Shopify blog
Guardrail metrics track side effects from a product change, campaign, or experiment. Teams use them with the main success metric to see whether growth in one area creates problems elsewhere, such as more refunds or higher churn.
Testing new business strategies can raise conversion or engagement, but also create issues that hurt the customer experience or increase operating costs. In PwC’s 2025 Customer Experience Survey, 52% of consumers said they stopped using or buying from a brand after a bad product or service experience.
This guide covers how guardrail metrics work and how to use them to make product and marketing decisions.
What are guardrail metrics?
Guardrails in business are limits or checks that help teams stay within acceptable ranges while they make changes. Guardrail metrics are counter metrics that track whether an A/B test or multivariate test is creating unwanted side effects in areas such as retention or margin.
Businesses use guardrail metrics together with a primary metric for an experiment:
- Primary metric. Tracks the intended result, such as more sign-ups or a higher average order value (AOV).
- Guardrail metric. Tracks what should stay stable, such as churn, return rate, or page speed.
For example, a checkout test may increase completed orders. If refund requests or payment errors also rise, the guardrail metric shows the tradeoff. The team can then decide whether the change is worth keeping.
Success metrics vs. guardrail metrics
Success metrics show whether a team is reaching its goal. Guardrail metrics show whether that progress has negative or even deal-breaker consequences.
In an experiment, there are additional success metrics to consider:
| Metric type | What it tracks | Example |
|---|---|---|
| Primary metric | The main result the team wants to improve | Average order value |
| Secondary metric | Related results that add context | Items per order, repeat purchase rate |
| Guardrail metric | Outcomes that should stay within an acceptable range | Cart abandonment, page speed, churn |
| North star metric | The long-term business goal teams work toward | Customer lifetime value, repeat purchase rate |
For example, a boutique cat apparel business wants to increase average order value. The product team adds an upsell at checkout, so a customer buying a silk vest sees a suggested bow-tie collar.
Average order value is the primary metric and cart abandonment rate is the guardrail metric, because it shows whether, and if so, how much the upsell adds friction before purchase.
Benefits of guardrail metrics
Guardrail metrics provide employees with a framework to guide their decision-making. Some of the benefits associated with using them are:
Protect profitability
Track key KPIs such as margin, fulfillment costs, and return rates. A 2025 Shopify survey of store owners* found that 42% of merchants cite ensuring profitability as their top business goal. With guardrail metrics, stores can avoid making changes that raise revenue but lower profit.
Focus tests on retention
A/B tests often focus on conversion, but retention shows whether customers continue buying after the change. In a 2025 Ascend2 survey of 402 marketing professionals who run A/B tests, 46% selected customer retention rate as a metric for evaluating A/B test results. Stores can measure whether a change drives short-term sales without hurting repeat purchases.
Reduce return and refund risk
Returns and refunds can show whether a campaign or product adjustment is causing post-purchase issues. The National Retail Federation (NRF) and Happy Returns projected that total retail returns would be $849.9 billion in 2025, and almost 20% of all online purchases. Guardrail metrics related to returns help stores spot product, pricing, or messaging issues that lead to returns.
Create accountability across teams
Kameleoon’s 2025 experimentation-led growth report found that 35% of testing businesses have fully integrated their experimentation technology across marketing, product, and engineering teams.
Guardrail metrics give teams the same rules for reviewing a test. Shared rules make it easier to objectively review a change by its affect on sales, customer behavior, and operations.
Types of guardrail metrics for ecommerce businesses
Ecommerce guardrail metrics track what should not get worse while a team tests a change. Choose metrics based on where the change affects the customer journey, operations, or profit.
| Category | What it helps protect | Example guardrail metrics |
|---|---|---|
| Checkout | The path from cart to completed order |
|
| Customer experience | The quality of the shopping experience before and after purchase |
|
| Site performance | Site speed, reliability, and usability during browsing and checkout |
|
| Retention | Whether customers continue engaging or buying after a change |
|
| Profitability | Whether growth is improving revenue without reducing margin |
|
| Fulfillment | The cost and reliability of getting orders to customers |
|
| Product quality | Whether customers receive what they expected |
|
Tips for choosing and implementing guardrail metrics
Guardrail metrics define acceptable risk before a test begins. The team decides which outcomes can change, how much change is acceptable, and what action to take if a metric crosses that limit.
Choose a small number of guardrails tied to the most likely risks. Too many metrics can make test results harder to read and decisions harder to make.
Follow these five tips:
- Define the primary goal
- Identify the likely downside
- Choose 1 to 3 guardrails
- Set thresholds and actions
- Review results in reports
1. Define the primary goal
A guardrail metric has three parts:
- A number to show what the team is tracking
- A threshold that sets the limit
- An action that tells the team what to do if the metric crosses that limit
Set thresholds before adding more spend or rolling out a change to more customers. A 2025 Shopify survey of store owners found that 19% of merchants wish they had waited for profitability before scaling.
Profit guardrails can show when a campaign, product test, or new channel needs more review before the team invests further.
Examples:
- Pause a landing page test if bounce rate rises above 40%.
- Revise an email campaign if the unsubscribe rate rises above 0.5%.
- Stop increasing ad spend if gross margin falls below the target range.
2. Identify the likely downside
Name the risk associated with each guardrail. A change can improve one result but disturb another function.
Some ecommerce tests that can impact the business are:
- Pricing. Discounts can increase orders but lower margin or increase refund requests. Track gross margin and return rates.
