Process Models in Design and Development
Read this article. It provides an overview of planning models. Pay particular attention to Figure 1 as it visually provides a global view of planning models. Then review Figures 2 -17 for more in-depth visual planning processes.
Introduction
In comparison to many other processes, the design and development process (DDP) is especially challenging to navigate and manage. Researchers have developed numerous process models to understand, improve, and support the DDP considering its particular characteristics. However, the complexity is such that no single model can address all the issues. Furthermore, the many models that have been developed are diverse in focus and formulation. This article aims to summarise the current thinking in the area by providing an up-to-date overview of DDP models, and by developing an organising framework that positions them in relation to one another.
The models we consider are motivated by, and aim to address, certain characteristics of the DDP that distinguish it from many other processes. In particular, the DDP tends to involve significant elements of novelty, complexity, and iteration. The following paragraphs introduce these interrelated issues and outline how process models can help to address them, before moving on to discuss this article's contribution.
First, considering novelty, "design processes seek to do something novel, once, whereas many other business processes seek to do the same thing repetitively". In consequence, every DDP is unique and involves a degree of uncertainty. New activities are typically discovered during projects; the process sequence is unpredictable, because tasks are progressively concretised and adjusted as work proceeds; and decisions must often be based on inadequate or preliminary information. These issues may be observed on all levels of scale, from designers working alone through to complex development programs.
Second, considering complexity, large-scale concurrent engineering in particular involves many tasks and individuals, a densely connected web of information flows, and many interdependent design issues that must be considered simultaneously. Feedback processes within a DDP are also significant drivers of dynamic complexity. For instance, bringing on new staff to handle a peak in workload may cause quality problems that require even more work to correct later on. DDP complexity seems to be increasing overall, for instance due to continuing introduction of new design issues and technologies, and increasingly fragmented disciplinary specialisation.
Third, considering iteration, it is well recognised in the literature that design and development are iterative in nature. Iteration can have numerous roles in the DDP, including: iteration to progress the design; iteration to correct problems or implement changes; and iteration to enable coordination within a process, or between a process and its context. Managing and exploiting iteration are critical to design and development on any scale, yet can be difficult in practice due to the many perspectives that are possible.
To summarise, these characteristics and related issues mean that companies and individual designers may not fully understand the processes by which they generate their designs. In consequence, the DDP is difficult to execute and manage effectively. Cost and schedule overruns are common. Because effective design and development is critical to many organisations' performance, this has motivated much research to better understand such processes and how they might be supported and improved.
Research has suggested that process models can help to address the challenges outlined above in several ways. For example, while large-scale design and development processes do involve novelty, they also involve routine sequences and structures that can be modelled. Consequently, a common view is that these processes "are systems and can be engineered", a task which can be facilitated by process models and process modelling. Process models may also help to align process participants and their mental models. They are, therefore, important enablers of coordination, defined by Malone and Crowston as the management of dependencies among activities. This becomes more important as complexity and innovation increase. Process models depicting best practice may be useful "to rationalise creative work, to reduce the likelihood of forgetting something important, to permit design to be taught and transferred, to facilitate planning, and to improve communication between disciplines involved in design". Models can also help to generate and communicate conceptual insights into the DDP. This is useful to researchers and educators, may inform practitioners, and may inspire the development of pragmatic support.
Although process models can, therefore, be helpful in understanding and handling the special characteristics of the DDP, those same characteristics make its modelling difficult. Despite extensive work undertaken since the 1950s, no single descriptive model is agreed to provide a satisfactory account of the design and development process. Indeed, this is probably not achievable. Similarly, in terms of prescriptive models developed to support or improve the DDP, there is arguably still "no silver bullet approach to achieve process improvement". This is again unsurprising considering the complexity of the topic and the many issues involved.