TASK-ANALYSIS FOR THE INVESTIGATION OF HUMAN ERROR IN SAFETY-CRITICALSOFTWARE-DESIGN - A CONVERGENT METHODS APPROACH

An investigation was conducted into sources of error within a safety-c ritical software design task. A number of convergent methods of task- and error-analysis were systematically applied: hierarchical task anal ysis (HTA), error log audit, error observation, work sample and labora tory experiment. HTA, which provided the framework for the deployment of subsequent methods, revealed possible weaknesses in the areas of ta sk automation and job organization. Application of other methods withi n this more circumscribed context focused on the impact of task and jo b design issues. The use of a convergent methods approach draws attent ion to the benefits and shortcomings of individual analysis methods, a nd illustrates the advantages of combining techniques to analyse compl ex problems. The features that these techniques should possess are hig hlighted.