https://www.sciencedaily.com/releases/2018/07/180723132247.htm > It had long been apparent to Brady West, an expert on survey methodology at the University of Michigan, Ann Arbor, that the benefits of survey data coexisted with a lack of training in how to interpret them correctly, especially when it came to secondary analyses -- researchers reanalyzing survey data that had been collected by a previous study. > "In my consulting work for organizations and businesses, people would come in and say, 'Well, here's my estimate of how often something occurs in a population,' such as the rate of a disease or the preferences for a political party. And they'd want to know how to interpret that. I would respond, 'Have you accounted for weighting in the survey data you're using -- or, did you account for the sample design?' And I would say, probably 90 percent of the time, they'd look at me and have no idea what I was talking about. They had never learned about the fundamental principles of working with survey data in their standard Intro to Stats classes."