Create A/B tests by chatting with AI and launch them on your website within minutes.

Try it for FREE now

Control Group

Quick answer

A Control Group refers to a set of users in an A/B test who are exposed to the existing or 'control' version of your website, product, or marketing campaign. This group is used to compare the behavior and performance against those who experienced the new or ‘test’ version.

Key takeaways

  • Control Group helps define how an experiment is planned, run, or interpreted.
  • Clear terminology reduces confusion between marketers, analysts, designers, and developers.
  • Documenting it before launch makes results easier to trust and compare later.

Definition

A Control Group refers to a set of users in an A/B test who are exposed to the existing or 'control' version of your website, product, or marketing campaign. This group is used to compare the behavior and performance against those who experienced the new or ‘test’ version. It's a necessary component for A/B testing as it helps to establish a baseline and measure the impact of any changes.

What Control Group means in A/B testing

In practical experimentation, Control Group helps define how a test is structured and how results should be interpreted. Teams use it to align marketers, designers, analysts, and developers before an experiment goes live.

Why Control Group matters

Control Group matters because it affects how an experiment is designed, launched, interpreted, or acted on. Clear definitions help teams avoid comparing the wrong audiences, metrics, or variants.

Example of Control Group

For example, when launching a homepage experiment, the team can use Control Group to clarify the audience, variant setup, metric, or analysis method before traffic is split between experiences.

How to use Control Group

Use Control Group during experiment planning so everyone agrees on setup, measurement, and decision criteria. Document it before launch, then refer back to it when analyzing the final result.

Common mistake

A common mistake is using Control Group loosely without documenting the exact audience, metric, or variant definition. That makes test results harder to explain and easier to misinterpret later.

Related A/B testing terms

FAQ

What does control group mean in A/B testing?

A Control Group refers to a set of users in an A/B test who are exposed to the existing or 'control' version of your website, product, or marketing campaign. This group is used to compare the behavior and performance against those who experienced the new or ‘test’ version.

Why does control group matter for experiments?

Control Group matters because it affects how an experiment is designed, launched, interpreted, or acted on. Clear definitions help teams avoid comparing the wrong audiences, metrics, or variants.

How should teams use control group in an experiment?

Use Control Group during experiment planning so everyone agrees on setup, measurement, and decision criteria. Document it before launch, then refer back to it when analyzing the final result.

Download our free 100 point Ecommerce CRO Checklist

This comprehensive checklist covers all critical pages, from homepage to checkout, giving you actionable steps to boost sales and revenue.