Lessons from Stockwell: How a combined approach to accident analysis can inform system design

This paper takes a fresh look at how human factors' modelling techniques can inform the design of systems and organisations in the light of accidents, errors, or undesirable outcomes. Considering incidents at both an organisational and individual level, the approach models the flowofinformation and orders within and system and considers the impact on task performance. The shooting of Jean Charles de Menezes at Stockwell Underground station is used as a case study to illustrate the technique. Using an approach based upon AcciMaps, the salient findings of a number of published reports are summarised in a single representation. The model captures both latent conditions and active failures, ranging from component failures to overarching bureaucratic or political issues. The paper also considers how the information available to those at the 'sharp-end' has the potential to impact perception and task performance. Based upon these findings, changes to the organisational structure are proposed, to provide those at the sharp end with the information, strategic understanding and authority to keep pace with dynamic situations.