A qualitative case study provides the opportunity to use different types of data, which enables the evidence to be triangulated

A qualitative case study provides the opportunity to use different types of data, which enables the evidence to be triangulated

This makes it possible to achieve a holistic view in the case study. The literature suggests some techniques for improving the quality and especially the validity in case studies (Yin, 2009). One of them is to use multiple sources of evidence in the data collection phase to increase the construct validity (Riege, 2003; Beverland and Lindgren, 2010). In this study, we have used field observations, internal documents combined with interviews.