The Dutch Virtual Census of 2001 : A register-based approach combined with survey information

Data from many different sources were combined to produce the Dutch Census tables of 2001. Since the last Census based on a complete enumeration was held in 1971, the willingness of the population to participate has fallen sharply. Statistics Netherlands found an alternative in the Virtual Census, using available registers and surveys. The table results are not only comparable with the earlier Dutch Censuses but also with those of the other countries in the 2000 Census Round.

For the 2001 Census, more detailed information is required than was the case for earlier Census Rounds. The acquired experience in dealing with data of various administrative registers for statistical use enabled Statistics Netherlands to develop a Social Statistical Database (SSD), which contains coherent and detailed demographic and socio-economic statistical information on persons and households. The Population Register forms the backbone of the SSD. Sample surveys are still needed for information that is not available from registers.
To achieve overall numerical consistency across the Census tables set of 2001, the methodologists at Statistics Netherlands developed a new estimation method that ensures numerically consistent table sets if the data are obtained from different data sources. The method is called repeated weighting, and is based on the repeated application of the regression method to eliminate numerical inconsistencies among table estimates from different sources.