Well, they can assign reported history of drug use correctly. Do they do anything similar to correct for lying, or just label their data as "self-reports of drug use"?
"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:
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.
I really don't think you can adjust away the teenage propensity to lie on these sorts of things. If there's one thing students in the US are taught effectively, it's how to game multiple choice tests. Throwing in trick questions isn't going to do much, especially for your AP-track students.
"I really don't think you can adjust away the teenage propensity to lie on these sorts of things."
The research seems to show that the self-reported responses are pretty accurate. For example, the number of people who reported using LSD basically went to zero right after the Pickard bust in 2003, when pretty much the entire US production got shut down. This means that if there are people lying about taking drugs they haven't been taking, it can't really be much than a couple tenths of a percent.
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.