Evaluation of the Human Factors Analysis and Classification System as a predictive model


The Human Factors Analysis and Classification System (HFACS) is a hierarchical taxonomy that describes the human factors that contribute to an aviation accident or incident that is based on a chain of- events theory of accident causation and was derived from Reason's (1990) accident model.

The objectives of this exploratory study were to identify relationships between the factors of the HFACS taxonomy and to assess the usefulness of HFACS as a predictive tool. The associations found in this study may assist investigators in looking for associated factors when contributing factors are found. Also, when using the HFACS taxonomy to identify areas for intervention, the relationships found may also guide intervention in associated areas for a holistic, systems approach to improvement.

This exploratory study found a number of strong positive relationships between factors at different levels of the model. However, based on the amount of variation explained by the logistical regression statistical models, it appears that HFACS is a more effective predictive framework when used to predict unsafe acts than when used to predict higher levels within the taxonomy.

The Australian Transport Safety Bureau (ATSB) formalised the concept of outside influences and added five factors within this grouping to the HFACS model in this study. The outside influences factors proved to be important additions to the HFACS model as they were associated with factors at all levels of the HFACS taxonomy.

The results have also shown that it is not always the case that higher-level factors predict only the lower-level factors directly below them. For example, inadequate supervision predicted precondition for unsafe acts, such as adverse mental states and crew resource management issues, as well as skill-based errors (two levels down).

Type: Research and Analysis Report
Investigation number: AR-2008-036
Author(s): Inglis, M., Smithson, M. J., Cheng, K., Stanton, D. R., Godley, S. T.
Publication date: 10 December 2010
ISBN: 978-1-74251-120-7
Publication number: NOV10/ATSB151
Last update 26 June 2017
Download complete document - Evaluation of the Human Factors Analysis and Classification System as a predictive model
Download complete document
[ Download PDF: 2.22MB]