Selected Problems of Quality Assessment in Internet Surveys – a Statistical Perspective

The paper presents selected problems related to the quality assessment from the statistical perspective of survey data based on Internet sources. Internet access is consequently expanding all over the world. In parallel with the running development of other new technologies, it is pervading daily life and business activities more and more. It also has influenced surveys practice to a large extent as a research tool for collecting both primary and secondary data, and it also challenges surveys to research the Internet population. Moreover, as the Internet and its entities are able to register all activities that are performed on the web, issues related to big data and organic data processing as well as their applications arise. As a result of decreasing response rates and increasing survey costs, Internet data collection is constantly growing. Due to many advantages, Internet surveys are used widely and this process seems to be inevitable. However, it needs to be emphasised that Internet surveys are developing in practice faster than the methodology in this area. Hence, a lot of problems can be identified, especially when considering the quality of data based on Internet sources. The following issues are discussed as the most far-reaching in the prism of statistical survey methodology: determination of the sampling frame, self-selection and related estimates bias, as well as under/over-coverage.