Abstract
In Spring 2020 the World Health Organization (WHO) has published guidelines for population surveys which can deliver baseline data for health policy decisions in pandemic situations. The realization of the guidelines is by no means trivial. In this essay we describe the challenges of a statistical assessment of the Corona Pandemic. In the first part we treat the extent of hidden cases in the registration of Corona infections, the measurement of infection histories outside the clinical sector, the measurement of risk factors and finally the measurement of temporal and regional changes of the intensity of the pandemic. We discuss several possibilities but also limitations of surveys statistics to cope with the manifold challenges by a proper survey concept and design of a sample. A central issue is the difficult link of medical tests with representative populations surveys where confidentiality rules in the case of individual feedback of test results pose a special challenge. In the second part we report how one of the large German panel surveys, the SOcio-Economic Panel (SOEP), is used for a Covid-19 survey which is in line with the WHO guidelines. This survey was started in September 2020 in the framework of a cooperation of the Robert-Koch-Institut (RKI) with the SOEP as the “RKI-SOEP Stichprobe”. First results on the response rate of the survey which is prolongated in October 2021 are reported. It turned out that 5 percent of the previously cooperative interviewees refuse the further participation in the SOEP because of the invitation to the participate in the medical testing. On the basis of all available survey information (IgG antibody test, PCR test and questionnaire) a first estimate reveals that until November 2020 only two percent of the German adults in private households have been infected with SARS-CoV‑2. This number of infections is about twice as high as the officially reported infection cases.