External Validity

When an investigator wants to generalize results from a research study to a wide group of people (or a population), he or she is concerned with external validity. A set of results or conclusions [Page 467]from a research study that possesses external validity can be generalized to a broader group of individuals than those originally included in the study. External validity is relevant to the topic of research methods because scientific and scholarly investigations are normally conducted with an interest in generalizing findings to a larger population of individuals so that the findings can be of benefit to many and not just a few. In the next three sections, the kinds of generalizations associated with external validity are introduced, the threats to external validity are ...