ABSTRACT
Working systems rely on their intrinsic variability (Vidal, 1985). For example, in systems like those found in the construction industry, large oil refineries, health care, and aircraft design, variability is the central regency of the process control. Therefore, managing variability is the core of work performance, and is thus directly related to its success. In other words, one should shift the old “keep control” motto to a new “keep under control” motto.
