Philippe Kruchten: Complexity made simple

We present a simple conceptual model of what constitutes complexity and simplicity in design engineering. At the core of the model are the three concepts of 1) scale (how many things are there), 2) diversity (how many different kinds of things are there), and 3) connectivity (how many relationships are there between things). The model distinguishes essential from accidental complexity (i.e., the complexity that we, engineers, add while designing), and intrinsic versus perceived complexity. The model also articulates the complexity of the thing (or system) we design or observe versus the complexity of the community around the system: its users, designers, manufacturers, sellers, other systems, etc.
This model is then used to articulate a set of heuristics to address complexity: reduce, hide, shrink, organize, explain, expose.. Finally we open the toolkits of engineers in various disciplines to identify strategies, methods, or tools that they can use to address complexity: design principles, guidelines, design methods, patterns, tactics, frameworks, etc. Approaches such as modeling, abstraction, partitioning can then be described in terms of  our key concepts and heuristics; e.g., “abstraction reduces perceived complexity”.  This conceptual model helps engineering students to better reflect on their practices of design, and how these practices vary across disciplines. It also provides a more systematic approach to answering the never ending question: “how can you make this simpler?

About the speaker: Philippe Kruchten is professor of software engineering in the department of electrical and computer engineering of the University of British Columbia, in Vancouver, Canada. He holds an NSRC Chair in design engineering. He joined UBC in 2004 after a 30+ year career in industry, where he worked mostly with large software-intensive systems design, in the domains of telecommunication, defense, aerospace and transportation. Some of his experience is embodied in the Rational Unified Process® (RUP®) whose development he directed from 1995 till 2003, when Rational Software was bought by IBM. RUP includes an architectural design method, known as “RUP 4+1 views”. He authored the seminal paper "The 4+1 View Model of Architecture," IEEE Software, vol. 12 (6), pp. 45-50, 1995 (>1.800 cites).