What question does internal validity address in a study?

Internal validity is focused on determining whether the observed effects in a study are truly linked to the manipulation of the independent variable, rather than other potential confounding variables. It essentially asks, "Did the intervention or treatment really induce the observed changes in the dependent variable?" This is crucial because a study with high internal validity provides confidence that the results are due to the independent variable itself.

When evaluating a study, ensuring internal validity means checking the design, implementation, and controls used to mitigate biases or other factors that could influence the results. For example, if a researcher claims that a new drug has improved patient outcomes, internal validity helps confirm that the observed outcomes are indeed the result of the drug and not influenced by external factors such as participant differences or environmental changes.

In contrast, the other options focus on different aspects of a study's quality:

• Representativeness of subjects pertains to external validity, which deals with the generalizability of the findings to a larger population.

• Standardization of data collection methods relates to the reliability and consistency of measurements rather than the causal relationships assessed in the study.

• Ethical concerns involve the moral implications of conducting research, which, while critically important, do not directly address the causal inference within the study itself.

Thus, the