Taguchi proposed that performance degradation can be measured as a deviation from some target value as a quadratic
quality loss function (fig.
Clearly, the
quality loss function is a way to show the economic value of reducing variability and staying closer to the target value.
Since I believe that cost is more important than quality, I have devised the
Quality Loss Function (QLF), a quadratic equation that allows engineers to evaluate quality in financial terms: The cost of reworking or scrapping a product, the cost of warranty, or the cost of such intangibles as customer inconvenience or goodwill increases by the square of the deviation of the product from its target function.
Quality Loss Function is useful for the last enumerated scope.
[9.] Roslund, J.L., "Evaluating management objectives with the
quality loss function", Quality Progress, August 1989, pp.
In the example of the power supply network, one might need to apply different evaluation criteria (such as the
quality loss function) to determine the optimal setting for the system parameters.
Quality Loss Function, defined by Genichi Taguchi, allows quantifying the consequences for manufacturer and customer regarding product quality level in financial terms.