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CONCEPT Cited by 1 source

Metric definition drift

Definition

Metric definition drift is the anti-pattern where different teams independently maintain their own SQL/logic for the same business metric, resulting in subtly different definitions that produce different numbers for the same question. It emerges naturally as organizations scale: products launch, teams rotate, people leave, and the tribal knowledge of "what Metric ABC actually means" fragments.

Symptoms

  • Different dashboards show different numbers for the same metric
  • Stakeholders lose trust in data ("which number is right?")
  • Outdated definitions silently creep into decision-making pipelines
  • Reconciliation meetings consume engineering time
  • ML models trained on one definition diverge from monitoring dashboards using another

Root causes

  • No centralized version control for metric definitions
  • No shared standard or single authority on what a metric means
  • Team turnover erodes institutional knowledge
  • Copy-paste SQL proliferates across codebases

Solutions

The standard remedy is a headless BI semantic layer or metric-as-code approach — define once, consume everywhere. Lyft's Metric Semantic Layer is a canonical example: a versioned Python package where each Golden Metric's SQL is defined once and distributed to all consumers.

(Source: sources/2026-06-10-lyft-metric-semantic-layer)

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