| "Do they do anything similar to correct for lying" There is an entire literature on the validity of self-reported drug use that they take into account. For example, there is a phenomenon called recanting, where someone will admit to using a drug one year and then deny it in future years. They correct for this by ignoring when someone recants if they have already admitted to using the drug on at least two previous surveys. (Which would be administered at least two years apart.) What they found was that the people most likely to recant were the ones who got jobs where they would now be fired for admitting drug use. For example, cops recanted drug use after previously admitting to it at twice the rate of the general public. So that's how they made the decision to discount recanting for people who had already admitted to drug use twice or more times. As for people who try to lie and claim they are taking drugs that they haven't been, this is corrected for by asking about the same drug multiple times in different ways. I think they may also salt the questions by asking about drugs that don't exist. You can obviously read all about the methodology of Monitoring the Future by downloading it, and here is an enormous PDF with tons of studies on the validity of self-reported drug use in general: http://archives.drugabuse.gov/pdf/monographs/monograph167/do... All in all the methods they are using seem fairly accurate. It would definitely be a little higher if they corrected for more stuff, so for example when they say that 82% of Americans have used marijuana, it's actually probably closer to 85 or 86% when you correct for additional things that they haven't. |