What types of research question(s) can best be addressed through the use of case studies? What are the advantages and disadvantages of the case study approach?
The case study approach is favored in many research studies in the social sciences, particularly sociology and anthropology. Case studies are useful in examining questions about a particular social group, and also explain phenomena with multiple causes, such as 'juvenile delinquency.' Finding ways to treat this sociological problem requires viewing particular types of juvenile delinquency in a sociological context, examining familial and social data as it relates to the behavior, and assessing how, for example, urban delinquency is different from 'small town' delinquency or how delinquency is practiced or viewed differently by various ethnic, racial, and religious subgroups. The question 'do female gang members in urban locations exhibit less violent criminal behavior than their male counterparts' might be a useful case study subject of study, although it should be supported with some statistical data as well.
There are, of course, some disadvantages to the case study approach and it is not a universally applicable methodology to all contexts. The group that is the subject of the case study may be so idiosyncratic that the findings are cannot be generalized to other groups. If one female gang is studied, this does not mean that all female gangs are alike, and the male control groups subjected to case studies may similarly be unique. Because case studies are commonly conducted through observation more than the use of quantitative analysis, the observer's personal bias, personal involvement with the subjects and personal subjectivity in general may interfere with the objectivity of the results.
Finally, the nature of the questions that can be asked and answered by the case study method cannot be retested by other experimenters or observers, as they are often particular to a group at a particular point in historical time the case study method thus is not a really 'scientific' approach, according to the usual interpretation of the scientific method of asking and answering a question about a hypothesis.
How does a quasi-experimental method differ from pre-experimental or experimental methods? When might a quasi-experimental design be chosen over an experimental design? What considerations must a researcher make when deciding which approach to take?
Quasi-experimental designs may include a comparison group that does not meet the strict definition of a control, or use separate samplings pre-or post-test to provide different insight upon the research. Even if the findings do not meet strict methodological standards the data may be useful if it is not ethically feasible to create a strict control group and experimental design. For example, say researchers were testing a drug that could save the lives of very sick population. It might not be valid to withhold the drug from the sick population. In a quasi-experiment the researchers could test the individuals taking the drug with and compare the information they collected with information on patients with the disease who contracted the ailment before the drug was developed. This design might be used when comparing AIDS patients before and after retroviral drugs became common. Or a comparison study might be conducted between arthritis patients using a new painkilling drug with those patients using more conventional but acceptable pain-killing treatments like NSAID (non-steroidal anti-inflammatory drugs like Advil).
Pre-experimental designs might involve preliminary research, when the actual research study is uncertain. For example, say the final research will involve subjects involved in a healthy eating and exercise program in an inner city location. To determine what the program components should include and the population that might be most in need of such a program, a case study of the area might be conducted or preliminary statistical data might be gathered about the area. A true experiment consists of a control group and an experimental group, with reproducible results. This is not always the case of a pre-experimental case study or data set, or a quasi-experimental comparison of an actual experiment with data that is not a perfect control for the findings, or was not collected under the same conditions as the research findings. Ethics and a refinement of the research process may require a quasi-experimental or…