Agile vs. plan-driven perceptions of software architecture

The use of agile methodologies in industry has increased significantly over the past decade, promoting the value of human-centric software development process. This growing use derives the need to adjust agile methodologies to bigger, more complex system development projects, where architecture plays a significant role. However, many believe that an essential conflict exists between the requirement of minimalism in agile methods and the need for well-defined and documented architecture in complex systems. This paper presents an exploratory study aimed at understanding the software architecture related activities as perceived by architects with and without experience in agile methodologies. The findings indicate that while architects practicing only plan-driven methodologies perceive architecture activities as being related only to the first phases of the development process, architects involved in agile projects perceive architecture activities to be related to most or all phases of the development lifecycle. The latter perceptions are consistent with suggestions expressed in the literature regarding architecture in general and in agile methodologies in particular. Based on these findings we suggest that agile methods not only lead architects to adjust their behavior to the agile philosophy, but also improve architects´ perceptions and practice of architecture in general.