Validating estimates of problematic drug use in England

Area of Science:

• Public Health
• Epidemiology
• Drug Policy Research

Background:

• UK government drug abuse initiatives depend on illicit drug user estimates.
• The accuracy of these estimates has not been previously validated.
• This study addresses the validity of problematic drug use (PDU) and injecting drug use (IDU) estimates.

Purpose of the Study:

• To assess the face validity of PDU and injecting drug use (IDU) estimates in England for 2001.
• To evaluate the accuracy of estimates used for UK government drug abuse expenditure.
• To determine the reliability of the Multiple Indicator Method (MIM) for drug user estimation.

Main Methods:

• A questionnaire-based study involving 149 English Drug Action Teams (DATs).
• DATs were surveyed to evaluate the face validity of MIM-derived PDU and IDU estimates.
• Analysis of response rates and potential selection bias.

Main Results:

• A 60% response rate was achieved with no indication of selection bias.
• 64% of responding DATs found PDU estimates acceptable; 27% considered them too low, 9% too high.
• Regarding IDU estimates, 52% were deemed acceptable, while 44% were considered too low and 3% too high.

Conclusions:

• This is the first UK study to assess the validity of problematic and injecting drug use estimates.
• The findings underscore the importance of considering both criterion and face validity in drug user estimation.
• Results indicate potential inaccuracies in current drug user estimates, impacting public health resource allocation.