Control group

The group in a trial that gets the current standard treatment, used as a fair yardstick to compare the new approach against.

The control group is the part of a trial that receives the current best treatment — the standard of care — rather than the new approach being tested. It acts as a fair yardstick: to know whether something new really helps, researchers need a comparison group to measure it against.

Being in the control group doesn’t mean getting less. In most cancer trials, it means getting today’s proven care as a floor, and sometimes a placebo is added on top so the two groups look the same. Who goes into which group is usually decided by randomization, so the comparison stays honest.