Maintaining the quality of the registers used in the Danish Census

Abstract

Statistics Denmark has a long tradition in producing yearly censuses based on administrative registers. The census is established through a match of different statistical registers, covering the necessary information for the Census. Maintainance of the quality of the registers, is carried out in different subject matter departments, and the paper presents some examples of both continous quality control and more ad hoc based exercises. Continuous quality control, for example, is done by a proces of linking and checking information from the Central Population Register with birth and death certificates – to ensure a total coverage of statistics on births and deaths. An example of ad hoc based quality control is also presented in the form of a comparison of data at the indvidual level from different sources – the register-based Labour Force Statistics and the sample-based Labour Force Survey. The magnitude of discrepansies on specific variables, e.g. data on sector of employment, can be evaluated in this way. Finally the concept of Integrated Data Collection is introduced, illustrating the advantages of the data supplier (the administrative authority) and the data user (Statistics Denmark) cooperating in the collection of data. The paper concludes that the more intense the use of a register is, the more errors can be found and corrected.