The posting below looks at, as the title suggests, the strengths and limitations of case studies research. It is from Chapter 3, Qualitative Case Study Reseaarch in the book Qualitative Research: A Guide to Design and Implementation by Sharan B. Merriam. Revised and Expanded from Qualitative Research and Case Study Applications in Education. Copyright 2009 by John Wiley & Sons Inc. [ www.josseybass.com ] All rights reserved. Published by Jossey-Bass A Wiley Imprint 989 Market Street, San Francisco, CA 94103-1741.
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Strengths and Limitations of Case Studies
All research designs can be discussed in terms of their relative strengths and limitations. The merits of a particular design are inherently related to the rationale for selecting it as the most appropriate plan for addressing the research problem. One strength of an experimental design, for example, is the predictive nature of the research findings. Because of the tightly controlled conditions, random sampling, and use of statistical probabilities, it is theoretically possible to predict behavior in similar settings without actually observing that behavior. Likewise, if a researcher needs information about the characteristics of a given population or area of interest, a descriptive study is in order. Results, however, would be limited to describing the phenomenon rather than predicting future behavior.
Thus a researcher selects a case study design because of the nature of the research problem and the questions being asked. Case study is the best plan for answering the research questions; its strengths outweigh its limitations. The case study offers a means of investigating complex social units consisting of multiple variables of potential importance in understanding the phenomenon. Anchored in real-life situations, the case study results in a rich and holistic account of a phenomenon. It offers insights and illuminates meanings that expand its readers' experiences. These insights can be construed as tentative hypotheses that help structure future research; hence, case study plays an important role in advancing a field's knowledge base. Because of its strengths, case study is a particularly appealing design for applied fields of study such as education, social work, administration, health, and so on. An applied field's processes, problems, and programs can be examined to bring about understanding that in turn can affect and perhaps even improve practice. Case study has proven particularly useful for studying educational innovations, evaluating programs, and informing policy.
Perhaps because a case study focuses on a single unit, a single instance, the issue of generalizability looms larger here than with other types of qualitative research. However, much can be learned from a particular case. Readers can learn vicariously from an encounter with the case through the researcher's narrative description. (Stake, 2005). The colorful description in a case study can create an image: "a vivid portrait of excellent teaching, for example--can become a prototype that can be used in the education of teachers or for the appraisal of teaching" (Eisner, 1991, p. 199). Further, Erickson (1986) argues that since the general lies in the particular, what we learn in a particular case can be transferred to similar situations. It is the reader, not the researcher, who determines what can apply to his or her context. Stake (2005, p. 455) explains how this knowledge transfer works: case researchers "will, like others, pass along to readers some of their personal meanings of events and relationships--and fail to pass along others. They know that the reader, too, will add and subtract, invent and shape--reconstructing the knowledge in ways that leave it...more likely to be personally useful."
The special features of case study research that provide the rationale for its selection also present certain limitations in it usage. Although rich, thick description and analysis of a phenomenon may be desired, a researcher may not have the time or money to devote to such an undertaking. And assuming time is available to produce a worthy case study, the product may be too lengthy, too detailed, or too involved for busy policy makers and practitioners to read and use. The amount of description, analysis, or summary material is up to the investigator. The researcher also must decide. "1. How much to make the report a story; 2. How much to compare with other cases; 3. How much to formalize generalizations or leave such generalizing to readers; 4. How much description of the researcher to include in the report; and, 5. Whether or not and how much to protect anonymity" (Stake, 2005, p. 460).
Qualitative case studies are limited, too, by the sensitivity and integrity of the investigator. The researcher is the primary instrument of data collection and analysis. This has its advantages. But training in observation and interviewing, though necessary, is not readily available to aspiring case study researchers. Nor are there guidelines in constructing the final report. The investigator is left to rely on his or her own instincts and abilities throughout most of this research effort.
A concern about case study research--and in particular case evaluation--is what Guba and Lincoln (1981) refer to as "unusual problems of ethics. An unethical case writer could so select from among available data that virtually anything he wished could be illustrated" (p. 378). Both the readers of case studies and the authors themselves need to be aware of biases that can affect the final product.
