Robust Quality

Product "robustness" is a function of good design. Still, most traditional quality programs concentrate on the factory. Zero Defects says that when parts come in within tolerances, the product will be fine. But parts just within tolerances have no advantage over those that just miss; it is better to miss a target consistently than to hit it haphazardly. Robust products maximize "signal-to-noise" ratios of component parts. Product designers can maximize these ratios by running experiments according to orthogonal arrays, which reckon the average effect of each variation on all other variations.