control group

American  

[kuhn-trohl groop] / kənˈtroʊl ˌgrup /

noun

1. (in an experiment or clinical trial) a group of subjects closely resembling the treatment group in many demographic variables but not receiving the active medication or factor under study and thereby serving as a comparison group when treatment results are evaluated.

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control group British  

noun

1. any group used as a control in a statistical experiment, esp a group of patients who receive either a placebo or a standard drug during an investigation of the effects of another drug on other patients

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Etymology

Origin of control group

First recorded in 1950–55

Compare meaning

How does control-group compare to similar and commonly confused words? Explore the most common comparisons:

• control group vs. experimental group

Example Sentences

See Examples For:

control group

A three-year study showed it slowed progression by 75% compared to an external control group.

From The Wall Street Journal ● Jun. 19, 2026

The company is leaning toward a trial that compares patients receiving the therapy against a control group receiving standard treatments and a “sham” procedure to rule out any placebo effect.

From Barron's ● Jun. 17, 2026

Among semaglutide users, researchers recorded 794 fractures, compared with 1,045 fractures in the control group.

From Science Daily ● Jun. 16, 2026

As a result, the number of refunds paid to customers due to items being out of stock fell by 2.6% in the treatment group, compared with the control group.

From The Wall Street Journal ● Jun. 9, 2026

Just as the scientist might randomly assign one mouse to a treatment group and another to a control group, the Chicago school board effectively did the same.

From "Freakonomics: A Rogue Economist Explores the Hidden Side of Everything" by Steven D. Levitt