Guardrail metric
A guardrail metric is a measure an experiment must not damage even if the primary metric improves: unsubscribe rate, complaint volume, margin, support contacts, app uninstalls. Guardrails are declared before launch and can stop a winning variant from shipping.
Why it matters for ARPU
Almost any short-term ARPU number can be raised by borrowing from customer goodwill. Guardrails are what keep an autonomous system from doing so at scale.
Related terms
ExperimentAn experiment is a controlled release of a candidate action against a randomised holdout, sized in advance so the result can distinguish a real effect from noise.Contact policyContact policy governs how often, through which channels and with what spacing a customer may be contacted.Contribution margin per userContribution margin per user is revenue per user minus the variable costs of serving that user: delivery, payment fees, support, content or bandwidth, and any incentive granted.Eligibility rulesEligibility rules define which actions a customer may legally, commercially and contractually receive: consent status, market availability, existing plan, discount history, regulatory constraints.