Among the roles of quality engineering, Genichi Taguchi cited relieving society of the need to predict, diagnose, and decide. To see what such a society would be like, a study of its existing problems was made. Following the recession referred to as the collapse of the bubble in the early 1990s, the Japanese economy has been running in low gear, but despite that, Japan has some 26000 long-lived businesses that have been operating for at least 100 years. The present study focused on the continuity of long-running Japanese corporations that have survived the major social upheavals of the past 100 years or more, and used their financial data and other data to construct a unit space for application of the Mahalanobis-Taguchi system. This unit space was then used in a study of Japanese corporate performance that revealed features of individual corporations.

Power harassment is the act of exceeding the proper bounds of authority in the workplace in order to inflict psychological or physical pain, but an objective definition of the proper bounds is difficult. A study was therefore made to see whether the proper bounds could be determined from a quantitative analysis of court decisions in cases of power harassment. The study was performed by extracting the actions of workers and their superiors from court cases, encoding them, and analyzing them by the standardized error root mean square method of the MT system, taking actions that had only a small effect on the other party to constitute the unit space. When the mean value of the worker's standardized error root mean square was plotted on the X-axis and the mean value of the superior's standardized error root mean square was plotted on the Y-axis, the plot showed agreement with the court results: cases in which only small compensation was awarded fell close to the balance line (y=x) that indicated the worker's actions and the superior's actions had about equal effect on the other party. This indicated the possibility of determining whether the superior's actions exceeded the proper bounds of authority by comparing the standardized error root mean square values of the superior's and worker's actions.