control-group
UK[kənˈtrəʊl ɡruːp]US[kənˈtroʊl ɡruːp]
n
In an experiment, the group that does not receive the treatment or intervention being tested, used as a benchmark to measure the effects on the test group.
Morpheme Breakdown
control
group
control
to regulate
group
collection
Etymology
The term 'control-group' is a modern scientific compound, formed in the early 20th century within the field of experimental design. Its logic is transparent: 'control' derives from a Latin root meaning "against the roll," referring to a duplicate register used for verification, which evolved into the general sense of checking, regulating, or serving as a standard for comparison. When combined with 'group'—a word of uncertain but likely Germanic origin for a cluster or assemblage—it creates a precise term for the standard-of-comparison assemblage in an experiment. The compound elegantly encapsulates the core principle of experimental science: isolating variables by comparing a treated group against an untreated, benchmark group.
Analysis
Structure: control (to regulate) + group (collection)
- control: From Anglo-French controllen, from Medieval Latin contrarotulare (to check by duplicate register), from Latin contra- (against) + rotulus (small wheel, roll). In this compound, it functions as a modifier meaning "used for comparison or as a standard."
- group: From French groupe, from Italian gruppo, likely of Germanic origin. In this compound, it functions as the head noun meaning "a collection of people or things."
Examples
The researchers compared the results from the test subjects with those from the control-group.
To ensure the validity of the study, a placebo was administered to the control-group.
The absence of significant change in the control-group confirmed that the observed effect was due to the new drug.