It is necessary to ensure the internal validity of the study
Internal validity is a fundamental concept in experimental research, and it refers to the degree of confidence that an experiment is measuring the intended variable accurately, and the results are not influenced by any other variable. In other words, internal validity is the extent to which the researcher can confidently conclude that the observed effect is due to the independent variable and not due to any other factor.
One way to enhance the internal validity of an experiment is by using a control group. The control group is a group of participants that is treated identically to the experimental group, except that it is not exposed to the independent variable. By comparing the results of the control group with the experimental group, researchers can rule out any alternative explanations of the experimental results, such as placebo effects or natural variation.
The use of a control group enhances the internal validity of the study by reducing the likelihood of confounding variables, which are any variables that could potentially influence the dependent variable, other than the independent variable being studied. When confounding variables are not controlled for, they can lead to false conclusions about the effects of the independent variable.
Therefore, it is crucial to ensure that the control group is identical to the experimental group in every aspect, except for the independent variable being studied. This helps to establish a cause-and-effect relationship between the independent and dependent variables, and it provides a strong basis for making valid conclusions about the effectiveness of the intervention or treatment being studied.