November 2026 Summaries

Product and marketing teams often test different parts of the same customer journey in separate tools and against separate metrics, which can create conflicting incentives, inconsistent messaging between acquisition and onboarding, slower pages from client-side testing, and occasionally overlapping experiments that confuse users. The text argues that teams should share an experimentation platform, metric definitions, user assignment, guardrails, and visibility into live and completed tests so they can evaluate effects across signups, activation, engagement, retention, revenue, page speed, and errors. Although direct interactions between A/B tests are generally rare, mutually exclusive assignment is recommended for experiments that modify the same experience or make contradictory offers, while most tests can overlap to preserve statistical power. Recommended practices include maintaining a shared experiment calendar, agreeing on success criteria and acceptable tradeoffs before launch, using holdout groups to measure cumulative impact rather than summing individual winners, and reviewing no-code or AI-generated tests for targeting, rendering, analytics, and conflicts. The Philadelphia Inquirer is presented as an example of a cross-functional program that centralized nearly 100 experiments and reported business benefits, including an 11.8% increase in subscriptions from a subscription-offer-page test. GrowthBook is described as an open-source, warehouse-native platform intended to support this approach through shared SQL-defined metrics, consistent assignment, experiment namespaces, holdouts, visual and AI-assisted testing, reporting, and collaboration alerts.