The phrase "constancy of purpose" captured, for Deming, what quality is all about in organizations. Plenty of companies have mission statements, but few seem infused with a sense of mission. Jeffrey Liker's book "The Toyota Way" makes clear that what makes that firm unique among its competitors is not a set of superior production tools. Rather, at all levels of the organization, there is an abiding belief in a production system that relentlessly seeks incremental improvements. The "lean" organization eliminates all that does not contribute to quality for the customer--whether the customer is internal (the next group of people in the production process) or external (the purchaser of the end product).
My review of individuals who are widely considered to be great within their fields--athletics, science, arts, leadership--finds that they are lean in the same way. They find a field that captures their imagination and interest, and they tinker at it and work with it until they reach a high level of mastery. This constancy of purpose is driven by a love for the effort itself: a chess grandmaster or Olympic athlete seeks out opportunities to meet challenges and become the best they can be. Taxing the production system and occasionally shutting down the production line is essential to Toyota's success. Until you test the limits of your system, you can't know where the weaknesses are. The highly successful individual is one who craves such tests. This is what Nietzsche meant when he said, "Under peaceful conditions, the warlike man turns on himself."
The psychologist Abraham Maslow made a crucial distinction between individuals who are driven by needs and those who pursue values. One is engaged in the elimination of deficit states; the other seeks to accomplish positive ends in their own right. He believed that, once basic needs were met, individuals would be free to actualize their greatest potentials. Yet it is not that simple. Many people have their basic needs more than met and yet display little constancy of purpose in their own lives.
Ed Seykota noted that good traders have talent, but--with great traders--the talent has them. So it is in any field. Constancy of purpose comes from the capacity to become absorbed in one's pursuits, to find them inherently challenging and meaningful, and to allow oneself to become a vehicle through which talents and skills are expressed.
That requires finding one's productive niche. Not a job, not a career, but a calling. How many traders fail to succeed at their work--how many people fail to succeed in life--because they have not found that niche that fits their talents, skills, and interests? Constancy of purpose is a natural outgrowth of finding a niche: When you're doing what you are meant to be doing, it is difficult to veer from the path of quality.