Interventions to tackle the supply of drugs, are seen as standard components
of illicit drug policies and drug market-related administrative data, such as seizures,
price, purity and drug-related offending, are widely used for policy monitoring and
evaluation. However, these data are not primarily collected for this purpose, which
makes interpretation and analysis difficult. Examples of limitations of these data
sources include: the extent to which they reflect operational priorities rather than
impact on drug supply; question marks over the robustness of and consistency in data
collection methods; and issues around the timeliness of data availability.
Making sense of such data is therefore challenging and extreme care needs to be taken
when using it. Nevertheless, given the considerable resources invested in drug supply
reduction, understanding the impact of these interventions is essential, so improving the
quality of the data collected and expanding its scope should be a priority for those
seeking to understand or monitor drug markets and supply reduction. In addition to
highlighting some of the potential pitfalls in using supply indicators for policy
evaluation, this chapter presents some options for improvements based on the current
European Monitoring Centre for Drugs and Drug Addiction programme of work to
develop their supply-related monitoring and analysis. The conceptual framework
developed to underpin this work may have wider applications and has the potential to
provide a richer picture of drug markets, at both national and international levels, to aid
efforts to evaluate drug supply reduction policies.
Keywords: Drug policy, Drug supply indicators, Drug supply reduction, Evaluation, Monitoring.
