Attribution is verified; cases are not independent causal proof. Cohort comparisons can be confounded, and a transaction price is not lifetime contribution.
Core method and failure of weak purchase proxies, read alongside full book.
Ries proposes testing critical business assumptions with minimum viable products, establishing baseline behavior and evaluating experiments before deciding whether to continue or change strategy. A smoke test establishes interest only; Votizen's letters of intent did not become sales. Academy adaptation: separate interest, payment, learning and contribution, and predefine a decision rule.
146
99
Measure; Pivot (or Persevere), supplied PDF sheets
Paraphrase checked against supplied sheets 99–146, with charts/tables visually inspected. Verification concerns source attribution and coverage, not universal truth.
Provenance
Private paraphrase; source-grounded propositions and Academy inference are distinguished. The linked Literature Note provides whole-book coverage and critical qualifications.