---
title: "One-Sample Test"
description: "How Statsig uses one-sample tests to compare an experiment group's metric against a fixed reference value rather than against a control group."
product: general
lang: en
last_updated: 2025-09-18
token_estimate: 504
---
# One-Sample Test

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A one-sample test compares one experiment group's metric against a fixed baseline instead of against a control group, and reports whether the difference is statistically significant. In Statsig, you set the fixed baseline for a metric with the _Use Fixed Baseline as Control_ option on the experiment setup page. The scorecard then compares the group against that value. Use a one-sample test when only one group can produce the metric, or when you're testing against a known target such as a 50% success rate. Use a standard two-group test whenever a real control group exists.

## When to use a one-sample test

A one-sample test fits these situations:

- **Single-group events**: When only one group can trigger certain events (for example, feature usage or error types), compare that group against an expected fixed baseline.
- **Algorithm testing**: Test whether an algorithm performs better than random (for example, whether a success rate differs from 50%).

## Enable a fixed baseline for a metric

1. Go to the setup page of an experiment.
2. Click the metric name.
3. Select **Use Fixed Baseline as Control**.

The following screenshots show the metrics section of the experiment setup page, the metric name menu, and the fixed baseline dialog.

![Experiment setup screen highlighting metrics section](https://docs.statsig.com/images/experiments/statistical-methods/methodologies/one-sample-test/742634e0-0db9-44f9-b849-0a205f604a76.png)

![Metric name dropdown showing configure options](https://docs.statsig.com/images/experiments/statistical-methods/methodologies/one-sample-test/3a645771-4771-480e-a263-15a6af951284.png)

![Fixed baseline control dialog for one-sample test configuration](https://docs.statsig.com/images/experiments/statistical-methods/methodologies/one-sample-test/9c7e85d6-e0b0-40bb-a22c-a96d7084d3e7.png)