Guardrail Metrics: Don't Win the Battle to Lose the War

Guardrail metrics are your experiment's safety net, ensuring that improving one metric doesn't unintentionally harm another. They let you innovate with confidence, knowing you won't drive off a cliff while chasing a goal. In A/B testing, while you focus on a primary success metric, you also monitor guardrails like page load time, customer satisfaction, or overall revenue to catch negative side effects. The biggest mistake is focusing solely on the primary metric; a 'successful' test that hurts the user experience is a net loss.