who said quality defects are unequal in frequency
Dorian Shainin 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.[12]  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."[13]