The practical application of design risk assessment models

Abstract

This paper describes three case studies of the application of quantitative design risk assessment methods in practice. The studies arose out of a survey of risk practice in design which showed that leading edge companies use quantitative methods of risk assessment in assessing both project risk, which may be defined as the risk to cost and time-scale, and technical risk, which may be defined as the risk that the designed artefact will not meet its functional requirements. The first case study concerns a coastal defence programme and is primarily concerned with technical risk. The second study is concerned with the installation of a replacement bridge and is primarily concerned with project risk. The final study describes an aerospace engine design programme that involved both technical and project risks The paper first presents a generic overview of the risk management process and then describes, for each of the three study domains, how risk is identified, how risk assessment is carried out, including prioritization and uncertainty modelling, what risk treatment steps are undertaken and how risks are monitored. Outcomes in the three studies are shown to be a whole-life cost-benefit uncertainty model for assessing design alternatives, a method for incorporating uncertainty into task criticality as well as task duration in the activity network for a design project and a method for aggregating uncertainty in design attributes over the basic product model.