In the funnel video (volume 7 of the Deming Library), Deming talks about this...he describes the CEO of a company that took him to dinner once. The company made tubes for nuclear reactors. Deming looked at the charts...the data had been in control for two years, but sometimes still made defective tubes. Deming asked him what they did about those. The CEO told him "Our engineers never rest until they find the cause for every defective tube!" He told him they might as well study all the good ones, too. The same process made those...and would continue to make them until someone did something about the process. Deming finishes by saying, "pretty good thing to know...yes, knowledge...I call it Profound Knowledge. Pretty simple...stupidly simple...but RARE! UKNKNOWN! How could one consider himself in possession of a liberal education and not know these things?"