What really is software design?

Software design has been considered an integral part of software development for over fifty years. Over this time, software developers have improved how software systems are designed and have determined which designs lead to different desired characteristics in the systems built. In parallel, software engineering researchers have studied the processes software developers use to design and have considered many aspects of software design, such as how to represent a design. Given all of the practical experience gained and all of the study about software design, you might expect that there is a sophisticated common understanding about what software design is and is not. Unfortunately, such a common understanding is not evident in the literature. To investigate how software design is perceived, we conducted an interview study involving 16 participants representing both academia and industry. Our analysis of the interview transcripts reveals five main themes: 1) design cuts across multiple development phases and involves multiple people, 2) design involved decision making, 3) design is impacted by context, 4) design involves communication and 5) good design requires experience. We discuss the implications of these themes and describe what can be done to reach a more commonly shared idea of what design represents.