A two-page brief states the problem, names the segment that has it, asserts a large and fast-growing market, says there is nothing else like it, and closes with an engineering estimate. Judged against Cagan's opportunity assessment, what is the honest state of it?

The principle — auditing a proposal means walking a fixed list and marking each item answered, asserted or absent, which is a different exercise from judging whether the writing is persuasive.

Why the key is correct — take the six in order. Exactly what problem will this solve? (value proposition) is answered: the brief states it. For whom do we solve that problem? (target market) is answered: the segment is named. How big is the opportunity? (market size) is asserted — large and fast-growing is a claim with no working behind it, and the assessment does not supply a method that would turn it into an answer. What alternatives are out there? (competitive landscape) is asserted and probably wrong, since nothing else like it almost always means the workaround has not been looked for. Why now? (market window) is absent: the brief never says what has changed. How will we measure success/make money from this product? (metrics/revenue strategy) is absent: an engineering estimate is a cost, not a measure of success. Two answered, two asserted, two missing. The Scrum Guide points the same way about who owns this: The Product Owner is accountable for maximizing the value of the product resulting from the work of the Scrum Team.

Why the others are wrong — calling it complete counts confident prose as coverage and admits a cost estimate as though it were on the list. Reading a large market as an open window collapses two questions that are separate because a market can be large for years before anything makes this the moment. And naming only the measures as missing understates it by three, and defers the one it names until after the decision.

Remember this — walk the list and mark each question answered, asserted or absent; the asserted ones are where briefs go wrong.

Sources — Marty Cagan on assessing product opportunities, Silicon Valley Product Group; the 2020 Scrum Guide.