Case Study Research: Design, Philosophical Foundations, and Rigor

A case study is a methodological research approach designed to generate an in-depth understanding of a contemporary issue or phenomenon within a bounded, real-world context. It is particularly appropriate for investigating complex situations in which the boundaries between the phenomenon and its environment are not clearly defined and where researchers have little or no control over events. Commonly used in the social sciences and humanities, case study research focuses on answering “how” and “why” questions through detailed examination of an individual, group, organization, or event. Drawing on multiple sources of evidence, such as interviews, observations, documents, and archival records, case studies move beyond surface description to examine processes, relationships, and contextual influences, contributing to both theory development and theory refinement.

Case study research remains one of the most widely used and accepted strategies in the social sciences because it allows scholars to examine complex phenomena in their natural settings without reducing them to isolated variables. Emphasizing contextualized and systematic analysis, the approach provides a structured means of producing rigorous, theory-informed insight. This paper draws heavily from established methodological scholarship on case study research, including the foundational and contemporary contributions listed below.

• Bromley, D. B. (1986). The case-study method in psychology and related disciplines.
• Coombs, H. (2022). Case study research: Single or multiple [White paper]. Southern Utah University. https://doi.org/10.5281/zenodo.7604301
• Creswell, J. W., & Poth, C. N. (2018). Qualitative inquiry and research design: Choosing among five approaches (4th ed.). Sage Publications.

• Denzin, N. K. (2001). Interpretive interactionism.
• Eisenhardt, K. M. (1989). Building theories from case study research. Academy of Management Review, 14(4), 532–550.
• Feagin, J. R., Orum, A. M., & Sjoberg, G. (Eds.). (1991). A case for the case study.
• Flyvbjerg, B. (2011). Case study. In The Sage handbook of qualitative research (4th ed., pp. 301–316).
• Gustafsson, J. (2017). Single case studies vs. multiple case studies: A comparative study.
• Platt, J. (1992). “Case study” in American methodological thought. Current Sociology, 40(1), 17–48.
• Rowley, J. (2002). Using case studies in research. Management Research News, 25(1), 16–27.
• Stake, R. E. (2010). The art of case study research.
• Stake, R. E. (2015). Multiple case study analysis.
• Tellis, W. (1997). Introduction to case study. The Qualitative Report, 3(2), 1–14.
• Thomas, G. (2021). How to do your case study.
• Yin, R. K. (2004). The case study anthology.
• Yin, R. K. (2012). Applications of case study research.
• Yin, R. K. (2012). Case study methods. In H. Cooper et al. (Eds.), APA handbook of research methods in psychology (Vol. 2, pp. 141–155).
• Yin, R. K. (2016). Qualitative research from start to finish.
• Yin, R. K. (2018). Case study research and applications: Designs and methods.

Single or Multiple?

Case studies are typically defined by the intent of the case analysis and the number of cases examined. Broadly, case study designs may be categorized as single (instrumental), multiple (collective), or intrinsic case studies.

In a single case study, the researcher focuses on a specific issue or concern and selects one bounded case to explore that issue in depth. The case may involve a single individual, group, organization, event, or process. Single case designs are appropriate when the case represents a critical test of theory, an extreme or unique case, or a revelatory opportunity to examine a phenomenon not previously accessible. The emphasis is on intensive analysis within one clearly defined unit of analysis.

In a multiple (collective) case study, the researcher examines two or more bounded cases to explore a shared issue or phenomenon. The purpose is not simply to describe each case independently, but to compare cases systematically in order to identify patterns, similarities, or theoretically meaningful differences. Multiple case designs rely on replication logic, where cases are selected to produce either similar findings (literal replication) or contrasting findings for predictable reasons (theoretical replication). This design generally strengthens analytic generalization by demonstrating consistency across cases.

