What does confounding in research studies affect?

Confounding in research studies primarily affects internal validity. Internal validity refers to the extent to which a study can establish a cause-and-effect relationship between the independent and dependent variables, ruling out alternative explanations for the observed effects. When confounding occurs, it means that an external factor, which is not being measured or controlled, is influencing both the independent and dependent variables. This can lead to incorrect conclusions about the relationship being studied, as the true effect may be obscured by the lurking variable that is associated with both variables of interest.

For example, if a study investigates the relationship between exercise and weight loss but does not account for participants' dietary habits, any observed weight loss may be confounded by differing diets rather than exercise alone. In this case, the internal validity of the study is compromised, making it difficult to determine whether exercise is truly the causal factor in weight loss.

Confounding does not primarily affect external validity, which pertains to the generalizability of the study findings beyond the sample used; or construct validity, which relates to how well a study measures the concept it intends to measure. It also does not directly influence operationalization, which involves translating abstract concepts into measurable variables. Hence, the focus on internal validity is crucial when discussing confounding in