What Is a Control Group?

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A control group is a group of individuals or cases that are assigned to an experimental group and are treated the same as the experimental group; however, they are not aligned with the experimental treatment or the experimental factor. In scientific testing, the control group is important because they ensure that placebo effects can be separated from the actual outcome of each experiment.

Control groups will sometimes be called "controls" or "control treatments." A controlled experiment is an experiment that uses a control group. "Control" is a term used in scientific testing that involves using a control group in order to keep a variable constant so that the impact of the experimental factor can be better known and understood.

The term "control group" first originated between 1950and 1955. In control groups, scientists are careful to choose subjects that have similarities in demographic values as those in the non-control or experimental group. This helps with making the comparisons between the two groups and determining the effectiveness of the experiment or treatment. An example of a control group would be a volunteer group that was not given any meditation training compared with an experimental group of volunteers that were given 8 weeks of training in meditation.