Sources of Error in the Design Process

This paper reports on an investigation into the causes of error in the design process based on a series of case studies in three companies. An initial study attempted to identify the points of occurrence of error in the case studies based on formal process models of the design activities. However, it was found to be difficult, if not impossible, to make a clear identification of a point of introduction of error in any of the case studies. In general, there was no single error source, but instead there was an accumulation of a number of contributory factors that when combined led to the error situation. Furthermore, it was generally not process issues that led to error but human factors. The paper identifies four categories of error inducing circumstance: unrecognised change of circumstances; lack of design effort; lack of integration of information and want of knowledge. Overall, it is asserted that the underlying issue is one of uncertainty handling and risk management.