Benchmarking library and application software with Data Envelopment Analysis

Library software is generally believed to be well-structured and follows certain design guidelines due to the need of continuous evolution and stability of the respective APIs. We perform an empirical study to investigate whether the design of open-source library software is actually superior to that of application software. By analyzing certain design principles and heuristics that are considered important for API design, we extract a set of software metrics that are expected to reflect the improved nature of libraries. An initial comparison by conventional statistical analysis confirms the overall belief that products of different software size scale should not be compared by simply examining metric values in isolation. In this paper, we propose the use of Data Envelopment Analysis (DEA), borrowed from production economics, as a means of measuring and benchmarking the quality of different object-oriented software designs captured by software metrics and apply this approach to the comparison of library and application software. The advantages offered by DEA and the differences between the application of DEA in an economic and a technological context are discussed. Results of the approach are presented for 44 open-source projects, equally divided between libraries and applications.