They provide a rich source of qualitative information and they often present an opportunity to research rare disorders or situations otherwise unethical to study. They may also offer some insight on how to conduct further research in the area.
They can be invasive and potentially inappropriate, the cannot be generalised to the rest of the population and therefore have low ecological validity, they are very time consuming, they have low reliability because they are nearly impossible to replicate, and they could be subject to investigator bias because the researcher may become attached to the participant.
*TOP TIP* - The words in bold are great key words you can use to impress the examiner in your essays.
When you are evaluating research methods, you must talk about them in terms of their ecological validity.
Reading different blogs it has come to my attention that case studies are getting quite a bad reputation. They are being deemed non-scientific and of questionable usefulness. In this blog I will look at both sides of the argument for case studies and see whether as a design it is still useful for the field of psychology.
- Case studies allow a lot of detail to be collected that would not normally be easily obtained by other research designs. The data collected is normally a lot richer and of greater depth than can be found through other experimental designs.
- Case studies tend to be conducted on rare cases where large samples of similar participants are not available. An example of this is the study of Phineas Gage by Harlow, J.M. This example also connects with the point above with the depth of data obtained. Cases of brain damage are quite minimal and it is extremely rare to find people with the exact same parts of the brain affected. To be able to gain knowledge of brain functions the damage between people have to be exact to ensure you are testing the right thing, this can generally only be done through case studies.
- Within the case study, scientific experiments can be conducted.
- Case studies can help experimenters adapt ideas and produce novel hypotheses which can be used for later testing.
- Knowledge! Again to Phineas Gage, his contributions to neuropsychology and the workings of the brain are invaluable.
- One of the main criticisms is that the data collected cannot necessarily be generalised to the wider population. This leads to data being collected over longitudinal case studies not always being relevant or particularly useful.
- Some case studies are not scientific. Freud used case studies for many of his theories or studies. Such examples are that of Anna O and Little Hans. Both of these are not scientific nor are they able to be generalised. This can be attributed to them being case studies, but also Freudian theory in general.
- Case studies are generally on one person, but there also tends to only be one experimenter collecting the data. This can lead to bias in data collection, which can influence results more than in different designs.
- It is also very difficult to draw a definite cause/effect from case studies.
Case studies also tend to collect mainly qualitative data. I have put this as neither an advantage or disadvantage of case studies, as this depends on your stance on qualitative data. If you look back a few blogs I have summarised my view of qualitative data. Mainly positive!
Overall, I think that case studies are an important and useful method of data collection, especially in cases of rare phenomena. It would be extremely unethical to go taking parts of peoples brains out just to make a larger sample size to use a different experimental design method. However, as data is collected on new cases I think it is important to always refer back to previous data in order to build on existing knowledge and ensure findings are as applicable to real life as possible.