Product metrics
A metric earns its place by changing decisions. The architecture: one north star that proxies delivered value, a small tree of input metrics teams can actually move, and guardrails that catch the damage optimization causes elsewhere.
Method
- Pick a north star that means value delivered. Not revenue (lagging, hides user harm) and not signups (vanity): a usage moment tied to the product's promise: orders delivered, documents collaborated on weekly, rides completed. Test: if this number doubles while everything else holds, is the business genuinely healthier? (see saas-metrics for the financial layer beside it).
- Decompose into input metrics teams own. North star = f(activation rate, frequency, retention, capacity...): each team owns inputs it can move with shipped work (see user-activation, churn-analysis for two of the big ones); a team goaled on the north star alone has a metric it can only watch. The decomposition is the strategy made arithmetic (see okr-cascade).
- Define every metric once, precisely. Numerator, denominator, time window, population, exclusions: written where dashboards link to it (see warehouse-modeling's metric-definition rule; saas-metrics for the canonical financial definitions). "Active user" with three definitions across three dashboards is how companies argue about reality instead of deciding.
- Stand guardrails beside every goal metric. Optimizing checkout conversion can torch refund rates; engagement pushes can burn notification opt-outs and sleep: name the 2-4 metrics each initiative must not degrade, and check them in every experiment readout (see ab-test-design's guardrail arms). A goal metric without guardrails is an invitation to strip-mine.
- Instrument events as a designed schema. Track the behaviorally-meaningful events (activation milestones, core actions, failure moments) with stable names and properties, versioned like any contract (see schema-evolution); ad hoc event sprawl produces dashboards nobody trusts (see data-quality-checks for keeping them honest). Wire the funnel from first touch through activation so drop-off is visible per step (see user-activation).
- Review metrics as decisions, not weather. A cadenced review (weekly operating, monthly deep-dive) where each owned metric gets: trend vs target, diagnosis if off, and the action being taken: dashboards without a deciding forum are decoration (see dashboard-design, infrastructure-monitoring's same rule for systems). Retire metrics nobody has acted on in two quarters.
Boundaries
- Metrics proxy value; they are not value. Goodhart applies: every proxy optimized hard enough diverges from the thing it proxied: rotate scrutiny, keep qualitative channels (support tickets, interviews: see customer-interviews) beside the numbers.
- Small products and new bets lack statistical mass; use cohort inspection and direct user contact before dashboard-driving (see mvp-scoping).
- Privacy boundaries constrain instrumentation (consent, PII in events: see pii-handling); measurement design includes what you deliberately do not collect.