Further limitations involve the issues of reliability, validity, and generalizability. A Hamel (1993, p. 23) observes, "the case study has basically been faulted for its lack of representativeness...and its lack of rigor in the collection, construction, and analysis of the empirical materials that give rise to this study. This lack of rigor is linked to the problem of bias...introduced by the subjectivity of the researcher and others involved in the case. However, this argument against case study research misses the point of doing this type of research. In a recent presentation critiquing the new "gold standard" of randomized controlled trials in educational research, Shields (2007) argues for qualitative case studies: "The strength of qualitative approaches is that they account for and include difference--ideologically, epistemologically, methodologically--and most importantly, humanly. They do not attempt to eliminate what cannot be discounted. They do not attempt to simplify what cannot be simplified. Thus, it is precisely because case study includes paradoxes and acknowledges that there are no simple answers, that it can and should qualify as the gold standard" (p. 12). These issues, which are discussed more fully in Chapter Nine, are the focus of much discussion in the literature on qualitative research generally.
In an interesting discussion of the value of case study research, Flyvbjerg (2006) sets up five "misunderstandings" about case study research, which he then dismantles, substituting a more accurate statement about the issue underlying each misunderstanding. These misunderstandings and their restatements are displayed in Table 3.1. The second misunderstanding, for example, "that one cannot generalize on the basis of a single case is usually considered to be devastating to the case study as a scientific method" (p.224). However, citing single cases, experiments, and experiences of Galileo, Newton, Einstein, Bohr, Darwin, Marx, and Freud, Flyvbjerg makes the point that both human and natural sciences can be advanced by a single case. He also argues that formal generalizations based on large samples are overrated in their contribution to scientific progress (for a discussion comparing sampling, representativeness, and generalizability in both quantitative and qualitative research, see Gobo, 2004).
TABLE 3.1. FIVE MISUNDERSTANDINGS ABOUT CASE STUDY RESEARCH. ________________________________________________________________________________ Misunderstanding Restatement
1. General knowledge is more Universals can't be found in the
valuable than context-specific study of human affairs. Context-
knowledge. dependent knowledge is more valuable.
2. One can't generalize from Formal generalization is
a single case so a single case overvalued as a source of
doesn't add to scientific scientific development; the
development. force of a single example is underestimated
3. The case study is most useful The case study is useful for
in the first phase of a research both generating and testing of
process; used for generating hypotheses but is not limited to
hypotheses. these activities.
4. The case study confirms the There is no greater bias in
researcher's preconceived case study toward confirming
notions. preconceived notions than in
other forms of research.
5. It is difficult to summarize Difficulty in summarizing case
case studies into general studies is due to properties of the
propositions and theories. reality studied, not the research
Adapted form Flyvbjerg (2006), pp. 219-245).
Eisner, E.W. (1991). The enlightened eye: Qualitative inquiry and the enhancement of educational practice. Old Tappan, NJ: Macmillan.
Erickson, F. (1986). Qualitative methods in research on teaching. In M.C. Whittrock (Ed.), Handbook of research on teaching. (3rd ed.) (pp. 119-161). Old Tappan, NJ: Macmillan.
Flyvberg, B. (2006). Five misunderstanding about case-study research. Qualitative Inquiry, 12(2), 219-245.
Gobo, G. (2004). Sampling, representativeness and generalizability. In C. Seale, G. Gobo, J.F. Gubrium, & D. Silverman (Eds.) Qualitative research practice (pp. 435-456). London: Sage.
Guba, E., & Lincoln, Y. (1981). Effective evaluation. San Francisco: Jossey-Bass.
Hamel, J. (1993). Case Study methods. Qualitative Research Methods. Vol. 32. Thousand Oaks, CA: Sage.
Stake, R.E. (2005). Qualitative case studies. In N.K. Denzin & Y.S. Lincoln (Eds.) The Sage handbook of qualitative research (3rd ed.) (pp. 443-466). Thousand Oaks, CA: Sage.
Case Study Method
Saul McLeod published 2008
Case studies are in-depth investigations of a single person, group, event or community. Typically, data are gathered from a variety of sources and by using several different methods (e.g. observations & interviews). The research may also continue for an extended period of time, so processes and developments can be studied as they happen.
The case study research method originated in clinical medicine (the case history, i.e. the patient’s personal history).
The case study method often involves simply observing what happens to, or reconstructing ‘the case history’ of a single participant or group of individuals (such as a school class or a specific social group), i.e. the idiographic approach. Case studies allow a researcher to investigate a topic in far more detail than might be possible if they were trying to deal with a large number of research participants (nomothetic approach) with the aim of ‘averaging’.
The case study is not itself a research method, but researchers select methods of data collection and analysis that will generate material suitable for case studies. Amongst the sources of data the psychologist is likely to turn to when carrying out a case study are observations of a person’s daily routine, unstructured interviews with the participant herself (and with people who know her), diaries, personal notes (e.g. letters, photographs, notes) or official document (e.g. case notes, clinical notes, appraisal reports). Most of this information is likely to be qualitative (i.e. verbal description rather than measurement) but the psychologist might collect numerical data as well.
