Web-based questionnaires and the mode effect - An evaluation based on completion rates and data contents of near-identical questionnaires delivered in different modes

Most methodological evaluations of web-based questionnaires have focused on the issues of sampling and response rates. Some have considered the issues of privacy and ethics. Relatively few have addressed the question of whether people provide different information depending on the mode of questionnaire delivery. This article contributes to this relatively overlooked aspect of the evaluation of web surveys. It presents initial findings from a survey that was designed to enable near-identical groups to respond to near-identical questionnaires delivered in different modes. Web-based questionnaires and paper-based questionnaires, used as part of a school-based study of young people's health-related behavior, are compared in terms of (a) completion rates and (b) data contents. Issues surrounding the quality of data and the reliability of webbased questionnaires are discussed. It is concluded that, on the basis of the quantitative data from this survey, there is little evidence of a mode effect linked to web-based questionnaires.