A new questionnaire for the repeat of the first stage of the European Community Respiratory Health Survey: a pilot study

In the early 1990s a multicentre survey on asthma was performed on the youn g adult population (European Community Respiratory Health Survey - ECRHS). This study is to be repeated in order to estimate changes in the prevalence of asthma-like symptoms during the last decade and to assess the social an d economic costs of the disease and their variations among countries. The self-administered questionnaire devised for this purpose is a two-page questionnaire. The first page contains the same items as those used in the first survey with four additional questions related to: 1) the frequency an d severity of asthma attacks; 2) the presence of chronic bronchitis; 3) smo king habits; and 4) a visual analogue scale assessing perception of outdoor pollution, The second page aims to collect information regarding the direc t and indirect costs of asthma, The Influence of the length of the question naire on the response rate was assessed in a pilot study in Italy. Two rand om samples of 150 subjects received either the one-page questionnaire (firs t page) or the two-page questionnaire, The response rate was compared with that obtained from the first postal wave in the 1991-1992 survey. Although the response rate was unchanged when using the one-page questionna ire (45% versus 45%), it decreased by 7% when the two-page questionnaire wa s used (38% versus 45%). On the basis of these results, no problem should arise if four more questio ns are added to the one-page questionnaire. The slight reduction in the res ponse rate of the two-page questionnaire is worrying but could be corrected by the use of telephone interviews.