Forbes – Jacob Sullum -March 10, 2014
“According to the National Survey on Drug Use and Health (NSDUH), about 620,000 Americans used heroin in 2010. But according to a new report commissioned by the Office of National Drug Control Policy, something like 1.5 million Americans were “chronic heroin users” that year. That group includes anyone who has consumed heroin on four or more days in the previous month.
This dramatic discrepancy results from the report’s attempt to count heroin users missed by NSDUH, whether because they did not respond honestly, because they did not respond at all, or because they were not part of the household population sampled by the survey. To adjust for such undercounting, Beau Kilmer and eight other drug policy analysts at the RAND Corporation rely mainly on data from the Arrestee Drug Abuse Monitoring Program (ADAM), which includes urinalysis as well as a survey. Because it focuses on arrestees, ADAM is more likely than NSDUH to identify heavy drug users. But its sample, unlike NSDUH’s, is not nationally representative, so Kilmer and his colleagues must perform a series of calculations to convert ADAM numbers into total male arrestees testing postive for heroin and divide those users by frequency of use. Then they add estimates for men who were not arrested as well as for women and teenagers, based partly on NSDUH and information about overdoses, emergency room episodes, and treatment admissions.
The RAND researchers convert their estimate of heroin users into estimates of total consumption and spending. They use similar methods to estimate the size of the cocaine, methamphetamine, and marijuana markets. In the case of marijuana, a drug for which NSDUH seems to be a better guide, Kilmer et al. rely mainly on numbers from that survey, inflated by 25 percent and supplemented by ADAM data for respondents with criminal records. It is an impressive, headache-inducing feat, but one that is subject to “great uncertainty” because of the assumptions involved and the limits of the data, as the authors repeatedly acknowledge. “In many cases,” they say, “the extent of the uncertainty cannot be bounded or quantified.” They do not really know, for example, “the extent to which one can trust arrestees’ self-reports about their spending on illegal drugs” or “how to extrapolate just ten urban areas’ arrest records to the country as a whole.” Click the link below to read the entire article…