Survey statistics deals with the analysis of interesting characteristics of finite populations on the basis of statistical surveys. This concerns empirical researchers and users in various fields such as empirical social and economic research, market and opinion research and official statistics. The internal research focus "Survey Statistics - Data Quality in Statistical Surveys" covers the more theoretical concepts of the sampling theory and the more practical issues of the survey methodology in sample and population surveys. These topics include, for example, questions about the quality of sampling designs, the calculation of sampling errors and the consideration of non-sampling errors or alternative questioning designs with respect to the protection of respondents? privacy. Research projects conducted at the Department of Applied Statistics in this respect include the EU-project ?DACSEIS? in the field of official statistics, an in-depth study on the PISA survey in the field of educational research, the social sciences' PUMA-project, and projects to estimate the degree of coverage of network operators in Austria.