Run a milestone

Writing measurable acceptance criteria

Turn vague scope language into outcomes that an agency and client can review consistently.

Anyone preparing a milestone9 min readUpdated July 24, 2026
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Use the ACT test

TestQuestionGood signal
AtomicDoes the criterion describe one outcome?One pass or fail decision
ConcreteCan a client recognize the expected result?Named page, action, value, or state
TraceableCan it be tied to exact agreed language?A precise SOW quote or approved amendment

A useful criterion formula

Criterion formula
On [approved environment or page], when [authorized action or condition occurs], the product must [observable outcome] within/at [measurable threshold], as required by “[exact source quote].”

Rewrite vague promises

VagueMore measurable
The website will be responsive.At 390 px viewport width, the approved pages have no horizontal overflow and the primary navigation remains operable.
The form should work.Submitting valid name, business email, and message values creates the agreed success response without a client-visible error.
The site will be fast.The agreed landing page meets the named performance threshold using the stated tool, device profile, and test conditions.
SEO will be implemented.Each named indexable page has one unique title, one meta description, one H1, and the approved canonical URL.
The design will match the mockup.The named components, content hierarchy, colors, type styles, and states match the approved design revision at the agreed viewports.
The site will be accessible.The named pages and journeys pass the listed keyboard, labeling, focus, contrast, and automated checks in the agreed review scope.

Choose the right evidence

ClaimBest evidence
Visible content or layoutScreenshot plus page URL and viewport
Navigation behaviorRecorded browser action and final URL/state
Form submissionBrowser action plus observed network and success state
Client preference or subjective qualityExplicit client review decision
External business outcomeAuthorized system record outside Greenlit
Compliance or certificationQualified assessment, not a generic browser check

Final review questions

  • Would two reasonable reviewers interpret the criterion the same way?
  • Is the environment, page, action, threshold, or expected state named?
  • Does the source quote actually support the criterion?
  • Can Greenlit collect the required evidence safely and without unapproved side effects?
  • Is a human client decision more appropriate than automation?
  • Would changing this criterion after work is finished alter the agreed scope?