control variable

[ kuhn-trohl vair-ee-uh-buhl ]

noun

1. Also control. Statistics. a person, group, event, etc., that is used as a constant and unchanging standard of comparison in scientific experimentation. Compare dependent variable ( def 2 ), independent variable ( def 2 ).
2. (in computer programming) a variable that is used to regulate the flow of control, or order of execution, generally the number of times a loop will execute.

Word History and Origins

Origin of control variable¹

First recorded in 1910–15

Example Sentences

The control variable: orange juice.

From Seattle Times

“It’s an unsexy thing to talk about,” says Harden, “but a better idea is using genetics as a control variable to work out what actually works to improve learning.”

From Nature

As the control variable in the experiment—the element that's unchanged—there was either no volunteer present or one who was empty-handed.

From National Geographic

It deleted FDA draft language saying it would review electronic cigarette cartridges to respond to evidence of poor quality control, variable nicotine content or toxic ingredients such as diethylene glycol, a chemical that the FDA said has caused mass poisonings in products such as the painkiller acetaminophen and cough syrup.

From Reuters

Our study uses a false alarm rate for tornadoes as a control variable in a model to estimate casualties and we find that an increase in the false alarm rate does translate to higher casualties. 

From New York Times