data-analytics-metric-definitionlisted

# Metric definition contract ## Purpose Two teams report "active users" and the numbers differ by 18%. Nobody is wrong; they are answering different questions. The argument that follows is never about the data — it is about a definition that was never written down, so each analyst made reasonable choices about timezone, deduplication, and what counts as activity. This skill produces the contract that ends that argument, and the restatement rules that stop the definition drifting again silently. ## Prerequisites - **Inputs:** the metric name as currently used; the decision it is supposed to support; every existing implementation of it (queries, dashboards, reports) with the numbers each currently produces; the source tables and their event semantics. - **Access:** the systems that produce the underlying events, and the person with authority to accept a definition on behalf of the business. If the two conflicting numbers cannot both be reproduced, stop. A definition written without seeing where existing implementations diverge will just become a third number. ## Procedure 1. **Write the decision the metric serves, in one sentence, before defining anything.** "We use this to decide whether to keep investing in the onboarding flow." Definitions have no correct answer in the abstract; they have a correct answer relative to a decision. A metric with no decision attached is a number the organisation maintains for free and should probably retire. 2. **Fill