Quality of Case study

To establish the quality of any empirical social research, four tests have been used that are common to all social science methods [100]. The four tests are construct validity, internal validity, external validity and reliability. Yin [101] describes case study tactics for dealing with these four tests. For each test the tactics are explained which are used for this case study.

Construct validity

Construct validity is about identifying the correct operational measures for the concepts being studied [100]. For this research, the case study focused on trends in virtualization technologies. Construct validity in this case is about how much the findings reflect the virtualization trends in the real world. Yin [101] describes three tactics to increase construct validity when doing case studies. These are using multiple sources of evidence, establish a chain of evidence and have the case study report reviewed by key informants. For this research one of the three tactics can clearly be identified. First of all, multiple sources of evidence were used. Interviews were conducted with experts of different organizations. However, the goal was to contact a larger group of experts with expertise in all the different virtualization domains. More respondents are needed to research the business opportunities of virtualization technologies, but the two cases did provide information about the main virtualization trends.

Internal validity

Internal validity is for explanatory case studies that are seeking to establish a casual relationship, whereby certain conditions are believed to lead to other conditions [100]. Tactics are pattern matching, explanation building, addressing rival explanations and using logic models. The case studies of this research can be described as an exploratory study, because it seeks to identify trends and are not concerned with this kind of causal situation. Therefore internal validity is applicable for explanatory studies and not exploratory studies.

External validity

External validity deals with the generalization of the research findings beyond the immediate case study. The external validity test is concerned with extent to which the results of a case study can be held true for other case studies. The advised tactics are to avoid using single cases, because they offer a poor basis for generalization [100]. In this case study, two cases have been used of which the results were compared. The results were very similar and provided many views on the matter. The differences in answers between respondents are not contradictions of other results, but give additional insight in what is going on. The questions that were being asked were very open and one answer is not better than the other, but provided an additional view on the subject at hand. When more cases or respondents are added to the case study, it is expected that this will lead to more insights instead of contrasting results.

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Reliability

Reliability is about demonstrating that if study is repeated the same results will follow. The emphasis is about doing the same case over again and not replicating the results of one case by doing another. The tactic for this test is to make as many steps operational as possible and to develop a case study database. In section 6.1, the research procedures of the case study have been described, which can be used to repeat the case study. Also, in appendix D the collected data is stored with detailed reports of the interviews that can be reviewed.

6.6 Summary and outlook

The case study provided a lot of information about the main virtualization trends, but also constructive remarks on the taxonomy model. The overall findings of the virtualization trends are that the desktop virtualization and management technologies are becoming very popular and receive much attention by virtualization vendors. Reasons are that organizations seek new flexible way of offering work places and traditional management tools are insufficient for virtual environments. For successful management of virtualization environments, tools are needed that are virtualization aware and provide more functionality to manage virtual environments effectively. Furthermore, management issues have been addressed and the main business reason for virtualization is in particular cost savings. By tackling the issues of virtualization more cost savings are possible. Furthermore, security is also seen as very important. Security tools for virtualization are expected to receive much attention in the coming years. In the case study the answer has been given of the fourth and last research question that states:

 What are the virtualization trends?

The case study provided much insight in the trends of virtualization technologies. However, regarding the business side of the technologies more research is needed to discuss the business aspects in more detail. The number of respondents was insufficient to explore all the virtualization domains for business opportunities.

In chapter 7, a new taxonomy model is presented that has taken into account the remarks of the experts of the case study. Chapter 8 reflects on the choices made throughout the course of this research project. In chapter 9, conclusions are given that answer the main research question. Also, recommendations have been made for Atos Origin in which possible business opportunities are discussed based on the research findings.

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