Case Studies

What are appropriate purposes of case studies, how are subjects selected, how is data collected and analysed, and what kinds of generalizations are possible?
Research designs have to be chosen in terms of the purpose of the research. Sometimes quantitative research will be more appropriate than qualitative research if the purpose is to identify the reasons behind certain problem and to make a generalization about on that phenomenon applicable to a larger population. However, in certain cases qualitative research designs can be more appropriate if the purpose is to make an in-depth study of a specific phenomenon and to investigate the variables affecting it. In the field of writing and communication where complex issues like writing process have to be studied, qualitative research designs become mostly unavoidable. Quantitative research can be a step after qualitative research identifies major variables.
Case study is a major kind of qualitative descriptive research. Its major purpose is to identify the variables affecting a certain phenomenon and to “investigate a few cases in great depth” (Farina). It tries to determine the key variables that are important to study a certain issue. In addition, it also studies the relationship between different variables, but the relationship is not that of cause and effect.
The subjects selection in case studies is quite different from quantitative research where subjects are selected through random sampling. But in case studies, a few subjects are selected to represent the major sections of the population to be studied. For instance, to study the composing process of the students (phenomenon), Emig selected eight “twelfth graders” from “a variety of types of schools: an all-white upper-middle-class suburban school, an all-black ghetto school, a racially mixed lower-middle-class school, an economically and racially mixed good school.” Graves chose eight students who were taken as “normal” by their instructors. So, what this shows is that, as a few subjects are selected in case studies, they have to be carefully chosen to best represent the phenomenon at hand.
According to the purpose of the research, data are differently collected and analyzed in case studies. The data collection methods can range from direct observation to protocol analysis, from interview to taking data from institutional records. After data is collected from different sources, the major task of its analysis is to identify the important variables. For this purpose, the researchers have to label and divide the data into different categories, which become the variables of the study. In addition, to maintain reliability, coding has to be done by more than one observers.
However, due to its focus on depth rather than on breadth, its results are not normally generalizable to a larger population. In other words, case studies enable the researchers to know “how some users act.” Its results can lead to further quantitative research. But even the case studies can at times provide generalizable results to some extent. For instance, in Janet Emig’s case, she has taken subjects from various backgrounds making her result generalizable to a reasonably larger population. Yet, since case studies do not have a broader data base as in quantitative research, its generalization is limited.