Heroin use cannot be measured adequately with a general population survey.

GPS, even those as strong as NSDUH, are doomed by their nature to estimate poorly a rare and stigmatized behavior concentrated in a hard-to-track population. Although many European nations avoid reliance upon these surveys, many others follow the US model. Better estimation requires models that draw upon a variety of data sources, including GPS, to provide credible estimates. Recent methodological developments in selected countries can provide guidance. Journals should require researchers to critically assess the soundness of GPS estimates for any stigmatized drug-related behaviors with low prevalence rates.