Process Models in Design and Development

Relationships across the framework categories

In this article, we have chosen to organise DDP models primarily according to their scope. This reflects the main clustering of approaches in the literature, in the sense that many articles' bibliographies concentrate on work within one of the three levels shown in Fig. 1. However, this is not the only possible organisation and interdependencies do exist between these levels. Micro-level models can provide insight relevant to the meso-level, for instance, because rework in meso-level processes is ultimately driven by design decisions made by individuals - even though those decisions' effects may unfold over a long timescale if many individuals and/or departments are involved. Similarly, meso-level models provide insight into macro-level process characteristics. For example, the patterns of information flow between two departments such as design and test will determine the level of overlapping that might be appropriate between those departments, and whether a rigid stage-gate model would be appropriate. Analyses that cross the levels as we defined them seem to be relatively rare at present. We suggest that teasing out links between the levels could be a useful direction for further work. To give just one example, insights from research into design negotiation might present opportunities to improve the probabilistic assumptions underlying treatments of iteration in some meso-level analytical models.