Control group
Control group referred to in control experiments of experimental research the group of untreated or according to a usual concept of treatment (treatment as usual) treated, in all other but with the subjects of the experimental group the same study participants.
In addition to the random assignment of test subjects to control and experimental groups, the control group is a decisive criterion for the validity of research results, since otherwise an effect attributed to the experimental condition could actually be based on other causes.
Example from medicine
In a clinical study , a new active ingredient is tested on 100 subjects and shows the desired effect in 50. However, this could also be based on the placebo effect or spontaneous remission . Only a control group under ceteris paribus conditions can provide certainty.
Example from psychology
To test the hypothesis that extrinsic motivation ( reinforcement through reward) can displace an existing intrinsic motivation (acting on one's own, inner drive), Greene, Sternberg and Lepper (1976) gave elementary school students new math games and measured the amount of time for 13 days the children voluntarily spent with the games. In the following 11 days, the children received rewards for doing the same job. As predicted, after the reward was discontinued, the duration of employment fell below the initial level. Without a control group, the effect could also be explained by the fact that the games initially had the appeal of the new and over time the children became bored.
Web links
Individual evidence
- ^ Greene, Sternberg and Lepper (1976). Overjustification in a token economy . Journal of Personality and Social Psychology, 34, pp. 1219-1234