Characterizing failures in design activity

Abstract A study was conducted of errors made during the design process in an organization that designed complex, hazardous installations. About 90 errors were investigated, and all were represented individually by a causal tree. Each case was categorized according to the particular activity that was implicated in the error in order to find out how error was distributed over the design process. The more fundamental causes of these errors—those without more basic causes in the causal trees—were compared, and an attempt was made to identify their instrumental elements. These instrumental elements included properties of the design task (such as idiosyncrasy, uncertainty and redundancy), properties of the inferences designers drew from their experience, properties of the organizational environment and properties of the models used by designers.