And why we may soon not be able to measure it at all.
Even in the so-called age of Big Data, there are consumer behaviors that researchers still have a difficult time tracking. Perhaps number one on that list? Heroin use. Unlike marijuana, alcohol, or tobacco users, who are generally forthcoming about the frequency and quantity of their consumption, users of heroin (as well as cocaine and methamphetamines, though neither of those drugs has a comparable death toll) are much less honest about their habits and therefore less likely to be captured in the U.S.'s most well-known voluntary survey on drug use, the National Survey on Drug Use and Health (NSDUH).
For as long as it's been around, the NSDUH has provided a pretty good picture of marijuana use in the U.S., and is a reliable source for annual stories about teens and pot (a perennial sticking point in the debate over marijuana legalization). But the NSDUH data on hard drug use seldom makes as big a splash. In a new report from the RAND Corporation, researchers suggest that one reason for this disparity may be that the NSDUH survey underestimates heroin use by an eye-boggling amount. "Estimates from the 2010 NSDUH suggest there were only about 60,000 daily and near daily heroin users in the United States," drug policy researchers Beau Kilmer and Jonathan Caulkins, both of the RAND Corporation, wrote in a recent editorial. "The real number is closer to 1 million."
The discrepancy is even more stark when comparing past-month use, which is how the NSDUH measures drug use:
Zoom out, and the difference between 60,000 and 900,000 daily users turns into a difference of 239,000 and 1.5 million monthly users. (To compare the figures yourself, here are NSDUH's monthly heroin numbers, and RAND's; table 2.4 in the RAND report explains how they came up with data for missing years.) "Our goal," Kilmer says of the comparison, "was to hit home that NSDUH is not the place to go for rich data about the cocaine/heroin/meth users who are largely driving those markets." (The RAND estimate does not include those reporting use of only 1-3 days a month.)
Kilmer and Caulkins came up with their much higher figures for heroin and hard-drug use by combining county-level treatment and mortality data with NSDUH data and a lesser known government survey called the Arrestee Drug Abuse Monitoring Program. Instead of calling people at home and asking them about their drug use, the ADAM survey questions arrestees when they're being booked and tests their urine. "ADAM goes where serious substance abuse is concentrated — among those entangled with the criminal justice system, specifically arrestees in booking facilities," Kilmer and Caulkins write. The survey also asks questions about street prices, as well as how and where drugs are bought. The data collected by the ADAM Program enabled RAND to put together a report looking at what Americans spent on drugs between 2000 and 2010.
In short, ADAM is a crucial tool for crafting hard-drug policy. Which is why researchers are alarmed that after being scaled back several times (including a brief shutdown between 2004 and 2006), funding for ADAM has completely run out. "Folks in the research world have known that this was coming," Kilmer writes in an email. "I wanted to use the attention around our new market report to highlight the importance of collecting information about hard drug users in non-treatment settings. ADAM was central to our estimates for cocaine, heroin, and meth."
Despite providing a wealth of information since the early 2000s, the budget for ADAM has slowly been chipped away. The survey was originally conducted in more than 35 counties, then 10, then five. The program disappeared completely between 2004 and 2006, but was revived by the Office of National Drug Control Policy in 2006. At its most expensive, ADAM cost $10 million a year.
Criminal justice researchers are worried. UCLA's Mark Kleiman called defunding ADAM the "dumbest move you’ll see this week," and Kilmer is alarmed not only about the loss of data ADAM has provided for years, but also the missed opportunities to expand the survey. ADAM "had a ton of potential," he says. "[T]here could have been rotating modules with detailed questions about health status, health care utilization, issues surrounding collateral consequences, etc."
That's not to say the NSDUH survey is useless. It really does tell us quite a bit about marijuana, tobacco, and alcohol use. But it clearly doesn't capture people who regularly use harder drugs—people who are more likely to lie when contacted by a government pollster, or people who won't get that contact at all, because they're indigent or locked up. At a time when policymakers at the local, state, and federal level are taking big steps to prevent heroin overdoses, the ADAM data seems more essential than ever.
"I’m thrilled Attorney General Eric Holder declared that heroin is an urgent public health crisis," Kilmer says. "However, if we don’t fund ADAM or something like it soon, we are going lose our ability to measure and track the abuse of heroin, cocaine, and meth."