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Clear Decisions

How to Write a One-Page Decision Memo

Try Something Small · Updated 2026-07-19 · 4 min read
How to Write a One-Page Decision Memo
In briefWrite a one-page decision memo by stating the choice and deadline, summarizing the current situation, and listing two to four genuine options, including no change when feasible. Compare each option's main benefit, cost, and uncertainty against three to five defined criteria. Separate known facts from assumptions and unknowns, then recommend one option and state the strongest objection fairly. Finish with what would change your mind, whether the choice is reversible, and a named next action with an owner and date.
Contents

Give the decision one sentence

A one-page decision memo is a compact record of a choice, the reasons behind it, and the next action. It is useful when a decision matters enough to think through but not enough to establish a parliamentary inquiry. You might use one for choosing software, changing a weekly schedule, booking a course, or deciding whether to repair or replace an everyday item.

Begin with: I need to decide whether to ___ by ___.

Name the deadline because an unbounded decision can quietly become a hobby. If the date is externally fixed, record it. If not, pick a reasonable review point based on the cost of delay and the information still available.

For high-stakes medical, legal, safety, or financial choices, a memo may organize questions; it does not replace qualified advice.

State the current situation

Use three or four sentences. Explain what prompted the choice, what happens if you do nothing, and which constraints are real. Distinguish a requirement from a preference:

That last label matters. Assumptions love dressing as facts and strolling past reception. Marking them makes them available for checking.

If you could learn through a reversible trial first, use a two-week personal experiment rather than arguing with yourself in increasingly formal fonts.

List genuine options, including no change

Write two to four feasible options. Include “do nothing for now” when it is genuinely available, along with its consequences. Do not pad the list with choices you would never accept simply to make the favorite look athletic.

For each option, note the main benefit, main cost, and largest uncertainty. Use ranges when cost or time is uncertain, and say where an estimate came from. If you have not checked a number, label it an estimate rather than giving it a necktie and sending it out as fact.

A small table is enough:

Option Main benefit Main cost Largest uncertainty
Keep current setup No transition Existing frustration continues Whether the problem will worsen
Modify it Lower commitment Time and parts Whether the fix addresses the cause
Replace it Potentially solves more issues Higher cost and setup Actual improvement in daily use

The table does not decide. It stops tradeoffs from hiding in separate paragraphs.

Choose three to five criteria

Good criteria reflect the purpose of the decision: reliability, total cost, learning value, time, reversibility, accessibility, or effect on other people. Define what each means here. “Affordable” might mean within an already-set budget, not merely cheaper than the option currently glowing on your screen.

Rank criteria as essential, important, or nice to have. A numerical score can help expose differences, but it should not manufacture precision. If you assign weights, make sure they total 100 percent and explain them. A 73.4 does not become objective because it owns a decimal point.

The tools in clear decisions are built around explicit criteria rather than confidence theater.

Separate evidence, assumptions, and unknowns

Create three short lists:

Then ask which unknown could realistically reverse the decision. Check that one first. More information has value only if it can change the choice or reduce a meaningful risk. Reading a fourteenth comparison page because the buttons have slightly different corners is not diligence. It is tourism.

For claims from vendors or advocates, look for the underlying terms, limitations, and evidence. Record the date, since features, availability, and policies can change.

Write the recommendation and strongest objection

Use this form: I recommend option A because it best satisfies criteria B and C within constraint D. Follow it with the strongest case against your recommendation. If you cannot state that objection fairly, you may be defending a favorite instead of deciding.

Name what would change your mind. This creates a review trigger: a cost exceeds the budget, a required feature disappears, or a trial fails. Reversibility matters too. A hard-to-undo choice deserves more checking than one you can change next Tuesday without summoning three contractors.

Finish with an owner and next action

End the page with who will do what by when. If only you are involved, write it anyway: “I will request two written quotes by Friday” is a next action; “research more” is a fog bank.

Store the memo where you can find it. Review it after the outcome becomes visible and note which assumptions held. That is how a decision becomes feedback rather than folklore. Explore small experiments when the next uncertainty can be tested cheaply before commitment.

One page is a discipline, not sacred geometry. The memo succeeds when another reasonable person—or future you, who is technically a stranger with your passwords—can understand the choice and its logic.

FAQ

When should I use a decision memo?

Use one when a choice has meaningful tradeoffs, several plausible options, or assumptions worth recording, but does not require a long report. Everyday examples include selecting software, changing a schedule, booking training, or repairing versus replacing an item. For medical, legal, safety, or major financial decisions, the memo can organize questions and evidence but should not replace qualified professional advice.

How many options belong in a decision memo?

Two to four feasible options are usually enough for a compact memo. Include waiting or making no change when it is genuinely possible, along with the consequences. Do not add options you would never accept merely to make a preferred choice look better. If the list is much longer, group similar choices first or use the memo to decide which small subset deserves detailed comparison.

Should I score options with numbers?

Scoring can make criteria and tradeoffs visible, but it does not make subjective judgments objective. Define each criterion, explain any weights, and ensure percentage weights total 100 percent. Avoid false precision: a tiny numerical difference may reflect uncertain assumptions rather than a meaningful advantage. Always read the reasons behind the scores and test whether changing a reasonable weight would reverse the recommendation.

What is the difference between a fact and an assumption?

A fact in the memo should be supported by a reliable record, written term, direct observation, quote, test, or other identifiable evidence. An assumption is a plausible belief not yet verified, such as expected setup time. An unknown is information unavailable or not worth obtaining. Labeling all three prevents an estimate from quietly becoming a promise and shows which unanswered question could change the decision.

What should the final recommendation include?

Name the recommended option, the criteria it best satisfies, and the constraint it respects. State the strongest objection fairly and identify new evidence or changed conditions that would reverse the decision. Note whether the choice is easy to undo. Finish with a concrete next action, owner, and date. “Research more” is too vague; “request two written quotes by Friday” can actually be completed.