Abstract:

The title of this paper should not raise too many hopes: our experience of this problem, despite the large number of investigations made, is not varied, comprehensive or long enough to enable a final answer to a question where many factors are involved. The paper's aim is thus no more than to add a further contribution to the sum of discussion already published, by quoting the most significant elements of practical surveys performed and attempting to draw the right conclusions from them. In the interests of clarity, our analysis of the differences and common features as between interview and mail questionnaires is broken down by reference to the two main stages in the survey process: - the preliminary contact between the interview prospect and the research company; - processing of the questionnaire itself.