Scientific control

A control experiment ( control and experimental, control experiment ) is in the exact sciences a companion experiment to exclude confounding factors or to verify the developed approach to an experiment. Control experiments are a central part of scientific methodology. In the ideal case, there are control experiments for any variable in an experiment.

Properties

Control experiments based on the ceteris paribus principle and can either exclude specific causes of a result ( negative controls ) or the basic functionality of the method represent ( positive controls ). A banded to a control experiment group is referred to as the control group.

Positive controls are accompanying experiments in which a result obtained with the main experiment phenomenon (or realized effect) occurs safely. Positive controls are used to demonstrate that a method with the known values ​​of variables works ( method validation ) and therefore can exclude false-negative results of an experiment.

Negative controls are accompanying experiments in which a result obtained with the main experiment phenomenon (or realized effect) does not occur (zero value ). Negative controls are done to exclude other reasons ( sources of error ) than the hypothesis of a phenomenon and serve an avoidance of erroneous interpretations of false positive results. Thus the possibilities of falsification of the hypothesis are reduced by a publication. Are the results of the experiment and the negative controls negative, it can be concluded that there is independence of the experimental output of the variable, ie the change of the variables did not affect the experimental outcome.

Strategies for classification of experimental groups in clinical trials are, for example, randomization and parallelization. By blind tests and double-blind additional negative controls to evaluate the impact of the level of knowledge of the subject and in the latter case, the experimenter and an experimental result are avoided.