In an intrinsic case study, the primary interest lies in the case itself rather than in extending theory or examining a broader issue. The case is studied because it is unique, unusual, or compelling in its own right. While intrinsic case studies resemble narrative inquiry in their depth and contextual richness, they retain systematic case study procedures for data collection and analysis. The goal is a thorough, contextualized understanding of the specific case rather than broader theoretical replication.

Generalization: Analytic vs. Statistical

A common misunderstanding about case study research concerns the issue of generalization. Unlike survey or experimental designs, which aim for statistical generalization from a sample to a broader population, case study research does not rely on probabilistic sampling. Statistical generalization depends on large samples and inferential statistics to estimate how findings apply to a defined population.

Case study research instead relies on analytic generalization. In analytic generalization, empirical findings are compared to existing theory, and the case serves to support, refine, extend, or challenge that theoretical framework. The goal is not to claim that findings represent all similar cases, but rather to demonstrate how the case contributes to theoretical understanding. In multiple case designs, replication logic strengthens analytic generalization by showing that similar theoretical patterns emerge across cases (literal replication) or that predictable differences occur under specified conditions (theoretical replication).

Thus, the strength of case study research lies not in statistical representativeness, but in its capacity to produce theoretically informed insight that can be transferred, tested, or further examined in other contexts.

A Bounded System

One of the most frequently asked questions in case study research concerns the meaning of a bounded system. In this context, a bounded system refers to the clearly defined scope and limits of the case being studied. The case may consist of an individual, group, organization, event, program, decision, or process, but it must be bounded by identifiable parameters such as time, place, context, or activity. Establishing these boundaries distinguishes case study research from broader, undefined inquiry.

The concept of a bounded system is essential because it guides both data collection and analysis. By clearly specifying what is included—and what is excluded—researchers ensure coherence between research questions, unit of analysis, and evidence gathering. Scholars often describe a bounded system as a conceptual “container” that holds the relevant variables, relationships, and contextual factors associated with the phenomenon under investigation. Carefully defining these boundaries enables the researcher to maintain focus, avoid scope creep, and produce a rigorous, in-depth analysis aligned with the purpose of the study.

Philosophical Approaches to Case Studies

Case study research is not tied to a single philosophical tradition; rather, it is employed across multiple theoretical and epistemological orientations. The assumptions researchers hold about reality, knowledge, objectivity, and the role of the researcher influence how a case study is designed, conducted, and interpreted. Some approaches emphasize theory testing and analytic generalization, while others prioritize contextual understanding, co-construction of meaning, or practical problem-solving. Recognizing these differing philosophical foundations is essential for ensuring coherence between a study’s research questions, methodological choices, and analytic strategies. The table below outlines several major theoretical orientations that commonly inform case study research.

Philosophical Stance	View of Reality	Role of Researcher	Goal of Research
Positivism	Single objective reality	Detached observer	Statistical generalization
Post-Positivism	Reality exists but imperfectly known	Strives for objectivity while acknowledging bias	Analytic generalization
Interpretivism	Reality socially constructed	Interpreter of participant meaning	Contextual understanding and thick description
Constructivism	Multiple constructed realities	Co-constructor of knowledge and meaning	Thick description and interpretive insight
Pragmatism	Reality understood through practical effects	Problem-centered inquirer integrating methods as needed	Practical solutions and actionable knowledge

A positivist case study is grounded in the assumption that an objective reality exists and can be measured through systematic observation and empirical evidence. This approach is typically theory-driven and deductive, with researchers developing or testing propositions using structured research protocols designed to enhance reliability and reduce bias. Positivist case studies often combine qualitative and quantitative data, not for interpretive depth, but to identify observable patterns and potential causal relationships among variables. The case functions as a unit of analysis that contributes to broader, generalizable knowledge, and findings are expected to be replicable under similar conditions. Emphasis is placed on methodological rigor, triangulation, and transparency to avoid anecdotalism and ensure that conclusions are evidence-based rather than purely descriptive.

