1.3 Research Approach (p. 10)

A detailed definition of the case study has been provided by Yin (2003): "A case study is an empirical inquiry that investigates a contemporary phenomenon within its real-life context, especially when the boundaries between phenomenon and context are not clearly evident. The case study inquiry copes with the technically distinctive situation in which there will be many more variables of interest than data points, and as one result relies on multiple sources of evidence, with data needing to converge in a triangulating fashion."

Case studies are thus characterised by the use of data from various sources, including archives, interviews, surveys and observation to develop a holistic analysis. Their aim is to answer "how" and "why" questions. Their results can be qualitative, quantitative or a hybrid of both of them.

Regarding the data for my case studies, I have collected material from different sources, combining existing literature, official documents by public authorities (such as the European Commission, the European Regulators Group, Bundesnetzagentur, the German monopoly commission and Ofcom) as well as documents by supranational research institutes (such as OECD and ITU). Finally, I conducted seventeen semi-structured interviews with twenty two market experts to gain a deeper understanding of causal relationships in the broadband markets of Germany and the UK.

However, when researchers mix different kinds of data, they have to be aware of problems related to triangulation. Originating in navigation and military strategy where multiple reference points are used to locate an object’s exact position triangulation describes the process of combining different selection procedures, data collections, test arrangements and different techniques of measurements in order to compensate for the weaknesses of particular methods. Oppermann (2000) points out that scientists using triangulation have to be very thorough in their research design. Blaikie (1991) postulates that all measurement should be of the same kind and based on a common ontology and epistemology. Generally it seems appropriate to follow the estimation of Fielding/Fielding (1986):

"We should combine theories and methods carefully and purposefully with the intention of adding breadth and depth to our analysis but not for the purpose of pursuing "objective" truth."

Thus, the emphasis lies in its use as data and investigator triangulation and not in its use as multi-method and multi-theory approach. Therefore, triangulation may enable us to improve the accuracy of our judgments by collecting different kinds of data to gain purchase on the same phenomenon.

The problem of triangulation is considered by the use of an integrative framework with a strong theoretical background. This procedure assures that different kind of data are analysed in the same way, and in particular with respect to a common ontology and epistemology. When using case studies, researchers have to pay attention to certain disadvantages related to this approach, especially with regard to the generalisability of the results obtained from one particular case. Yin (2003) points at three usual prejudices against case study analysis:

Perhaps the greatest concern has been over the lack of rigor of case study research. Too many times, the case study investigator has been sloppy, has not followed systematic procedures, or has allowed equivocal evidence or biased views to influence the direction of the findings and conclusion.[...]