<P> In 1946 Shainin was able to demonstrate to the Navy Bureau of Aeronautics that Lot Plot was more effective than 100% inspection . Following this, the Navy agreed to make Lot Plot a standard . Soon Lot Plot was adopted as a standard across many industries . </P> <P> Taking the advice of his friend and mentor Joseph M. Juran, Shainin turned to the world of consulting . In 1952 Shainin joined Rath & Strong, Inc., a management consulting firm based in Lexington, Massachusetts, holding the position of Senior Vice President . </P> <P> Shainin's development of the "Red X" concept originated from his association with Joseph Juran . In the 1940s Juran coined and popularized the notion of "the vital few and trivial many," also known as "The Pareto Principle," recognizing the uneven impact of problems on business performance to be the same phenomenon that Vilfredo Pareto had observed in respect to the distribution of wealth . As suggested by Juran, "I observed (as had many others before me) that quality defects are unequal in frequency, i.e., when a long list of defects was arranged in the order of frequency, a relative few of the defects accounted for the bulk of the defectiveness ." </P> <P> In the 1950s Shainin recognized that the Pareto principle could be applied effectively to the solving of variation problems . Shainin concluded that, amongst the thousands of variables that could cause a change in the value of an output, one cause - effect relationship had to be stronger than the others . Shainin called this primary cause the "Big Red X" and demonstrated that the cause can exist as an interaction among independent variables . The effect of the Red X is then magnified by the square - root - of - the - sum - of - the - squares law, thereby isolating the root cause . </P>

Who said quality defects are unequal in frequency