276 Int. J. Risk Assessment and Management, Vol. 2, Nos. 3/4, 2001 Copyright © 2001 Inderscience Enterprises Ltd. On systems analysis and performance assessment in complex, high-risk work environments Arne Worm National Defence College, Department of Operational Studies, PO Box 27805, SE-115 93 Stockholm, Sweden E-mail: TRIDENT@dof.se Abstract: In this paper we outline our work on analysis, evaluation and assessment of military and emergency response units performing complex, high-stake tactical operations. We pursued a broad research approach and adopted a combined theorist’s and practitioner’s perspective to discover novel and effective ways to accomplish this objective. Experiences from this work made it possible to develop theories, methods and tools for modelling, analysis and accident prevention in precarious time-critical systems control in military missions and emergency response operations. Critical skills of individual operators and teams, mission resource management, and overall unit performance were the primary fields of study. We performed case studies, field studies, and experiments using a combined control theory, Naturalistic Decision Making and Cognitive Systems Engineering framework. We also tested these concepts in several simulated tactical operations, and finally, validated the concepts in a number of full-scale exercises. Keywords: Methodologies; tactical operations; decision-making; command and control; emergency management; system design; incident analysis; performance assessment. Reference to this paper should be made as follows: Worm, A. (2001) ‘On systems analysis and performance assessment in complex, high-risk work environments’ , Int. J. Risk Assessment and Management, Vol. 2, Nos. 3/4, pp.276–287. Biographical notes: Lieutenant Colonel Arne Worm is an officer and researcher in the Swedish Armed Forces, currently assigned to a research position at the National Defence College in Stockholm. He holds an MSc in Mechanical Engineering and Computerized Automation, a Licentiate degree in Engineering and Human-Machine Interaction and a PhD in joint Human- Systems Engineering. His main research interest is tactical real time interaction in distributed environments, which includes command, control, communications and intelligence in military operations, air traffic control and emergency management. His core research areas are computerized automation, human-machine interaction, control theory, mathematical modelling, cybernetics, cognitive systems engineering, distributed team decision making and team training.