Post-positivist case study research, most commonly associated with Yin (2018), is grounded in the assumption that an objective reality exists but can only be understood imperfectly. Researchers operating within this tradition strive for methodological rigor while acknowledging that complete objectivity is unattainable. Post-positivist case studies typically employ clearly defined case boundaries, theoretical propositions, replication logic (in multiple-case designs), and systematic analytic techniques such as pattern matching and explanation building. The use of multiple sources of evidence—interviews, documents, observations, and quantitative data—strengthens validity through triangulation. Rather than seeking statistical generalization, post-positivist case study research aims for analytic generalization, where findings contribute to, refine, or extend theoretical understanding.

Positivist and post-positivist case study approaches share a commitment to systematic inquiry, theoretical grounding, and methodological rigor. Both emphasize structured research design, the use of multiple sources of evidence, and the development or testing of theoretical propositions. In both traditions, the case serves as a unit of analysis that contributes to broader theoretical understanding rather than remaining purely descriptive. However, they differ in their assumptions about knowledge and objectivity. Positivism assumes that reality can be observed and measured objectively, and that careful design can yield unbiased, replicable findings. Post-positivism, by contrast, acknowledges that observation is theory-laden and that complete objectivity is unattainable; instead of claiming certainty, it treats findings as provisional and subject to revision. Thus, while both pursue rigor and explanation, positivism maintains stronger claims about objectivity and certainty, whereas post-positivism tempers those claims with an awareness of epistemological limits.

Interpretivist case study research is grounded in the assumption that reality is socially constructed and understood through the meanings individuals assign to their experiences. The primary aim is to interpret how participants make sense of their social worlds, emphasizing depth, context, and subjective understanding rather than generalization. Interpretivist case studies rely on qualitative methods such as in-depth interviews, participant observation, document analysis, and sometimes ethnographic techniques to explore the “how” and “why” of human behavior within specific historical, cultural, and social settings. The researcher is viewed as an active instrument in the research process, acknowledging that interpretation is shaped by both participant perspectives and researcher insight. The goal is to produce thick description and nuanced understanding, and in some cases, to contribute to theory development grounded in lived experience.

Constructivist case study research is grounded in the assumption that reality is socially constructed and that knowledge emerges through interaction, experience, and interpretation. Rather than seeking a single objective truth, constructivist case studies explore multiple, context-dependent realities as understood by participants. The focus is on how individuals make meaning, how they interpret events, and how understanding develops over time. Researchers typically employ qualitative methods such as interviews, observations, reflective journals, and artifact analysis to examine the “how” and “why” behind lived experiences. Emphasis is placed on participant voice, contextual depth, and co-construction of meaning between researcher and participants. The goal is not analytic generalization, but rich, thick description that enhances understanding and supports transferability across similar contexts.

Interpretivist and constructivist case study approaches share a common foundation in the belief that reality is socially constructed and that understanding emerges from examining participants’ lived experiences within context. Both emphasize qualitative methods, thick description, and the importance of meaning-making rather than statistical generalization. However, they differ in emphasis. Interpretivism focuses primarily on understanding and interpreting how individuals make sense of their social worlds, positioning the researcher as an interpreter of participant perspectives. Constructivism, by contrast, places stronger emphasis on the process by which knowledge and meaning are actively constructed through interaction, often highlighting the co-creation of understanding between researcher and participants. In short, while both prioritize subjective meaning and contextual depth, interpretivism centers interpretation of experience, whereas constructivism centers the construction of knowledge.

Pragmatic case study research is grounded in pragmatism, a philosophical orientation that prioritizes problem-centered inquiry and practical consequences over allegiance to a single epistemological stance. Rather than debating whether reality is objectively discovered or socially constructed, pragmatic case studies focus on what works in addressing real-world problems. This approach commonly employs mixed methods, integrating qualitative narratives (e.g., interviews, observations, process descriptions) with quantitative indicators (e.g., outcome measures, performance data) to produce actionable and context-sensitive knowledge. A defining feature of pragmatic case study research is transparency regarding the researcher’s or practitioner’s guiding assumptions, goals, and decision-making processes, allowing others to evaluate both reasoning and outcomes. The aim is not purely theoretical generalization or interpretive depth alone, but the development of transferable insights that inform practice, policy, or intervention in applied settings.

