Planning on mistakes: An approach to incorporate error checking into the design process

Mistakes in the design process have been recognized as a major source of product quality loss. There are several methods currently used to identify and quantify these mistakes. However, these methods typically do not provide a useful context within which to quantitatively incorporate mistakes into the design process in a beneficial way. This paper presents an approach to determine when it is appropriate to perform error checking to eliminate a potential mistake. The proposed approach is intended to be used when time is a limited design resource and design goals are technically attainable. It is proposed that the cost of a mistake can be quantified as the amount of time a mistake adds or subtracts from the overall time required to achieve the design's objectives. To determine this, an optimization problem is formulated which minimizes time spent in the design process. In this optimization problem the design variables are the binary choice whether or not to perform an error check. The approach is demonstrated in two case studies, one a simple theoretical design problem and the other the design of an I-beam. The results of these case studies demonstrate the approach's effectiveness, and present several avenues for future work.