American Institute of Certified Planners (AICP) Practice Exam

What does external validity assess in an experimental study?

1. The accuracy of the treatment's effect

2. Whether results can be generalized to other settings

3. The reliability of the sampling method

4. The consistency of the observed effects

The correct answer is: Whether results can be generalized to other settings

External validity assesses whether the results of an experimental study can be generalized to other populations, settings, times, or measures beyond the specific conditions of the study. This concept is crucial because it determines the applicability of findings in real-world scenarios. When external validity is strong, it suggests that the insights gained from an experiment can be extended to broader contexts, making the research findings more impactful and useful for informing policy, practice, or further research. Factors that influence external validity may include the characteristics of the sample, the setting of the experiment, and the nature of the treatment or intervention being tested. In contrast, other choices focus on different aspects of the research process. The accuracy of the treatment's effect pertains more to internal validity, which evaluates whether the observed outcomes are due to the treatment rather than other variables. The reliability of the sampling method is concerned with how consistently the sample represents the population, while the consistency of the observed effects deals with the repeatability of results within the study itself. These elements are essential for understanding the overall quality of research but do not specifically address the generalizability of the findings, which is the core of external validity.