A case study is an in-depth study of one subject/participant or a small group of subjects/participants, often carried out over an extended period of time (longitudinally). Within the case study method a number of different data-gathering techniques can be used. For example, recorded interviews, case notes (of therapeutic interviews, for example), observation, as in the ape language study, and psychometric tests, which come up in the study The Three Faces of Eve. The strengths of the case study include its usefulness in describing atypical, abnormal or rare behaviour. In abnormal psychology the case study is seen as a useful way of exploring a subject/participant’s past experiences to help them deal with current difficulties. Freud’s work derives predominantly from the case studies of his patients. Another strength is that the data gathered is usually qualitative and rich in detail, so data from case studies can be highly valid. The bond of trust that can be built up between the researcher and subject/participant also means that the data is more likely to be valid than if the researcher were a stranger having only one interview with the subject/participant. The weaknesses of this method include the fact that replication is not usually possible, particularly where a therapeutic approach has been taken. This makes it hard to establish the reliability of findings from a case study. The close bond that develops between the researcher and subject/participant can be a weakness of the method too, as the researcher may lose their objectivity because of their personal relationship with the subject/participant. Their interpretations of data may also be affected by biases formed as a result of their long-term investment in the project. Generalizing from the findings of case studies can also be difficult as the cases selected for study are often unusual or even unique. Case studies can be costly in terms of both time and money.
Children as Subjects/Participants:
Practical issues: Children are often tested individually, under laboratory conditions, sometimes by an adult they are not familiar with. This set-up is designed to ensure that children do not contaminate one another’s results, that they do not simple copy a friend’s answers or respond to peer pressure. However, it is not usual for children to be out of their social environment and in the lab with a stranger. Therefore, we have to question the ecological validity of this method of testing children. Ethical issues: Can informed consent be obtained from children? Parental consent is usually sought. At what age do you think a child should be asked to give their consent? If a parent gives consent but a child does not, should the child be tested? Do you think the children have the right to withdraw? What about debriefing? Can children be debriefed?
If the outcome of a test of a particular behaviour correlates with scores on an established test of the same behaviour that has previously been agreed as valid, then the second test is described as being concurrently valid with the first. Each test supports the validity of the other.
An observer can code written material (such as articles in a newspaper) or filmed material (such as television adverts or soap operas), and this kind of observation is called a content analysis. This method eliminates the ethical concerns that arise when studying human participants, as the information being observed is already in the public domain.
Controlling Extraneous Variables
Extraneous variables are variables other then the IV that need to be controlled or kept constant in a study in order to ensure that the IV alone is the cause of any change in the DV. If an extraneous variable is not controlled or kept constant then it may operate alongside the IV and confound the study, which means we will not be able to work out whether any change in the DV is caused by the extraneous variable or...