Report 6 Methodological challenges

André van Gageldonk
Peter Reuter
Franz Trautmann

Abstract

This report describes problems encountered when comparing drug problems and policies over time and between countries. It identifies both conceptual and empirical elements of those limitations and covers examples in the fields of supply, demand and harm, as well as of efforts to reduce each.

Conceptual challenges include inconsistencies in definitions and operationalisations of concepts. Examples for this are concepts like ‘problem drug use’, drug-use related death and drug-related crime. There are also differences in defining categories for prevalence measurements, e.g. age groups. Concepts are also inconsistent over time in a given country e.g. as a result of changes in definitions. Finally, they are inconsistent across domains, e.g. some data may be available only at the household level, others at the individual level.

Empirical challenges cover in particular data scarcity and data quality. Many countries collect very little data and some data are very difficult to collect. The latter generally applies to collecting information on illicit phenomena as the production, trafficking and retail of illicit drugs. A direct comparison between countries is regularly hampered by the fact that certain data are not available for the same year. The quality of the data collection in most countries is poor.

Conceptual and empirical challenges may be related. Drug offences are one example for this. Countries use different definitions (e.g. sometimes including consumption, sometimes not) and data availability is limited.