Module 5 · Making decisions · Lesson 10 of 10

Pre-mortems and decision journals

Imagine it failed and ask why. Write down what you expected. Then review it once — not forever.

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The idea

A pre-mortem is a simple exercise done before a decision or plan: imagine it is a year from now and things have gone badly. Then ask, “What happened?” Because the failure is imagined as already real, people find it easier to name risks they would otherwise keep to themselves.

A decision journal is a short record written at the time of a decision: what you decided, what you knew, what you expected to happen and why, and how you felt. Later, it lets you judge the decision by its reasoning rather than only by how it turned out — because good decisions sometimes have bad luck, and poor ones sometimes get lucky.

Together they help you revisit decisions without endless second-guessing. Choose in advance when you will review a decision — a date, not “whenever I worry”. On that date, read the journal, ask what you have learned, and either continue or adjust. Between reviews, let the decision stand.

Why it matters

Without a record, memory rewrites the past: we remember having been more certain, or more doubtful, than we were. A written record and a set review date turn decisions into lessons and stop them from becoming a source of constant worry.

See it happen

Noor decides to start a small baking business alongside her job. A month in, sales are slow and she keeps wondering at night whether she made a terrible mistake.

The first read

The slow start seems like strong evidence she chose badly, so she lies awake going over the decision again and again.

With this idea

She had written a decision journal entry: she expected slow sales for three months and set a review date for the end of month four. Reading it calms her — the slow start was expected. She stops re-deciding nightly and reviews properly on the date, when sales are rising.

What changed

A written record and a fixed review date replaced nightly second-guessing.

Easy to get wrong

• Judging a decision only by its outcome. A good decision can turn out badly because of luck, and the reverse.
• Reviewing constantly. A review date protects you from re-making the same decision every day.

Different perspectives

Reasonable people disagree here. None of these is presented as the final word.

Records make you a better decision-maker

Writing down expectations and reasons makes it possible to learn from decisions rather than from memories that shift over time.

Not every decision needs this

Critics note that journaling every choice can become its own kind of overthinking; it earns its place for important, uncertain decisions, not for everyday ones.

What this rests on

Practical wisdom. A widely used way of working. Useful to try — not a scientific law.

• Gary Klein — Sources of Power (1998) and the project premortem (2007) — Research on how experienced people decide under pressure by recognising patterns; and the premortem — imagining a plan has failed and asking why.
• Annie Duke — Thinking in Bets (2018) — A former professional poker player on separating the quality of a decision from the luck of its outcome, and on keeping a record of your reasoning.

Try it: A one-minute pre-mortem

1. Pick a plan or decision you are about to commit to.
2. Imagine it is a year later and it has gone badly. Write three reasons why.
3. For the most likely reason, write one thing you could do now to make it less likely.
4. Write the date you will review the decision.

Reflect

• Which past decision do you keep re-making in your head?
• What did you expect to happen when you made it — as best you can remember?

Use it in the coming days

For your next important decision, write a short decision journal entry — what you expect and why — and put a review date on your schedule.

Where to do it: My Reviews

A review date for a decision belongs with your other reviews, so it actually happens.