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

They found that levels of fecal calprotectin, a protein that signals inflammation in the gut, dropped significantly in the fasting mimicking group compared with the control group.

From Science Daily • Apr. 3, 2026

Participants from across the UK will be split into four groups, three of which will try out the different kinds of interventions while the fourth will act as a control group.

From BBC • Mar. 24, 2026

One of the pilots, backed by Mr. Altman, began in 2020 and provided low-income participants in Texas and Illinois with $1,000 a month, while a control group received $50 a month.

From The Wall Street Journal • Mar. 24, 2026

The authors found that people with NHL had about double the odds of being exposed to glyphosate than a control group who didn’t have the disease.

From Slate • Mar. 5, 2026

To make the retest results convincing, some non-cheaters were needed as a control group.

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