One-Sample Test
How Statsig uses one-sample tests to compare an experiment group's metric against a fixed reference value rather than against a control group.
One-sample tests (fixed-value test)
A one-sample test compares a single sample of data against a known or hypothesized value to determine whether there is a statistically significant difference. Unlike A/B tests that compare two groups, one-sample tests evaluate whether a single group differs from a specific benchmark, target, or historical baseline.
When to use one-sample tests
One-sample tests are useful for comparing a single group against a known value:
- Single Group Events: When only one group can trigger certain events (for example, feature usage or error types), compare against an expected baseline.
- Algorithm Testing: Test whether an algorithm performs better than random (for example, whether a success rate differs from 50%).
Statistical considerations
One-sample tests provide a way to make statistical inferences about whether observed data differs significantly from a hypothesized value. The test helps determine whether any observed difference is due to random variation or represents a true change in the underlying process.
Enable fixed-value baseline comparison
- Go to the setup page of an experiment

- Click the metric name

- Select Use Fixed Baseline as Control

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