Validity

Conceptual Overview and Discussion

How is one able to trust the conclusions of case study research and judge the extent to which the findings actually speak to the concepts with which the research and case (or cases) are concerned? This discussion of validity is at the heart of these vexing questions. However, there is no easy, formulaic approach to assessing validity in case studies. This is because there are both a wide range of types of validity as well as a preponderance of different types of data and approaches to case studies. If one believes that it is advantageous to have a broad range of perspectives and approaches within the social sciences, then one must contend with the fact that an equally appreciative and nuanced understanding of validity as it applies to many different research contexts is required.

Often, validity is mistakenly assumed to be concerned only with issues of measurement. This reflects a presupposition of both quantitative data as well as philosophic/ontological presumptions of an independently existing social reality. This narrow appreciation of the underlying quality concerns regarding research offers a quandary whereby we desire assurances about the quality of the research but lack a programmatic checklist of characteristics to assess. Indeed, although fundamental concepts of trustworthiness are found across research traditions, the particular ways of assessing such legitimacy are deeply and historically rooted in each tradition. This being the case, this entry examines a variety of types of validity, but without a prescriptive formula for any general application to case studies. Through the use of some examples, the implications of different types of validity are illustrated.