Control group
Short definition
The control group is the set of participants in a study who do not receive the intervention being tested, serving as a comparison to estimate the effect of that intervention.
In plain language
Without a comparison, it is impossible to know whether an improvement is due to the intervention or would have happened anyway. The control group may receive usual care, a placebo, no intervention or an active alternative. In virtual reality studies, the control is often usual care or another form of distraction, such as watching a video on a screen or listening to music.