---
title: What is Guardrail metric?
url: https://markin.ai/glossary/guardrail-metric
category: Experimentation and causality
---

# 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

- [Experiment](https://markin.ai/glossary/experiment), An 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 policy](https://markin.ai/glossary/contact-policy), Contact policy governs how often, through which channels and with what spacing a customer may be contacted.
- [Contribution margin per user](https://markin.ai/glossary/contribution-margin-per-user), Contribution 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 rules](https://markin.ai/glossary/eligibility-rules), Eligibility rules define which actions a customer may legally, commercially and contractually receive: consent status, market availability, existing plan, discount history, regulatory constraints.

## Go deeper

- [Markin product](https://markin.ai/product), Guardrails inside the loop.
- [Security and trust](https://markin.ai/security), Operating limits for autonomy.

Source: https://markin.ai/glossary/guardrail-metric