Foremost is the principle that the purpose of consumer research is to understand the customer's needs and wishes, and thus design product and service that will provide better living for him in the future. A second principle is that no one can guess the future loss of business from a dissatisfied customer.
W. Edwards DemingOne need not be eminent in any part of profound knowledge in order to understand it and to apply it. The various segments of the system of profound knowledge cannot be separated. They interact with each other. For example knowledge about psychology is incomplete without knowledge of variation.
W. Edwards Deming