What does internal validity ensure in an experiment?

Internal validity refers to the extent to which an experiment allows for valid conclusions about the relationship between the independent and dependent variables, meaning it ensures that any observed changes in the dependent variable are directly attributed to the manipulation of the independent variable, rather than to other extraneous factors.

When internal validity is high, researchers can confidently assert that the results of their experiments reflect true cause-and-effect relationships. This is achieved by controlling for confounding variables that could influence the outcome. In this way, internal validity focuses specifically on eliminating alternative explanations for the observed results, ensuring that the experiment is measuring what it intends to measure without interference from outside influences.

While other aspects, such as generalizability to different populations or adherence to ethical guidelines, are important for overall research quality and external validity, they do not specifically address the core concern of internal validity, which is the integrity of the causal relationship within the study itself.