One of the goals of Service-Oriented Computing (SOC) is to improve software maintainability as businesses become more agile, and thus underlying processes and rules change more frequently. This paper presents a controlled experiment examining the relationship between coupling in service-oriented designs, as measured using a recently proposed suite of SOC-specific coupling metrics and software maintainability in terms of the specific subcharacteristics of analyzability, changeability, and stability. The results indicate a statistically significant causal relationship between the investigated coupling metrics and the maintainability of service-oriented software. As such, the investigated metrics can facilitate coupling related design decisions with the aim of producing more maintainable service-oriented software products.

Service-Oriented Computing (SOC) is intended to improve software maintainability as businesses become more agile and underlying processes and rules change more frequently. However, to date, the impact of service cohesion on the analyzability subcharacteristic of maintainability has not been rigorously studied. Consequently, this paper extends existing notions of cohesion in the Procedural and OO paradigms in order to account for the unique characteristics of SOC, thereby supporting the derivation of design-level software metrics for objectively quantifying the degree of service cohesion. The metrics are theoretically validated, and an initial empirical evaluation using a small-scale controlled study suggests that the proposed metrics could help predict analyzability early in the Software Development Life Cycle. If future industrial studies confirm these findings, the practical applicability of such metrics is to support the development of service-oriented systems that can be analyzed, and thus maintained, more easily. In addition, such metrics could help identify design problems in existing systems.