Yes, I've been doing market research for 25 years. I know how sampling works. Suffice to say, JD Power makes sure its sampling frame passes established market research guidelines. Or do we really need to question that well-established, professional entities know how to do their job? PS: then again, so-called "industry experts" were telling us to buy homes right before the housing collapse... From a research and statistical perspective, JD Power's key weakness is not in its sampling or questionnaire design, but in RANKING survey results that are NOT statistically significant. For instance, saying that Lexus with 95 pp100 ranks first and Porsche with 96 pp100 ranks 2nd is incorrect, because they cannot ascertain that 95 is, in fact, better than 96, once you allow for statistical significance. And to then go and sell advertising rights based on this made-up distinction only aggravates this problem.