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Guardrail metric

A guardrail metric is a measure you monitor during a test to make sure the change does not cause harm elsewhere.

Written by Reflective Data experts · updated Oct 5, 2026

A change might lift sign-ups while hurting page speed, support tickets or revenue per user. Guardrails catch these side effects before you ship.

Define them before the test, alongside the primary metric.

related

A/B testConversion rateSample ratio mismatch (SRM)

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We set up, audit and run experimentation programs on any tool. A/B testing services → · Audits

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