The data collected can be analyzed using different theories (e.g. grounded theory, interpretative phenomenological analysis, text interpretation, e.g. thematic coding) etc. All the approaches mentioned here use preconceived categories in the analysis and they are ideographic in their approach, i.e. they focus on the individual case without reference to a comparison group.
Case studies are widely used in psychology and amongst the best known were the ones carried out by Sigmund Freud. He conducted very detailed investigations into the private lives of his patients in an attempt to both understand and help them overcome their illnesses.
Freud's most famous case studies include Little Hans (1909a) and The Rat Man (1909b). Even today case histories are one of the main methods of investigation in abnormal psychology and psychiatry. For students of these disciplines they can give a vivid insight into what those who suffer from mental illness often have to endure.
Case studies are often conducted in clinical medicine and involve collecting and reporting descriptive information about a particular person or specific environment, such as a school. In psychology, case studies are often confined to the study of a particular individual. The information is mainly biographical and relates to events in the individual's past (i.e. retrospective), as well as to significant events which are currently occurring in his or her everyday life.
In order to produce a fairly detailed and comprehensive profile of the person, the psychologist may use various types of accessible data, such as medical records, employer's reports, school reports or psychological test results. The interview is also an extremely effective procedure for obtaining information about an individual, and it may be used to collect comments from the person's friends, parents, employer, work mates and others who have a good knowledge of the person, as well as to obtain facts from the person him or herself.
This makes it clear that the case study is a method that should only be used by a psychologist, therapist or psychiatrist, i.e. someone with a professional qualification. There is an ethical issue of competence. Only someone qualified to diagnose and treat a person can conduct a formal case study relating to atypical (i.e. abnormal) behavior or atypical development.
The procedure used in a case study means that the researcher provides a description of the behavior. This comes from interviews and other sources, such as observation. The client also reports detail of events from his or her point of view. The researcher then writes up the information from both sources above as the case study, and interprets the information.
Interpreting the information means the researcher decides what to include or leave out. A good case study should always make clear which information is factual description and which is an inference or the opinion of the researcher.
Strengths of Case Studies
- Provides detailed (rich qualitative) information.
- Provides insight for further research.
- Permitting investigation of otherwise impractical (or unethical) situations.
Because of their in-depth, multi-sided approach case studies often shed light on aspects of human thinking and behavior that would be unethical or impractical to study in other ways. Research which only looks into the measurable aspects of human behavior is not likely to give us insights into the subjective dimension to experience which is so important to psychoanalytic and humanistic psychologists.
Case studies are often used in exploratory research. They can help us generate new ideas (that might be tested by other methods). They are an important way of illustrating theories and can help show how different aspects of a person's life are related to each other. The method is therefore important for psychologists who adopt a holistic point of view (i.e. humanistic psychologists).
Limitations of Case Studies
- Can’t generalize the results to the wider population.
- Researchers' own subjective feeling may influence the case study (researcher bias).
- Difficult to replicate.
- Time consuming.
Because a case study deals with only one person/event/group we can never be sure whether the conclusions drawn from this particular case apply elsewhere. The results of the study are not generalizable because we can never know whether the case we have investigated is representative of the wider body of "similar" instances
Because they are based on the analysis of qualitative (i.e. descriptive) data a lot depends on the interpretation the psychologist places on the information she has acquired. This means that there is a lot of scope for observer bias and it could be that the subjective opinions of the psychologist intrude in the assessment of what the data means.
For example, Freud has been criticized for producing case studies in which the information was sometimes distorted to fit the particular theories about behavior (e.g. Little Hans). This is also true of Money’s interpretation of the Bruce/Brenda case study (Diamond, 1997) when he ignored evidence that went against his theory.
Diamond, M., & Sigmundson, K. (1997). Sex Reassignment at Birth: Long-term Review and Clinical Implications. Archives of Pediatrics & Adolescent Medicine, 151(3), 298-304
Freud, S. (1909a). Analysis of a phobia of a five year old boy. In The Pelican Freud Library (1977), Vol 8, Case Histories 1, pages 169-306
Freud, S. (1909b). Bemerkungen über einen Fall von Zwangsneurose (Der "Rattenmann"). Jb. psychoanal. psychopathol. Forsch., I, p. 357-421; GW, VII, p. 379-463; Notes upon a case of obsessional neurosis, SE, 10: 151-318.
How to reference this article:
McLeod, S. A. (2008). Case study method. Retrieved from www.simplypsychology.org/case-study.html