What rationales drive architectural decisions? An empirical inquiry

Architectural decision-making is a crucial concern for researchers and practitioners alike. There is a rationale behind every architectural decision that motivates an architect to choose one architectural solution out of a set of options. This study aims to identify which categories of rationale most frequently impact architectural decisions and investigates why these are important to practitioners. Our research comprises two steps of empirical inquiry: a questionnaire (63 participants) and 13 interviews. As a result, we obtained a set of rationales that motivated architects' decisions in practice. Out of them, we extracted a list of software quality attributes that practitioners were the most concerned about. We found that, overall, architects prefer to choose solutions which are familiar to them or that guarantee fast software implementation. Mid-career architects (5 to 15 years of experience) are more open to new solutions than senior and junior practitioners. Additionally, we found that most practitioners are not concerned about the quality attributes of compatibility and portability due to modern software development practices, such as the prevalence of using specific standards and virtualisation/containerization.