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Public Health Workforce Training
Link to beginning section of Introduction to Qualitative Research

Case Study

Case study research is the exploration of an issue analyzed through one or more cases within a bounded system (Creswell 73). A case can be an individual, a program, an event, an activity, etc. so long as it exists within boundaries and is part of a larger “system.” Boundaries can be related to setting (e.g. place or time) or context (e.g. current events or environment). A case(s) may be selected to show the same or different perspectives, or because it is ordinary, extraordinary, or unusual.

There are three styles of case study research as defined by Creswell (244-245):

  • Instrumental case study. A study focused on an issue or concern. One, single case selected to serve as the vehicle to better understand the issue or concern.
  • Intrinsic case study. A study focused on the selected case because it has special or unusual interested.
  • Collective case study. A study where multiple cases are selected and examined; can be instrumental or intrinsic.”

A case is explored over time with information collected using multiple data collection methods and sources. Data from a single case is analyzed for themes which enhance understanding of the case, not for generalization outside of the case. This process, called within case analysis, provides a detailed description and major themes of the case. In a study where multiple cases are being examined, across case analysis adds a layer of depth through analysis of themes across those cases. The final product of a case study is a detailed report which should provide an in-depth description of the case, including an explanation of the bounded system, presentation case-base themes, and statements of lessons learned.

Example:

Livingwood, et al. (2013) conducted a case study that described the impact on the outcomes and organizational culture of a quality improvement (QI) project to increase immunization rates among children aged 2 years by the Duval County Health Department. Through observation of QI meetings, conducting interviews, and analyzing archival records, the authors documented the effects of application of QI on population health outcomes and agency culture. The authors asked one central question and three sub questions that guided the inquiry:

  • Were the QI processes effective in improving immunization rates?
  • What factors contributed to the success of the QI initiative?
  • What factors impeded success of the QI initiative?
  • What were the lessons learned for the public health systems and for the Duval County Health Department?

Livingwood WC, Sabbagh R, Spitzfaden S, Hicks A, Wells L, Puigdomenech S, Kramer DF, Butterfield R, Riley W, Wood DL. A quality improvement evaluation case study: impact on public health outcomes and agency culture. Am J Prev Med. 2013 May;44(5):445-52.

Challenges to consider when using case study research:

  • It can be difficult to identify a case(s) within a bounded system to study
  • Requires substantial data collection in order to present an in-depth description of the case(s)