In market research, the question-and-answer business is not so simple, and the ease of furnishing answers in everyday life may involve dangerous pitfalls. In social intercourse, it is most likely that what is important for our respondent is important also for us who have made the inquiry. In market research interviews, we cannot rely upon this good fortune. The purpose of our why questions is to discover all of those factors which determine the purchases of a certain group of people; or, to put it more exactly in anticipation of a later part of this paper, we want to know all the determinants of a certain sort. Such knowledge should permit us to increase our future efficiency in this field by providing a more complete and accurate basis for anticipating demand factors of the market.