Emergency decision making on offshore installations
The aim of this thesis was to examine the cognitive processes through which experienced Offshore Installation Managers (OIMs) make decisions during emergencies, and to determine whether they use a naturalistic or normative decision making strategy. That is, do they recognise the emergency as familiar and base decisions on condition-action rules serially generated (naturalistic), or do they need to concurrently compare and contrast options before selecting the best possible (normative). Emphasis was on the individual OIM's understanding of an emergency and the meaning he attached to the information or events taking place. The method employed to achieve this objective, was a Cognitive Task Analysis (CTA) based on triangulation principles, i.e. using multiple methods to examine the same research question and so enhance reliability and validity. The main findings of this thesis were: • Decision making in Safety Case (1992) identified offshore installation emergencies is primarily based on condition-action rules, or rule-based according to Rasmussen's (1983) model, not Standard Operating Procedures. • Decisions are serially generated. There is no evidence of option comparison. • The environment severely limits the number of options available to the OIM. • Decisions are predominantly made when one element of the present status of the incident changes. • Tactical decisions account for approximately 54% and operational decisions for 46% of the decisions made. • Nearly 50% of the decisions taken are instigated by other team members. • The majority of the time (86.8%) is spent on situation assessment. • The OIMs' situation awareness is limited to a maximum of eight interdependent problem categories. • Situation awareness comprises approximately four categories at any one point. • Risk and time pressure are the two major factors contributing to incident assessment. • There are individual differences in decision making style and situation awareness.