How Representative Are Online Panels? Problems of Coverage and Selection and Possible Solutions
This chapter describes the most important problems of Internet surveys and online panels, explains how these problems can be overcome and discusses types of weighting procedures that can be applied to correct for lack of representativity. Collecting data using a survey is often a complex, costly, and time-consuming process. The rapid development of the Internet has led to another new type of data collection: computer-assisted Web interviewing. Such Internet surveys or online panels are almost always self-administered: Respondents visit a Web site and complete the questionnaire by filling in a form online. Internet surveys and online panels are often claimed to produce representative and therefore generalizable results, based on the application of advanced adjustment weighting procedures Self-selection or non-probability sampling occurs when researchers have no control over the sample selection mechanism. The effects of self-selection can be illustrated using an example related to the general elections in the Netherlands in 2006.