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Youth and the schools population — statistical methods and definitions

Data presented in the schools survey tables are derived mainly from the ESPAD schools survey project and the HBSC (WHO) Schools survey — Health behaviour in school-aged children. Participation in both surveys, each conducted every four years, has grown in each round and now includes most EU Member States and non-EU countries.. In addition, annual, or biannual national schools surveys are conducted in Spain, Italy, Portugal and Sweden and regional surveys are conducted in the UK and Belgium.

The international comparability of the ESPAD schools survey is based on nationally representative samples of school classes with the goal of having at least 2 400 participating students from the target group, and by standardising the target age group (between 15–16 years), the questionnaire, data collection in schools, assurance of anonymity and the time of year that data collection takes place. Caution is recommended regarding some data in specific countries: comments on these are found in the methodological information sections and in published reports — ESPAD (The European School Survey Project on Alcohol and Other Drugs) 1995, 1999, and 2003. 2007 and 2011 by The Swedish Council for Information on Alcohol and Other Drugs (CAN), EMCDDA and the Council of Europe (Pompidou Group). See an EMCDDA produced multilingual summary of the 2007 and 2011 ESPAD surveys for further information.

The HBSC (WHO) Health behaviour in school-aged children included, for the first time in the 2001/2002 surveys, questions about cannabis use. International comparability is based on standardisation by target age group (mean age, 15.5), cluster sampling methods with the goal of more than 1 500 participating students from the target group, questions about cannabis based on the ESPAD survey questionnaire, data collection in the schools, and assurance of anonymity. As with ESPAD, caution is recommended regarding some data in specific countries (see descriptions of the studies and publications).

National schools surveys conducted in Belgium, Spain, Italy, Portugal, Slovakia, Sweden and the UK are largely comparable with ESPAD and HBSC surveys in terms of sampling, 15/16-year-old age groups, the questionnaire, data collection in schools, and assurance of anonymity. Overall, the comparisons made between ESPAD data and other school surveys (in three countries — Norway, Sweden and the Netherlands — as well as comparisons between ESPAD and the HBSC surveys) show very similar prevalence figures. In other countries, differences in methods for achieving prevalence estimates mean that caution is necessary with regard to making direct comparisons between some of these surveys.   However, continued and strengthened collaboration with the EMCDDA and between national and international projects is helping to facilitate comparable methods and definitions.

About the EMCDDA

The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) is the reference point on drugs and drug addiction information in Europe. Inaugurated in Lisbon in 1995, it is one of the EU's decentralised agencies. Read more >>

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Page last updated: Thursday, 16 May 2013