> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/feature-management-experimentation/use-fme/experimentation/key-concepts/index.md).

# Key concepts

This document introduces key concepts to help you manage your team's experiments efficiently and effectively.

### Key Experimentation concepts <a href="#key-experimentation-concepts" id="key-experimentation-concepts"></a>

Experimentation is a process of testing software variants among randomized user groups to measure outcomes with statistical rigor. The following terms are foundational to understanding and running effective experiments.

| Term                                                                                                                                               | Definition                                                                                                         |
| -------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------ |
| [Statistical significance](/feature-management-experimentation/use-fme/experimentation/key-concepts/statistical-significance.md)                   | A measure of whether observed differences in outcomes are likely due to chance or reflect a real effect.           |
| [P-value](/feature-management-experimentation/use-fme/experimentation/key-concepts/p-value.md)                                                     | The probability of observing results as extreme as the current data, assuming the null hypothesis is true.         |
| [Frequentist vs Bayesian](/feature-management-experimentation/use-fme/experimentation/key-concepts/frequentist-vs-bayesian.md)                     | Two statistical approaches: Frequentist relies on long-run frequencies, while Bayesian incorporates prior beliefs. |
| [Fixed horizon](/feature-management-experimentation/use-fme/experimentation/key-concepts/fixed-horizon.md)                                         | A testing approach where results are only analyzed after collecting a pre-specified amount of data.                |
| [Sequential testing](/feature-management-experimentation/use-fme/experimentation/key-concepts/fixed-horizon.md)                                    | A method allowing results to be checked continuously without inflating false-positive rates.                       |
| [Multiple comparison correction (MCC)](/feature-management-experimentation/use-fme/experimentation/key-concepts/multiple-comparison-correction.md) | Techniques used to reduce error rates when multiple hypotheses are tested simultaneously.                          |
| [Sample size calculator](/feature-management-experimentation/use-fme/experimentation/key-concepts/sample-size-calculator.md)                       | A tool for estimating how many users are needed in a test to detect a meaningful effect with desired confidence.   |