Introduction

Why do systems fail? Many researchers have investigated this question in areas such as nuclear power plants, air flight operations, or manufacturing plants. The approach to investigate failures in an industry-specific context seems to be useful, since causes may be dependent on parameters, which may differ between industries. A reason for selecting the industries above as fields of research is their complexity, which makes the identification of causes of failures and the correct evaluation of critical situations more difficult (Perrow 1999). As another example, Dörner (1992) names the criticality of these systems, which means that accidents might cause death and/or severe harm to many people. Hence, on the one hand, causes of failures may differ from industry to industry, and on the other hand, the negative effects of errors differ in form and magnitude.