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General population surveys (GPS)
Summary
Prevalence and patterns of drug use among the general population, measured by probabilistic surveys of the adult and school population, is one of five EMCDDA key indicators that assess the drugs situation and allow monitoring of progress towards EU and Member State drug policy targets. Data from general and school population drug surveys provides basic information to help to understand patterns of use, risk perceptions, social and health correlates, and consequences of use of illicit drugs and other psychoactive substances.
To achieve their real value in policy terms, surveys should be repeated at regular intervals with a similar methodology in order to allow identification of changes in prevalence and patterns of use, with sample sizes large enough to allow analysis of main sub-groups of the population. Member States should aim to conduct a series of consistent nationally representative surveys of the adult, and school populations, with standard age groups. At a minimum, data should be reported on period prevalence (lifetime, last year and last month) of different drugs. Surveys of good quality and sufficient sample size can give rich information on patterns of use in different subgroups, but may underestimate drug use in certain hidden and/or vulnerable populations, and complementary methods will be necessary (targeted surveys, indirect methods).
For surveys conducted among the adult population in households, the EMCDDA Handbook for surveys among the general population reviews and discusses key methodological issues regarding drug population surveys and provides guidelines for reporting of information to the EMCDDA. The Handbook provides a list of core items, called the European model questionnaire (EMQ), for inclusion in questionnaires of national surveys, or for reporting equivalent data from existing surveys. The EMQ can be used to collect data on the period prevalence of a range of drugs, as well as information on age of first use and frequency of use.
Methods for representative school surveys may be found in internationally coordinated school survey projects, and several national projects in Europe and the United States. School surveys typically collect data in classrooms through anonymous questionnaires on the use of alcohol and a range of drugs. In school populations, the target age of students surveyed can substantially influence the results.
More information on the GPS key indicator can be found in the 'GPS toolbox' on this page.
GPS toolbox
The GPS toobox provides access to a range of GPS-related material developed by the EMCDDA over the years. New resources will be added as they arrive.
Statistics
Key documents
- Overview of the GPS key indicator (7 pages, PDF)
This document provides an overview of the general population surveys indicator. It is written in an easy to understand manner and is intended for a wider readership. - GPS statistical methods and definitions
Part of the EMCDDA Statistical bulletin, this text provides a summary of the methods and definitions used in GPS and is primarily intended to assist in the interpretation of data. - GPS protocol: handbook for surveys on drug use among the general population (150 pages, PDF)
This protocol is the most detailed description available of the methodology used by the key indicator and is aimed at anyone planning, organising or executing a survey about drug use among the general population.
Other methodological resources
- Comparison of methods and resulting drug use prevalence estimates of health surveys versus drug surveys methods (PDF)
- Drug use: an overview of general population surveys in Europe
- Assistance to the EMCDDA for the analysis of drug profiles reports
- Methodological study to compare the effect of different methods of data collection on the prevalence of self-reported drug use in general population surveys (PDF)
- Technical implementation and update of the European Union databank on national population surveys on drug use and carrying out a joint analysis of data collected (PDF)
Data collection tools
Page last updated: Tuesday, 23 August 2011