- Checkout. Upsells or added form fields might change how many customers finish a purchase. Monitor cart abandonment and checkout completion.
- Loyalty. Rewards or member deals can affect profit per order or repeat purchase. Measure redemption rates and margin per order.
3. Choose 1 to 3 guardrails
Choose guardrails that can change the decision at the end of the test. A long list of metrics will make results harder to review. Only include metrics that help decide whether to keep, change, or stop the experiment.
Base each guardrail on the main risk. For example, a checkout upsell may need guardrails for cart abandonment, payment errors, and refund rate.
Before adding a metric, ask: Would the team change the test if this number got worse? If the answer is yes, include it in the test plan.
4. Set thresholds and actions
Set a limit for each guardrail before the test starts. A limit shows the acceptable range. Then document what to do if the results move outside that range.
For example, a store testing a 15% discount may use gross margin as a guardrail. They may keep the discount live as long as gross margin stays within the target range. When gross margin falls below that range, they’d lower the discount, limit the promotion to certain products, or stop the test.
5. Review results in reports
Review the primary metric and guardrails in the same reporting view when possible. Shopify Analytics dashboards show store performance across areas such as sales, sessions, and fulfillment.
Businesses can also:
- Edit reports
- Filter data
- Change columns
- Save custom data explorations
For example, a store testing a new onsite personalization app may use conversion rate as the primary metric. Cart abandonment and gross margin are the guardrails. A custom report lets marketing, ecommerce, and finance review the same test before deciding whether to keep the app.
Consider partnering with team leaders from different departments to understand how your changes could affect the broader organization. Aim to develop guardrail metrics that consider each team’s needs.
Examples of guardrail metrics
Guardrail metrics help companies accomplish their goals without jeopardizing the customer experience or product quality. Consider these hypothetical examples to learn how different types of ecommerce companies might use guardrails to balance short-term and long-term growth:
Handmade craft marketplace
Primary metric: Increase website transactions.
Possible downside: Orders may increase faster than sellers can respond to messages, ship products, or maintain quality.
Guardrail metric: Track seller performance statistics such as message response rate, on-time shipping, review rating, and case rate. Etsy uses these same categories in its customer service standards for sellers.
Threshold/action: Define seller performance guardrails before the test begins. If transactions increase but message response rates, on-time shipping, review ratings, or case rates fall outside the accepted range, pause the test and assess which seller groups are driving the decline.
Beauty supply retailer
Primary metric: Increase loyalty program enrollment.
Possible downside: Customers may join for a discount, then stop opening emails, redeeming rewards, or buying again.
Guardrail metric: Track repeat purchase rate, reward redemption rate, email engagement, and unsubscribes.
Threshold/action: Set retention and engagement thresholds for new loyalty members before launch. If loyalty enrollment rises while repeat purchase rate, reward redemption, or email engagement falls below target, refine the offer or pause the campaign until quality of participation improves.
Resale marketplace
Primary metric: Increase product listings.
Possible downside: More listings may make the marketplace larger without making it easier for buyers to find products they want. Listings can grow while purchases, messages, or search quality decline.
Guardrail metric: Track marketplace liquidity, which is how efficiently a marketplace matches buyers and sellers.
Threshold/action: Establish liquidity thresholds before increasing listing volume. If product listings grow while listing-to-sale rate, buyer-to-seller message rate, or search-to-purchase rate declines below target, improve listing quality, categorization, or search filters before scaling supply further.
Read: Demand Forecasting Software for Retail and Ecommerce
Peak traffic campaign
Primary metric: Increase conversion rate during a high-traffic sales period.
Possible downside: More traffic can slow the site or create friction at checkout. Shoppers may leave before completing their purchase.
Guardrail metric: Monitor site speed and checkout completion. Audio Advice moved to Shopify before Black Friday Cyber Monday and reached 100% Core Web Vitals compliance across all pages after the migration. The brand also saw a 47% year-over-year increase in conversion rate.
Threshold/action: Set a minimum site speed and checkout completion rate before the campaign starts. If either metric falls below that range, reduce page weight, simplify campaign pages, or pause lower-priority promotions until performance improves.
*Based on a 2025 survey of 500 Shopify merchants conducted in English across Australia, Canada, the United Kingdom, Ireland, New Zealand, and the United States. Respondents were established merchants with two or more years on the platform. Results reflect the experiences of this specific sample and may not be representative of all merchants.
Guardrail metrics FAQ
What is a guardrail metric example?
Cart abandonment rate is a guardrail metric for a checkout test. If a new upsell increases average order value but more shoppers leave before completing checkout, the team can revise or stop the test.
What is a guardrail KPI?
A guardrail KPI is a key performance indicator that tracks unwanted side effects from an experiment. In ecommerce, these could be return rate, churn rate, page load time, or gross margin.
What is the difference between counter and guardrail metrics?
The terms are interchangeable. Companies implement guardrail metrics to protect critical business metrics during product and marketing experiments and A/B tests.
How do you set guardrail metrics?
To set guardrail metrics, start by defining the primary goal of your initiative. Evaluate the risks associated with your experiment and consider how they might affect important marketing objectives and business goals. Develop clear and actionable metrics to protect your company’s performance and reputation.
What are guardrail metrics in product management?
In product management, guardrail metrics track risks linked to a product change. For example, a product team may track conversion rate as the primary metric and use refund rate, ticket volume, or page speed as guardrails.