Selecting an appropriate philosophical approach for a case study requires thoughtful alignment between the researcher’s assumptions about knowledge and the purpose of the study. Scholars seeking to test or refine theory and emphasize analytic generalization may gravitate toward positivist or post-positivist traditions. Those interested in understanding lived experience, contextual meaning, and multiple realities may find interpretivist or constructivist orientations more suitable. Researchers focused on practical problem-solving and real-world application may adopt a pragmatic stance that integrates methods as needed. Ultimately, the chosen approach should be internally coherent, linking research questions, design, data collection, and analysis so that the study is both methodologically defensible and philosophically transparent.

Ensuring Rigor

Because case study research is sometimes criticized for lacking objectivity or generalizability, establishing methodological rigor is essential. High-quality case study research relies on systematic procedures that enhance credibility, transparency, and replicability. Core strategies for ensuring rigor include triangulation, maintaining a clear chain of evidence, examining rival explanations, and documenting analytic procedures with precision.

Triangulation is a foundational strategy for enhancing the credibility, validity, and reliability of scholarly research. It involves examining evidence from multiple sources, such as interviews, observations, surveys, documents, and archival records, to strengthen interpretations and construct a coherent justification for emerging themes. By drawing on diverse forms of data, researchers increase verification, reduce bias, and improve methodological rigor. Several forms of triangulation are commonly employed. Data triangulation uses multiple sources of information related to the phenomenon under investigation. Theory triangulation applies multiple conceptual perspectives to interpret findings. Method triangulation combines different data types or research procedures to strengthen interpretive confidence. Investigator triangulation involves multiple researchers participating in data collection or independently analyzing the same data set to enhance consistency and reduce bias.

Maintaining a clear chain of evidence further strengthens rigor. A well-documented chain of evidence allows readers to trace the progression from research questions to data collection, analytic decisions, and final conclusions. This includes organizing materials systematically, preserving transcripts and artifacts, and clearly explaining how themes or propositions were derived. Establishing a case study database supports transparency and reliability by preserving the evidentiary foundation of the study.

Rigorous analysis also requires attention to rival explanations. Rather than selectively interpreting data to confirm initial expectations, researchers should actively explore competing interpretations and alternative causal pathways. Systematically addressing rival explanations strengthens internal validity and demonstrates analytical discipline.

Where to Start: Yin & Stake

The reference texts listed at the beginning of this article provide a strong foundation for scholars seeking to design and conduct case study research. Among the most influential contributors to contemporary case study methodology are Robert E. Stake and Robert K. Yin. Although case study research predates both scholars, Stake’s 1995 work helped formalize systematic procedures for qualitative case study inquiry and significantly shaped constructivist and interpretivist traditions. His books The Art of Case Study Research and Multiple Case Study Analysis remain central texts for researchers interested in contextual understanding and experiential interpretation.

Robert K. Yin has likewise played a pivotal role in advancing case study research, particularly within post-positivist and analytic traditions. Yin’s work emphasizes research design, propositions, replication logic, and analytic generalization, offering structured guidance for both single and multiple case studies. His major contributions (including Case Study Research and Applications: Designs and Methods, Applications of Case Study Research, and The Case Study Anthology) continue to shape methodological standards across disciplines. Together, Stake and Yin represent complementary yet distinct philosophical orientations that provide researchers with foundational frameworks for designing rigorous and coherent case study investigations.

Case study research occupies a unique position in the methodological landscape, offering depth, contextual sensitivity, and theoretical contribution across philosophical traditions. When designed with clearly bounded cases, coherent epistemological alignment, and rigorous analytic procedures, case studies provide a powerful means of advancing scholarly knowledge while remaining grounded in real-world complexity.