The Use of the Dynamic Flowgraph Methodology in Modeling Human Performance and Team Effects

Abstract

In current probabilistic safety assessments (PSAs), the modeling of teamwork in the analysis of complex system operation is limited in many respects. One major limitation is that the operating team has been modeled as one operator performing an isolated set of tasks, rather than as a group of individuals working in an interactive environment. Studies conducted by behavioral scientists addressing team effects, on the other hand, are mostly qualitative and do not include system hardware failures. In this paper, we present the Dynamic Flowgraph Methodology (DFM) as an approach to model the operating team. DFM provides a tool with which the performance of individuals in the team and the system hardware can be modeled in an integrated fashion using a clear graphic representation of the causal relationships between physical variables and human characteristics. The advantages of using DFM models include its dynamic representation of the system operation and its modular nature, through which human and team characteristics can be modeled with much flexibility.