Abstract
The paper introduces a set of analyses of national surveys carried out in six countries—Finland, Sweden, Germany, Great Britain, France and Italy-as part of the European Comparative Alcohol Study (ECAS). The ECAS survey data were collected especially for the purpose of country comparisons. Therefore not only were the questions made as similar as possible in all six countries, but also the mode of data collection (telephone interviews), the sampling procedure (random sampling of telephone numbers), and the time of data collection (spring 2000). Despite all these efforts to ensure a high comparability, the crucial question of comparability of alcohol surveys in general, and of the ECAS six-country survey in particular, was raised at an early stage, since large differences were found among the six samples in response rates and in estimates of volume of drinking in relation to recorded per capita consumption (coverage rate). This paper pays attention to some of the validity problems in survey data in general and to the specific problems associated with this comparative survey approach in particular.