> ## Documentation Index
> Fetch the complete documentation index at: https://glossary.micahealth.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Active comparator arm

The group of study participants who receive a known effective treatment or therapy, rather than a placebo. This treatment is typically an existing standard of care or previously proven medication that researchers use to compare against a new treatment being studied.

## Related terms

<CardGroup cols={3}>
  <Card title="Arm type" href="arm_type" />

  <Card title="Intervention/treatment" href="interventiontreatment" />
</CardGroup>

[*Source*](https://clinicaltrials.gov/study-basics/glossary)