Causal Relationships between Improvements in Software Development Processes and Final Software Product Quality

A main assumption of software process improvement (SPI) is that improvements in a software development process result in higher quality software products. In other words, SPI assumes the existence of causal relations between process and product characteristics. To what extent have these causal relations, however, been explored? Which specific process improvements have which particular impact on which particular product quality attributes? In this paper an overview is given of these “software process and product dependencies” (PPD). This overview comprises of a list of SPI-techniques and the associated product quality attributes that are addressed with these techniques. The extent of the causality is investigated and whether there is a possibility to identify more or less effective strategies for product quality improvement. The overview is based on a literature study and expert evaluation. The research is summarised in a matrix of both software process elements and associated software product quality characteristics. This matrix contains both satisfactory and unsatisfactory results. On the one hand, a promising extensive base of publications on techniques and methods was identified. On the other, a disappointing deficiency of empirical validation regarding the actual impact of those techniques on product quality is also prominent. As it is, we remain with an inadequate and incomplete indication of the product characteristics that particular software process improvement techniques intend to ameliorate. This article, therefore, hopefully, also provides a basis for discussion on the need to make process-product dependencies more explicit.