Synergies and conflicts among software quality attributes and bug fixes

Quality has great effect on acceptance and behaviour of software products under operation. Quality has many perspectives for users, engineers and managers. These perspectives are represented formally in a quality model that is composed of both external and internal measures. External quality attributes can be measured indirectly using internal properties of the software product. Many external attributes are of interest to manager of software production and are combined in a framework or a quality model. However, these attributes may have interrelationships, positive or negative (conflicts). In addition, external quality attributes may have relationships with bugs in a component or system. In this research, we aim to find empirical evidence of the interrelationships among six quality attributes (reusability, flexibility, understandability, functionality, extendibility and effectiveness) and with bugs. We also demonstrate the evolution of these quality attributes in consecutive releases. Eleven open-source systems and their evolutions are considered to study the research objectives. The results could not show a relationship between the quality attributes and bugs in systems. The evolution of systems is consistent with the evolution in quality, i.e., quality increases in consecutive releases. There are some positive and low negative relationships among the quality attributes.