Build a metric tree for App Store after a major redesign at global scale

Problem Statement Description

Product context: Apple is a consumer hardware, software, and services company; its products include iPhone, iPad, Mac, Apple Watch, AirPods, iOS, App Store, iCloud, Apple Music, and Apple TV+. App Store is Apple's app marketplace; its products include app discovery, downloads, purchases, subscriptions, reviews, developer distribution, and payment flows.

Apple has rolled out a major global redesign of the App Store across iPhone, iPad, and other relevant surfaces. The redesign may affect how customers discover apps, evaluate quality, install or purchase, subscribe, and return to the store, while also changing how developers and creators gain visibility, acquire users, and monetize.

Your task is to build a metric tree that helps Apple understand whether the redesign is succeeding at global scale. The metric system should connect high-level App Store outcomes to the underlying customer and developer behaviors that drive them, while reflecting Apple’s expectations around premium user experience, privacy, trust, accessibility, and ecosystem health.

This is a metrics interview question. Focus on defining a clear north-star or top-level outcome, decomposing it into measurable input and output metrics, specifying denominators and cohorts, and explaining how the tree would be used to diagnose performance after launch. Do not assume that revenue alone captures success; consider discovery quality, conversion, engagement, creator success, customer trust, and long-term ecosystem retention.

The experience should consider:

- Core customer journeys: browsing, search, editorial discovery, app detail evaluation, install, purchase, subscription, update, and re-engagement.

- Creator and developer outcomes: impressions, qualified traffic, conversion, monetization, retention, and fairness of visibility across app categories and regions.

- Metric definitions with clear numerators, denominators, time windows, and whether they are user-level, session-level, app-level, or market-level.

- Global cohorts such as country, language, device type, OS version, new vs. existing users, paid vs. free apps, subscription apps, and developer size.

- Instrumentation needs across redesigned surfaces, including exposure logging, funnel events, attribution, ranking/editorial placements, and post-install behavior.

- Guardrails for privacy, trust, accessibility, app quality, refunds, crashes, misleading content, parental controls, and user complaints.

- Decision usefulness: how the metric tree would distinguish a healthy redesign from one that merely shifts traffic, boosts short-term installs, or disadvantages certain creators.

The goal is to define a rigorous, Apple-appropriate metric framework that executives and product teams could use to evaluate the redesign, monitor ecosystem impact, identify where performance changes are coming from, and decide whether to iterate, expand, or intervene in specific markets, surfaces, or user segments.