The use of structural equation modeling to describe the effect of operator functional state on air-to-air engagement outcomes

Abstract: Computational evidence of the operative usefulness of a new system is crucial in large system development processes concerning billions of euros or dollars. Although it is obvious that the human often is the most important and critical component of many systems, it has often been hard for Human Factors researchers to express human aspects in a computational and strict way. The thesis describes, through data based statistical modeling, how the concepts or constructs of sensor effectiveness, usability of information, mental workload, situation awareness and teamwork relates to each other and to the operative performance in a fourship of fighter pilots. Through the use of structural equation modeling, ad modum LISREL, a statistical model that describes how the operators’ functional state mediates the effects between technical system oriented variables, was developed.The constructs used in the modeling process have received widespread scientific and operational attention. They have also been identified as multi-dimensional. Many different ways of measuring them have been developed in the scientific community, and the thesis focuses on the next step, i.e. how do these higher order constructs relate to each other in something as multi-dimensional as human activity in real situations?A comprehensive human factors related dataset was collected in a large simulation based acquisition study that examined the requirements and properties of aircraft radar systems. The dataset contains 308 simulated engagements with data from four pilots each, i.e. 1232 cases in a database with 24 variables, generated by 37 pilots. The collected data and the resulting models thus summarizes more than 700 hours of experienced pilots’ complex behavior in an operationally valid environment, and in a way that is of theoretical interest as well as of importance in system development processes. The data thus comes from a real world study of complex processes in a dynamic context, although from a simulator. The thesis is a case example of modern ecologically valid experimental psychology. The data collection does not represent a classical experimental setup, but instead demonstrates methodological needs and considerations for human factors practitioners when working in system development studies. The fact that parts of the used data are classified has not affected the models and scientific conclusions, although the practical findings have been partly circumscribed in the presentation.As a result of the statistical modeling effort, a structural equation model of how the chosen constructs relate to each other, and mediate effects between technical measures by a model of the operator, is proposed. Simplicity of the model was the goal, and based on former experiences and findings, a simplex structure was hypothesized. The final model shows that the covariances between the 24 measures can be explained by a quasi-simplex structure of seven factors.