Local and National Estimates of the Prevalence of Problem Drug Use

As with any 'hidden' behaviour, it is not possible directly to enumerate the prevalence of Problem Drug Use and survey techniques are notoriously poor at providing credible estimates.  Using 'indirect' techniques, the Universities of Glasgow (Hay) and Manchester (Millar) were commissioned to provide annual estimates, for England and for each of the 149 Drug Action Team areas, of the prevalence of opiate and /or crack cocaine use /injecting over a three year period: 2004/05, 2005/06 and 2006/07 and have been further commissioned to provide estimates for 2007/08 and 2008/09.

Knowledge about the prevalence of Problem Drug Use is key to the development of effective policy in this area.  This work uses multi-sample capture-recapture (C-RC) to estimate prevalence at the local level.  For areas where it is not possible to obtain estimates based on C-RC, the Multiple Indicator Method is used to extrapolate from the available C-RC estimates.  National and local estimates for each of the first three study sweeps have been pulished by the Home Office and further information about the methods used can be found in: Hay et al., 2009; Hay et al., 2010.

• Hay, G., Gannon, M., MacDougall, J., Eastwood, C., Williams, K., Millar, T., 2009 Capture-recapture and anchored prevalence estimation of injecting drug users in England: national and regional estimates.  Statistical Methods in Medical Research. 18, 323-339.
• Hay, G., Gannon, M., MacDougall, J., Eastwood, C., Williams, K., Millar, T., 2010. Opiate and crack cocaine use: A new understanding of prevalence.  Drugs-Education Prevention and Policy. 17, 135-147.