Single case study designs are used to study a situation or context that is a critical, single, longitudinal case (Yin, 2014, p. 51). The multiple case study design, on the other hand, attempts to replicate findings in multiple cases to allow generalization of the findings. Furthermore, another important aspect of case selection in several case studies concerns the criteria and rationale for case selection (Gray, 2014; Yin, 2014). Obvious differences between single and multiple holistic case studies are incorporated into the unit of analysis. In holistic design, the unit of analysis is single, while an integrated approach uses multiple units of analysis. In other words, a multiple case design allows two or more cases to be replicated or deliberately reproduced.