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Scientists and researchers in the social sciences employ a variety of scientific methods to study real-world and laboratory-created scenarios when it comes to human behavior. One of the more misunderstood and misapplied methods is the case study.
Like any scientific method, the case study is appropriate in some instances but inappropriate in others, and is but one method a PhD student can choose as the basis for a dissertation.
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Many PhD students who are not confident about their research and/or data analytical abilities will choose a case study method for their dissertation believing that they can sidestep some of the rigor and complication of other empirical research designs. Nothing could be further from the truth.
The case study can accomplish many of the same goals as other methods. For example, the case study can be exploratory (create new knowledge), constructive (solve some problem), or confirmatory (test a hypothesis with empirical evidence). The case study can also use either a primary (the researcher collects the data) or secondary (the researcher uses someone else's data) approach. Finally, a case study can be either qualitative or quantitative in nature. The idea that case study research can only be qualitative is incorrect.
The case study can be a great method when the sample size is known ahead of time to be small. For example, suppose a professor in a university wants to study the abnormal psychology of serial killers. Certainly, there is only a small sample of people who could be the subjects of such as study. By using the case study method, a PhD researcher can still conduct the important study but avoid the problems of statistical power and other disadvantages that would be introduced by using other empirical methods.
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One of the biggest disadvantages to using the case study method has to do with external vs. internal validity. Using the case study method, the PhD researcher often does not have control over certain variables and events and, therefore, cannot control them as the researcher could in a lab experiment. Consequently, the researcher using the case study method must be content that his/her findings may only be applicable to similar cases. What the case study gains in internal validity, it loses in external validity.
Many researchers using the case study method make the mistake of relying too heavily on interpretation to guide findings and recommendations. Essentially the researcher becomes part of the research itself and, knowing the expected results, may unknowingly guide the subjects to those results, thereby confirming the expected results. This is known as the self-fulfilling prophecy or Pygmalion effect.
Finally, some members of the scientific community frown upon the case study method because researchers using it often violate the principle of falsification. In modern post-positivist scientific thought (Popper, 1959), the researcher takes the role of the disinterested observer; he/she has no vested interest in whether the research turns out one way or the other (Guba & Lincoln, 1994).
Just like any research method, the case study has advantages and disadvantages for the PhD researcher. If you are thinking of using a case study design for your dissertation or thesis, consider carefully whether it truly captures what you are trying to achieve with your research. Do not blindly choose the case study method because it fits your criteria as the method that you are most comfortable using.
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Guba, E. G., & Lincoln, Y. S. (1993). Competing paradigms in qualitative research. In N. K. Denizon & Y. S. Lincoln (Eds.) Handbook of Qualitative Research. Sage: Thousand Oaks.