A case study is a detailed investigation of a single individual or group. Case studies can be qualitative or quantitative in nature, and often combine elements of both. The defining feature of a case study is its holistic approach—it aims to capture all of the details of a particular individual or group (a small group, classroom, or even a school), which are relevant to the purpose of the study, within a real life context. To do this, case studies rely on multiple sources of data; including interviews, direct observation, video and audio tapes, internal documents, and artifacts. The final report or write-up is a narrative with thick, rich descriptions. Increasingly, case studies are being presented as multimedia packages, such as a documentary, to showcase the uniqueness and complexities of the context.
Case studies can be used for descriptive, explanatory, or exploratory purposes (Yin, 1993). For any of these purposes, there are two distinct case study designs: single-case study design and multiple-case study design. Single-case studies are just that, an examination of one individual or group. In choosing a case, researchers may purposely select atypical, or outlier, cases. An outlier case tends to yield more information than average cases. Multiple-case studies use replication, which is the deliberate process of choosing cases that are likely to show similar results. This helps to examine how generalizable the findings may be (see section on validity).
- What are the benefits of conducting a case study?
- When should I conduct a case study?
- What are the resources needed to conduct a case study?
- Study participant recruitment
- What sorts of data should I collect?
- How should I analyze this data?
- Real world example
- Published articles using case study
The main benefit of conducting a case study lies in the particular details and holistic understanding researchers gain from a specific case. Case studies allow researchers to fully understand how an intervention worked, or why an intervention had an effect in a particular case. In contrast, other forms of research, such as experimental or quasi-experimental research, do not delve into this type of detail, but rather aim to give information on whether or not an intervention has a particular, predefined effect.
All studies attempt to maximize both their internal and external validity. Internal validity addresses how valid it is to make causal inferences about the intervention in the study. External validity addresses how generalizable those inferences are to a larger population. Case studies tend to have very strong internal validity, but are often criticized because of their extremely poor external validity. Because case studies look at only one case at a time, and purposefully choose cases that are atypical, external validity is a real concern.
Case studies attempt to examine the how and why questions associated with an intervention. Case studies either describe or explain what happened in a particular case, by giving a detailed, holistic account of a particular case and allow researchers to see the product used in a natural setting. The general form of a case study research question is “How did the [specific program/intervention] work in a particular case?” Or “Why did the [specific program/intervention] have a particular effect on a particular case?”
Many other forms of research may be more appropriate for your needs, depending on your research question. For example, if one asked “What is the effect of an intervention on a specific population?” or “What is the market demand of x?”, a case study would not be ideal.
Even when there are no specific quantitative techniques or validity issues to address when implementing a case study, objectivity is extremely important. It is recommended that organizations use outside consultants or research organizations to conduct case studies. Not only does this allow the case study to be conducted by experts in interviewing, conducting focus groups, and analyzing qualitative data, but it also protects the results of the study from a perceived bias of the organization. For example, while a company with a product that aims at improving literacy in children with learning disabilities might conduct an objective, enlightening case study that shows why their product worked successfully in a specific school, school districts might not trust this result unless it was conducted and analyzed by an unaffiliated organization.
The time and cost of conducting a case study largely depends on the unit of analysis. For example, conducting a case study on a single child’s experience using a tele-therapy approach may only take a short period of time and minor costs to gain all relevant information. However, examining how and why an intervention worked within a whole school or within a large district would take much longer and would be far more expensive to gather all relevant interviews, focus groups, and other data. Before initiating a case study, you should be sure that you have the required amount of time and resources to complete it.
Elements of a case study
Recruiting study participants or study sites is critical. First, it is important that the study participants represent the population for which you hope your intervention will be effective. Second, study participants and their parents/guardians (if you are working with minors) must agree to be in the study. This involves getting parent/guardian approval through signing consent forms which describe the study and any risks and benefits that study participants may be exposed to, and then separately asking participants to consent to participate in the intervention. Because case studies examine how or why an intervention worked in a particular case, rather than testing the effects of an intervention, recruiting study participants may be much easier than with other forms of research. Furthermore, since case studies focus on one individual or group, there are fewer people who need to give consent. However, just getting individuals to agree to participate is not enough. Any studies that are funded by government agencies must have the study, data collection items, and even the consent forms approved by an Institutional Review Board (IRB) before study participant recruitment begins.
