Pitfalls of Quantitative Surveys Online

With the development of the Internet in the last two decades, its use in all phases of field survey is growing very quickly. Indeed, it reduces costs while allowing exploration of relatively large files and enables effective use of a variety of research tools. The academic research is more reserved towards developing online surveys. Demands on the quality of data are the main cause; Internet surveys do not meet them and thus do not allow drawing objective conclusion about the populations surveyed.Unqualified use of the Internet may significantly influence data and information obtained from their analysis. The problematic definition of the population that is under investigation may result in a fault of its coverage. Its existence can be shown, for example, on a confrontation of the total and Internet population of the Czech Republic, the total and Internet population of the Czech households, etc. Representation of the population through an online panel may cause bias, depending on how the panel is created. A relatively new source of error in an online survey is the existence of "professional" respondents.The sampling method from a population or an online panel can lead to the emergence of such a sample that is not representative and does not allow inference to the population at all, or only in a very limited way. Even probability sampling, however, can be problematic if it is affected by a higher rate of non-responses. The aim of this paper is to summarise the possible sources of bias associated with any sample survey, but also to draw attention to those that are relatively new and are associated with the implementation of just quantitative surveys online.