Current research areas are:
   Medical Decision Support
   System Safety and Risk

System Safety and Risk

Historically, risk assessment in safety systems has accepted models derived from knowledge; the use of data is however less common. At the same time, there is a need to expand the scope of risk models in two ways: first, to encompass the organisational and human aspects of complex (socio-technical) systems; second, to be able to condition risk estimates on specific or local conditions, to construct a risk profile (by location or installation) rather than merely an overall aggregate.

Risk Models

Working with George Bearfield and others at RSSB, I have proposed ways to extend fault and event trees to create risk profile. I have applied this to models of both high severity, low frequency incidents and to models of lower severity, high frequency incidents, where the model can be partly learnt from data.  

Selected Papers

Bearfield, George; Holloway, Anna; Marsh, William; Change and safety: decision-making from data Proceedings of the Institution of Mechanical Engineers, Part F: Journal of rail and rapid transit, vol 227, no 6, p704-714, 2013

Marsh, DWR; Bearfield, G; Generalizing event trees using Bayesian networks Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability, vol 222, no 2, p105-114, 2008

Marsh, William; Bearfield, George; Representing parameterised fault trees using Bayesian networks Computer Safety, Reliability, and Security, p120-133, 2007

Hazards in Complex Systems

Hazards are a central idea in practical risk analysis and in complex systems it is naturally desirable to structure the analysis by subsystems and to reuse elements of a hazard analysis from related systems. Working with Rune Winther at COWI, I have reviewed the confusion that surrounds hazards in complex systems and proposed a structure for coherent hazards in complex systems.

Selected Papers

R. Winther, W. Marsh, Hazards, accidents and events—a land of confusing terms, ESREL 2013, Safety, Reliability and Risk Analysis: Beyond the Horizon