8

What is a case study?

The key concept in a case study is context.

In qualitative research, case studies provide in-depth accounts of events, relationships, experiences or processes. Stemming from the fields of evaluation, political science and law, the aim of a qualitative case study is to explore a phenomenon within the context of the case¹ and to answer how and why research questions.² The contextual conditions are relevant to the phenomenon under study and the contextual factors tend to lie with the case.¹ From the outset it is important (a) to determine who or what is your case – this can be a person, program, organisation or group, or a process – and (b) to articulate the phenomenon of interest.

An example of why context is important in understanding the phenomenon of interest is a study of health promotion action by local churches in Victoria, Australia.³ The phenomenon under study was health promotion action, with 10 churches comprising the cases, which were mapped across the framework of health promotion approaches.⁴ The contextual factors included church denomination (Baptist, Church of Christ, Uniting, Anglican, Catholic and Salvation Army), size (small, medium and large), location (rural and metropolitan), partnerships with external organisations (government, local schools and social welfare organisations) and theological orientation (traditional, modern or postmodern), to understand the phenomenon of health promotion action. Data collection took 12 months and involved interviews with 37 church leaders, 10 focus groups with volunteers, 17 instances of participant observation of church activities, including church services, youth events, food banks and community meals, and 12 documentary analyses of church websites, newsletters and annual reports. The case studies identified and illustrated how and why three different expressions of church – traditional, new modern and emerging – led to different levels and types of health promotion activities.

Three prominent qualitative case study methodologists, Robert Stake, Robert Yin and Sharan Merriams, have articulated different approaches to case studies and their underpinning philosophical and paradigmatic assumptions. Table 8 outlines these approaches, based on work by Yazan,⁵ whose expanded table covers characteristics of case studies, data collection and analysis.

[table id=22 /]

Table 8.1 is derived from ‘Three Approaches to Case Study Methods in Education: Yin, Merriam, and Stake ‘  by Bedrettin Yazan, licensed under CC BY-NC-SA 4.0.⁵

There are several forms of qualitative case studies.^1,2

Discovery-led case studies, which:

• describe what is happening in the setting
• explore the key issues affecting people within the setting
• compare settings, to learn from the similarities and differences between them.

Theory-led case studies, which:

• explain the causes of events, processes or relationships within a setting
• illustrate how a particular theory applies to a real-life setting
• experiment with changes in the setting to test specific factors or variables.

Single and collective case studies, where:^{2, 9}

• the researcher wants to understand a unique phenomenon in detail– known as an intrinsic case study
• the researcher is seeking insight and understanding of a particular situation or phenomenon, known as an illustrative case study or instrumental case study.

In both intrinsic, instrumental and illustrative case studies, the exploration might take place within a single case. In contrast, a collective case study includes multiple individual cases, and the exploration occurs both within and between cases. Collective case studies may include comparative cases, whereby cases are sampled to provide points of comparison for either context or the phenomenon. Embedded case studies are increasingly common within multi-site, randomised controlled trials, where each of the study sites is considered a case.

Multiple forms of data collection and methods of analysis (e.g. thematic, content, framework and constant comparative analyses) can be employed, since case studies are characterised by the depth of knowledge they provide and their nuanced approaches to understanding phenomena within context.^2,5 This approach enables triangulation between data sources (interviews, focus groups, participant observations), researchers and theory. Refer to Chapter 19 for information about triangulation.

Advantages and disadvantages of qualitative case studies

Advantages of using a case study approach include the ability to explore the subtleties and intricacies of complex social situations, and the use of multiple data collection methods and data from multiple sources within the case, which enables rigour through triangulation. Collective case studies enable comparison and contrasting within and across cases.

However, it can be challenging to define the boundaries of the case and to gain appropriate access to the case for the ‘deep dive’ form of analysis. Participant observation, which is a common form of data collection, can lead to observer bias. Data collection can take a long time and may require lengthy times, resources and funding to conduct the study.⁹

Table 8.2 provides an example of a single case study and of a collective case study.

[table id=24 /]

Summary

Qualitative case studies provide a study design with diverse methods to examine the contextual factors relevant to understanding the why and how of a phenomenon within a case. The design incorporates single case studies and collective cases, which can also be embedded within randomised controlled trials as a form of process evaluation.

References

1. Creswell J, Hanson W, Clark Plano V et al.. Qualitative research designs: selection and implementation. Couns Psychol 2007;35(2):236-264. doi:10.1177/0011000006287390
2. Crowe S, Cresswell K, Robertson A, et al. The case study approach. BMC Med Res Methodol. 2011;11:100. doi:10.1186/1471-2288-11-100
3. Ayton D, Manderson L, Smith BJ et al. Health promotion in local churches in Victoria: an exploratory study. Health Soc Care Community. 2016;24(6):728-738. doi:10.1111/hsc.12258
4. Keleher H, Murphy C. Understanding Health: A Determinants Approach. Oxford University Press; 2004.
5. Yazan B. Three approaches to case study methods in education: Yin, Merriam, and Stake. The Qualitative Report. 2015;20(2):134-152. doi:10.46743/2160-3715/2015.2102
6. Stake RE. The Art of Case Study Research. SAGE Publications; 1995.
7. Yin RK. Case Study Research: Design and Methods. SAGE Publications; 2002.
8. Merriam SB. Qualitative Research and Case Study Applications in Education. Jossey-Boss; 1998.
9. Kekeya J. Qualitative case study research design: the commonalities and differences between collective, intrinsic and instrumental case studies. Contemporary PNG Studies. 2021;36:28-37.
10. Nayback-Beebe AM, Yoder LH. The lived experiences of a male survivor of intimate partner violence: a qualitative case study. Medsurg Nurs. 2012;21(2):89-95; quiz 96.
11. Clack L, Zingg W, Saint S et al. Implementing infection prevention practices across European hospitals: an in-depth qualitative assessment. BMJ Qual Saf. 2018;27(10):771-780. doi:10.1136/bmjqs-2017-007675