Key Points

• Taguchi’s quality loss function provides a measure of the overall loss to society when a product fails to meet its target functionality and reliability.
• Taguchi defines a signal-to-noise ratio (SNR) to measure the positive quality contribution from controllable or design factors versus the negative quality contribution from uncontrollable or noise factors.
• Taguchi Methods involve seven steps, beginning with a clear statement of the design problems and ending with a confirming statistical experiment showing how parameter choices enhance robustness
• An example from electrical circuit design was presented because it is much more similar to software design than mechanical design, where Taguchi Methods have found their largest application.
• An example from software design or product improvement was given, building on the previous example.
• A cause-and-effect or “fishbone” diagram was presented to guide fault analysis for the software example.
• Taguchi developed an earlier technique involving Latin squares or othogonal matrices to allow an evaluation on multiple parameters simultaneously.
• Othogonal matrices permit a multifactorial analysis that not only is far more efficient than a conventional “bottleneck” analysis but also allows the syudy of factor interactions.