# Clinical Trial
## Definition
A clinical trial is a:
- *planned experiment* designed to assess the efficacy of a treatment in humans by comparing the outcomes:
- in a group of participants treated with an intervention (treatment) with
- a *comparable group* of participants receiving a control treatment (i.e. placebo)
- where participants are enrolled, treated, and followed over the same time period
## Significance
Clinical trials are important because they:
1. are the definitive way to determine if a treatment is truly effective
2. determine safety of this treatment/intervention
3. improves the strength of causal inference
4. are subject to less issues of interpretation than observational studies
## Examples
- Evaluating the effectiveness of a new anti-allergy medication on congestion
- Comparing the survival of cancer patients on a new treatment versus the current medical standard
## Relevant Documents
- The [[ICH E9]] describes the statistical prinicples that should be used for clinical trials
## Stages of Clinical Trial
There are several [[Stages of Clinical Trials|stages of clinical trials]], each with a specific purpose in developing a drug for human consumption.
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# References
[[Introduction to Statistical Methods for Clinical Trials#1. Introduction to Clinical Trials]]