Case study research often does not keep the research participants’ identities anonymous. Cases that are presented with video, still photos, audio tapes, or other artifacts that are personally identifying offer compelling reasons to invite the participants to be active members of the research team. Consent and assent rules still apply, as does oversight by an IRB; however, these participatory cases give voice to the participant and ask participants to help interpret the findings. See more about participatory research.
It is critical that researchers conducting case studies collect as much data that may be relevant to the intervention and the context as possible. Typically, researchers will get qualitative data from interviews, focus groups, direct observations, video and audio records, and any extant documents that may pertain to the intervention and context in question. It is best to have developed interview, focus group, and observation protocols beforehand to be sure you capture the data you need to answer your study question.
Case study data tends to be qualitative in nature, and thus qualitative data analysis methods should be applied. The most common method in qualitative data analysis is “coding.” Coding is a process in which researchers analyze data for themes, either pre-determined or emerging. These can be as simple as color coding themes and subthemes with highlighters or with a word processor, or more involved, as assigning abbreviated codes to tag digital content such as audio tapes, video files, documents, etc., within qualitative software packages that can then sort and compile tagged content. Either way, codes will be study specific, depending entirely on the purpose and findings of the study. It is important for multiple researchers to ensure inter-rater reliability (that they are coding with the same assumptions and standards) by comparing and discussing their codes on a percentage of the data. This ensures researchers are thinking about the data in the same way and drawing similar conclusions. Analysis then proceeds from an interpretation of these codes and what they mean for the larger research questions. Read more about coding and other qualitative data analysis methods.
Examples and additional resources
Signing Science Dictionary: Benefits to Students and Teachers. For researcher Judy Vesel of TERC and her partners at Vcom3D, developer of the Signing Avatar® assistive technology, NCTI Tech in the Works-funded research demonstrated that a preliminary, 300-word version of the Signing Science Dictionary raised science achievement among students with hearing impairment. The unit of analysis in this study was the classroom where the dictionary was implemented, which allowed the researchers to observe and analyze the behavior and learning of students, teachers, and involved parents.
Final report of the study: http://www.nationaltechcenter.org/documents/NCTI_Report.doc
Zorfass, J. & Rivero, K. (2005). Collaboration is key: How a community of practice promotes technology integration. Journal of Special Education Technology, 20(3), 51-67.
The authors explain how STAR Tech, a professional development program, used communities of practice to help teachers work together to integrate technology tools into the curriculum to benefit students with and without disabilities. Components of the STAR Tech system include providing teachers with assistance from experts and building leadership capacity to support professional development. Findings from the study demonstrate that a community of practice can promote technology integration. This article will be of particular value to administrators interested in creating a community of practice within their school. However, what makes this article unique is that it presents a professional development program that considers the needs of teachers that service both general and special education students.
Grimes, D. & Warschauer, M. (2010). Utility in a fallible tool: A multi-site case study of automated writing evaluation. Journal of Teaching, Learning, and Assessment, 8(6).
Automated writing evaluation (AWE) software uses artificial intelligence (AI) to score student essays and support revision. We studied how an AWE program called MY Access!® was used in eight middle schools in Southern California over a three-year period. Although many teachers and students considered automated scoring unreliable, and teachers’ use of AWE was limited by the desire to use conventional writing methods, use of the software still brought important benefits. Observations, interviews, and a survey indicated that using AWE simplified classroom management and increased students’ motivation to write and revise.
 An experimental design, in contrast, aims to extricate the object of the study from the particulars.
 Yin, R. (1993). Applications of case study research. Newbury Park, CA: Sage Publishing.