The ESPAD project was started due to the lack of comparable data on substance use among European teenagers. In order to collect such data, a common methodological protocol was established in the early 1990s, including a master questionnaire. For pragmatic reasons the survey is conducted among students in class rooms.

The overall aim of the ESPAD Project is to collect comparable data on substance use among 15–16 year old students in as many European countries as possible. The most important objectives in the long run are to monitor trends, and to compare trends between countries and between groups of countries. In order to do so, the surveys are repeated every four years, with 1995 as the starting point.

Students’ participation is voluntary and totally anonymous and no results are presented for individuals or single classes. Apart from using a common questionnaire on a commonly defined target population also data collection period, field work practices as well as capture, cleaning, delivery and analyses of the data are carried out in standardised fashion.