03 · What You Need to Know
The Case Must Be More Than a Convenient Unit of Data Collection
What Exactly Is a “Case”?
A case is the bounded entity or system around which the inquiry is organized. Depending on the research problem and methodological tradition, a case might be an individual, classroom, school, organization, program, community, event, process, project, policy implementation, or another identifiable phenomenon that can be meaningfully bounded.
The important phrase is meaningfully bounded. Researchers need to establish what falls inside and outside the case. Boundaries may involve place, time, organizational membership, activity, event, program participation, or another theoretically and practically defensible limit.
For example, “online learning” is probably too broad to function as a case by itself. “The implementation of a newly introduced hybrid-learning program in one university during its first academic year” is more readily bounded. The institution, implementation process, period, participants, and contextual conditions can be specified.
Case study methodology has several traditions, and scholars do not define every feature identically. Still, the concept of a bounded case and close attention to context recur across prominent approaches. Methodological literature also emphasizes that poorly defining the case can undermine the coherence of the entire study.
Studying One Participant Is Not Automatically a Case Study
Suppose a researcher interviews one university professor about experiences using generative AI in teaching. The fact that there is one participant does not establish a case study.
The project might simply be a single interview used for exploratory purposes. It could be a biographical or narrative inquiry if the research question and analytical approach concern the person's story. It might be part of another qualitative design. Calling it a case study requires methodological justification beyond the sample size.
If the professor is genuinely treated as a bounded case, the researcher would need to explain why that particular case matters, what the boundaries are, which contextual features are relevant, and how the inquiry will develop an in-depth understanding of the case rather than merely summarize one interview.
One participant
A statement about sample size or the number of people providing data.
One case
A statement about the bounded unit around which the research inquiry and analysis are organized.
Studying One Site Is Not Automatically a Case Study Either
A similar problem occurs when researchers equate one research site with one case. Imagine administering a questionnaire to 600 students at a single university to estimate their use of generative AI.
That is a single-site study. It is not automatically a case study. If the university merely provides access to the participants and the research question concerns student-level variables rather than the university as a bounded case, the site may be a setting rather than the unit of analysis.
By contrast, if the purpose is to understand how that particular university introduced, governed, and experienced institution-wide generative AI adoption, with the university functioning as the bounded unit of inquiry, a case study design may be appropriate.
This distinction becomes especially important when deciding whether studying one or several settings actually changes the evidence. The number of sites and the number of cases are related in some projects, but they are not synonymous.
The Unit of Analysis Helps Reveal Whether You Actually Have a Case
Ask: What exactly am I trying to understand as a whole?
If the answer is a particular school, implementation, program, organization, community, event, or person in context, that entity may be the case. If the answer is instead a relationship between variables measured from individuals who happen to be located at one institution, the institution may simply be the research setting.
This is why methodological discussions of case study research often emphasize the unit of analysis. The case should be connected to the research question, not identified after data collection simply because one convenient site was available.
Bounding the Case Prevents the Study From Becoming Everything About Everything
Once you identify a possible case, determine its boundaries. Without boundaries, an apparently focused project can expand indefinitely.
Consider the case “University A's transition to online learning.” When does the transition begin and end? Does the case include every college? Students and faculty? Administrators? External technology providers? Institutional policies before the transition? Events occurring years afterward?
There is no universal boundary that must be used. The boundaries should follow the research question and conceptualization of the case. What matters is that they are explicit and defensible.
Place boundary The case may be limited to one institution, department, community, classroom, or other defined setting.
Time boundary The inquiry may cover a specific implementation period, academic year, event, project cycle, or another meaningful interval.
Activity or process boundary The case may concern a particular program, intervention, decision process, reform, or organizational activity rather than everything occurring in the setting.
Participant boundary The study may define which actors belong to the case and whose experiences provide relevant evidence about it.
Clear boundaries improve feasibility, but their purpose is not merely administrative. They define what the case actually is. Methodological work on case study research accordingly stresses bounding cases by parameters such as time and place.
Context Is Not Background Decoration
Case study research is particularly useful when understanding the phenomenon requires understanding its real-world context. The relationship between case and context is therefore substantive rather than ornamental.
Suppose two universities introduce the same learning analytics system but experience very different outcomes. Staffing, governance, infrastructure, institutional culture, training, implementation decisions, student characteristics, and prior technology practices may help explain why. A case study can investigate how those contextual conditions interact with the phenomenon of interest.
This contextual orientation is one reason case study research is often appropriate for complex “how” and “why” questions in real-world settings.
Case Studies Commonly Draw on Multiple Sources of Evidence
In-depth understanding usually benefits from evidence that illuminates different aspects of the case. Depending on the question, researchers might use interviews, observations, documents, archival records, artifacts, audiovisual materials, administrative data, or other relevant sources.
Multiple sources can help researchers examine the case from different vantage points and investigate whether interpretations are supported across different forms of evidence. This is more than collecting extra data for appearance's sake. Each source should contribute to understanding the case and the research question.
Some methodological traditions place particularly strong emphasis on multiple sources and their convergence. Contemporary methodological discussions likewise identify in-depth data collection using multiple forms of information as a characteristic of case study research.
Watch Out
Do not manufacture methodological complexity merely to earn the label “case study.” Multiple data sources are useful when they deepen understanding of the bounded case. Adding an irrelevant document, an unnecessary observation, or another interview does not compensate for an unclear research question or poorly defined case.
A Case Study Can Contain More Than One Unit of Data Collection
A single case does not mean one participant, one interview, or one dataset. A case such as a university program could contain dozens of participants, several departments, documents, observations, and quantitative records.
Researchers may also distinguish between holistic and embedded case designs. In an embedded design, a broader case contains meaningful subunits that receive analytical attention. For example, an institutional program may constitute the overall case while departments or implementation teams function as embedded units.
The boundaries of the overall case still matter. Otherwise, the project can fragment into several disconnected studies that happen to share a title.
Case Study Research Is Not Necessarily Synonymous With Qualitative Research
Case study is strongly associated with qualitative inquiry, and some methodological traditions explicitly conceptualize it as a qualitative approach. Other influential traditions treat case study more broadly as a research strategy that can incorporate qualitative and quantitative evidence.
It is therefore safer to describe what evidence is used and how it contributes to understanding the case rather than assuming that the term “case study” itself communicates the entire methodological orientation.
If qualitative and quantitative evidence are both included, that does not automatically make the project mixed methods either. Whether a project constitutes genuine mixed methods research depends on how the qualitative and quantitative components are designed and integrated, not simply on the presence of two kinds of data.
Single-Case and Multiple-Case Studies Answer Different Design Needs
A case study may investigate one case intensively or examine multiple cases. A single case may be appropriate when the case is unusually informative, theoretically important, revelatory, critical to a proposition, or intrinsically important to the research problem, depending on the methodological tradition.
Multiple-case research allows researchers to examine patterns of similarity and difference across cases. The logic is not simply “more cases equals better research.” Each case requires sufficient depth, and the rationale for selecting cases should follow the study's analytical purpose.
Adding cases can therefore increase both analytical possibilities and methodological demands. The broader principle remains the same: a more complex design should provide information that justifies the added work.
