Chapter 14: Case studies Introduction 14.1 Case study design 14.1.1 The protocol 14.1.2 Data collection 14.1.3 Case selection 14.2 Data analysis and reporting 14.3 Generalising results 14.4 Conclusion

Introduction Survey for getting a little information from a large sample of the population Case study for getting much information about one member of population Techniques, e.g. Interviews, observations, etc. to gather data – quantitative or qualitative Learn from other cases: JCIT

14.1 Case study design Four possible designs on two axes Single case or multiple case Holistic or embedded Multiple case design facilitates comparison between cases Single case design may be ideal to confirm, challenge or extend a theory Holistic design considers each case in its entirety Embedded studies indicate what happens in detail of a specific part of the case

14.1.1 The protocol What is to be studied? How is the study to be done? What do you expect to learn? Theory or hypothesis to be tested Protocol helps to remain focused Test protocol before the time with pilot run

14.1.2 Data collection Quantitative Qualitative Survey for all members of the case Measure time taken by processes in the system Qualitative People’s feelings, Ethical issues, System security, Expression of threat by computer viruses Collect the kind of data that best represents the aspect you are interested in Variety Researcher may be participant observer or unobtrusive observer How are the data records kept and maintained?

14.1.3 Case selection Select a few cases randomly Select a few cases where the theory is least likely to apply Test theory in extreme cases

14.2 Data analysis and reporting Know how you plan to analyse the data Sometimes simple manipulation is not good enough Pattern matching: Predict system behaviour based on observed behaviour If collected data does not support your theory, decide which one of the rival theories may indeed be correct.

14.3 Generalising results Sometimes a single case study is enough E.g. study of how a single criminal broke into trusted cipher Multiple-case studies can prove more general results If your theory is proven in six cases, statistics show that is highly improbable that your theory does not hold.