Clinical Research Glossary

confounding confounding


When the study outcome is influenced by outside conditions that were not expected by the study researchers.

Example of confounding in a sentence

Researchers try to be aware of possible confounding factors that can affect their study results.

More Info

Confounding suggests there is a correlation between two or more things when really there is none.

For example, alcohol use is associated with lung cancer. Alcohol is not known to be related to lung cancer, but people who smoke often consume alcohol. Smoking is the confounder here, related to lung cancer and associated with alcohol use.

Other info to think about when joining a study

Researchers design studies to try to avoid the amount of confounding that could impact the study results. If you are thinking about enrolling in a new study, you might ask the study team how the study was designed to try to prevent confounding.

Pregnancy is often considered a confounding factor for research. Some studies are designed to not allow pregnant people to participate because they aren’t sure how the pregnancy would impact the results. If you are planning to become pregnant and are thinking about joining a study that does not allow pregnancy you should discuss this with the study team.

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