Design for Quality: the Case of Open Source Software Development

This paper proposes and examines a model of the relationship between elements of product design and software quality in open source software (OSS) development projects. Research suggests that product design, or product architecture, affects work processes and outputs in the production of goods and services. In the case of software, we therefore hypothesize that product architecture affects characteristics of subsequent code contributions, which in turn affect product quality. An analysis of 203 software releases in 46 OSS projects hosted on SourceForge.net lends support for the hypothesized relationship between software modularity and software development, suggesting that the degree of software modularity is positively associated with the number of contribution opportunities and the number of code contributions, and negatively associated with contribution size. In addition, we find that software modularity is associated with reduced software complexity, one common measure of software quality. Surprisingly we find that software modularity is associated with an increased number of static software bugs and number of bugs reported, additional measures of software quality. However, opportunities to contribute mediates the relationship between degree of modularity and number of static bugs and bugs reported to yield the expected relationship between modularity and bugs. In addition to proposing and testing relationships between elements of software development and software quality, we introduce new measures of modularity and software quality. Implications are developed for the theory of modularity and the practice of software development.