T The Useful Margin
Decision Records

How to Keep a Decision Log You Will Reuse

A The Useful Margin guide · Updated 2026-07-19 · 4 min read
How to Keep a Decision Log You Will Reuse
Quick answerKeep a useful decision log by recording the decision date, context, alternatives, choice, reasons, assumptions, expected result, owner, and a review date. Write the choice as a bounded action rather than an aspiration, link to supporting evidence instead of pasting an archive, and name an early warning or stop condition. At review, record the outcome, surprises, assumptions that held, and whether to keep, change, or stop. Judge the reasoning available at the time as well as the result, because luck can reward weak process and uncertainty can punish sound choices.
Contents

Record the decision before hindsight redecorates it

A useful decision log captures what you chose, why, which alternatives you considered, what you expected, and when you will review the result. Keep each entry short enough to complete while the reasoning is fresh. The purpose is not to prove that Past You was brilliant. It is to give Future You an honest record before the outcome starts pretending it was inevitable.

Use a decision log for choices you may revisit, repeat, explain, delegate, or learn from. Do not log every sandwich. Unless lunch has acquired a budget, a committee, and measurable downside, memory may handle it.

Choose one searchable home

Keep the log in a place you already open: a notebook, spreadsheet, notes app, text file, or database. The tool needs reliable search, dates, backup, and access appropriate to the information. Fancy relationships and colorful properties are optional.

Use one consistent title pattern:

YYYY-MM-DD — decision — short subject

Examples include 2026-08-26 — choose — workshop venue or 2026-08-26 — stop — monthly newsletter. An ISO-style date sorts cleanly and removes the international suspense of whether 08/09 means August or September.

Do not place passwords, recovery codes, confidential health information, protected work data, or another person's sensitive details in a casual log. Use an approved secure system for records that require one.

Use a nine-line template

Copy this structure:

Decision:
Date:
Context:
Options considered:
Choice:
Reasons:
Assumptions:
Expected result:
Review date:

Add an owner when the decision belongs to a team, and a link to supporting material when needed. Keep the supporting document separate rather than pasting an entire research archive into the entry. A decision log should point to evidence, not swallow the library.

Make the decision sentence testable

Write the choice as an action with a boundary. “Improve communication” is an aspiration. “Send one project update every Thursday for four weeks, then review replies and missed questions” is a decision.

Include what you are not deciding. A trial of one meeting format does not settle every future meeting. Choosing one vendor for a pilot does not authorize unlimited renewal. Boundaries prevent a small choice from quietly acquiring an empire.

If the decision has money, safety, legal, medical, employment, privacy, or contractual consequences, use the qualified advice and formal approval process the situation requires. A personal log can document professional advice; it cannot replace it.

Preserve alternatives without writing a novel

List the serious options and one sentence on why each was declined. Include “do nothing yet” when delay is genuinely available. You are preserving the decision landscape, not writing a defense brief against imaginary critics.

For each option, record the same few criteria: cost, time, reversibility, risk, effort, fit, or another relevant measure. Define subjective terms. “Simpler” might mean fewer weekly steps, less training, one owner, or no new software; those are different promises wearing the same adjective.

State assumptions and expectations

Assumptions are facts you are acting as though true: the venue can hold the group, the software export contains attachments, the weather permits the route, or the collaborator has two hours available. Mark what has been verified and what remains uncertain.

Then write the expected result in observable language. Use a range or condition when precision would be invented. “Most invited participants can complete registration without staff help” is more honest than a confidence-heavy percentage pulled from the atmosphere.

Name an early warning sign and a stop condition. A reversible decision becomes expensive when nobody agrees what would trigger reversal.

Pick a review date that matches the decision

Review after enough evidence can exist but before the consequence becomes difficult to change. A one-week process trial may need review next Friday; a seasonal choice may need the end of the season. Avoid “someday,” a date with an excellent record of nonattendance.

Put the review in the same system that surfaces other commitments. Link the log entry. During a weekly notes review, check whether any decision has reached its review point or lost an owner.

Review the reasoning, not only the outcome

At review, add:

Outcome:
What surprised us:
Which assumptions held:
Keep, change, or stop:
Next review:

A good outcome can follow weak reasoning or luck. A poor outcome can follow a sensible choice under uncertainty. Ask whether the information, criteria, and process were reasonable at the time—not whether the result made you look clever afterward.

Browse decision records for more templates. Over time, look for repeated assumptions, delays, blind spots, and successful small tests. The log becomes valuable when it changes the next decision, not when it grows large enough to frighten the search bar.

FAQ

What decisions belong in a decision log?

Log choices you may repeat, revisit, explain, delegate, audit, or learn from—especially when alternatives, assumptions, money, time, risk, or several people are involved. Skip trivial choices unless a pattern matters. High-stakes legal, medical, financial, safety, employment, privacy, or contractual decisions still require qualified advice and formal procedures; the log records reasoning and sources but does not replace professional judgment or authorization.

How long should a decision-log entry be?

Use the shortest entry that preserves the choice, context, credible alternatives, reasons, assumptions, expected result, owner, and review date. Many ordinary entries can fit in several lines; complex decisions may link to separate analysis. If completing the log becomes burdensome, reduce prose before removing the review date or assumptions. A decision record must be easy enough to write while the reasoning is still fresh.

What is the difference between a decision log and journal?

A decision log is structured around a choice and later review, while a journal may capture broader experience, feelings, events, or reflection. They can coexist or share a tool. The log benefits from consistent fields and searchable dates; the journal can remain more open. Do not force sensitive personal reflection into a shared decision system merely because the two formats overlap.

When should I review a decision?

Review after enough evidence can exist but before the consequences become unnecessarily difficult to change. Match the date to the decision: a short process trial may need days or weeks, while a seasonal choice needs a full cycle. Add an earlier warning or stop condition for safety, cost, or performance. Put the review in a calendar or task system that will surface it reliably.

How do I avoid hindsight bias in a decision log?

Write assumptions, uncertainty, rejected options, and expected outcomes before results arrive. Preserve the information sources and dates available at the time. During review, separate process quality from outcome quality: luck can rescue weak reasoning, and a reasonable choice can fail under uncertainty. Ask which signal was missed, which assumption changed, and what rule should influence the next similar decision without pretending the result was obvious.