Production of high quality statistics depends on the assessment of data quality. Without a systematic assessment of data quality, the statistical office will risk to lose control of the various statistical processes such as data collection,editing or weighting. Doing without data quality assessment would result in assuming that the processes can not be further improved and that problems will always be detected without systematic analysis. At the same time, data quality assessment is a precondition for informing the users about the possible uses of the data, or which results could be published with or without a warning. Indeed, without good approaches for data quality assessment statistical institutes are working in the blind and can make no justified claim of being professional and of delivering quality in the first place. (...)