Granularity of Services - An Economic Analysis

Service-oriented architectures are widely discussed as a design principle for application and enterprise architectures. Nevertheless, an adequate granularity of services from an economical perspective has not yet been researched sufficiently. The finer the granularity to realize the functions of a process, the higher is the number of services and the more effort has to be spent to compose them. In contrast, very course-grained services bear the disadvantages of higher implementation costs and lower reuse potential (e.g. in different processes). The decision model proposed in this paper is to determine an adequate granularity of services from an economical perspective. In this way degrees of freedom, which often exist for the choice of granularity after a domain analysis, can be used. We demonstrate the decision model in the context of a financial services provider in order to illustrate its applicability and practical benefits.