Decision and commission errors-from identification to quantification issues

The issue of errors of commissions (EOCs) is a focus of recent research in human reliability analysis (HRA). A key problem has been to develop efficient schemes for identifying risk-significant EOC situations. The results now emerging are promising in terms of the identification problem. As long as quantification remains problematic, however, the question of quantitative risk significance can be answered only partially. This paper discusses some conclusions that can be drawn from the analysis and quantification of scenarios identified in a pilot study of EOCs, highlighting problem areas for current HRA quantification methods. Because the probabilities of EOCs are expected to depend strongly on the specific features of each situation, defining a set of risk factors and of mitigating factors, understanding the interactions among these, and developing probability estimates for a library of anchor situations appear to be key elements of future quantification.