Design change and complexity

Design changes can be surprisingly complex. We examine the problems they cause and in what ways they are complex, mostly in the area of engineering design change. To assist this analysis we distinguish between (i) a static background of connectivities designs, processes, resources and requirements, (ii) descriptions of these elements and (iii) the dynamics of design tasks acting on descriptions. The background might consist of existing, similar designs, ways of describing them and established processes used to create them. We view design change, and design more generally, in terms of this model of background structure, associated descriptions and actions on descriptions. Sources of complexity in design change are examined and we indicate where these occur in different aspects of the model.