadline was eight weeks out, and the data model was deeply relational. Without a written record of those constraints, the team learns nothing — they just blame the decision-maker. With a decision log, they can ask the right question: 'Given what we knew then, was the process sound? What new information would change the answer?'

Where it goes wrong

Documenting only the conclusion without the context. Writing 'We chose React' tells future-you nothing. Writing 'We chose React because the team already knows it, the timeline was six weeks, and we valued shipping speed over long-term performance' tells future-you everything. The decision without the rationale is a fact. The decision with the rationale is a learning object.

Make it stick

Create a decision log — a single document, notebook page, or folder where you record decisions as you make them. Start with one entry today. Use the five-line format from the exercise. The habit matters more than the format. After one week, review your entries and notice which decisions you would have already misremembered without the record.