Statistics Netherlands Division Social and Spatial Statistics Censuses in the Netherlands and the availability of census micro datasets Eric Schulte Nordholt Statistics Netherlands Division Social and Spatial Statistics ESLE@CBS.NL Presentation in Paris

Contents History of the Dutch Census Introduction Virtual Census of 2001 Combining data sources: micro-linkage Combining sources: micro-integration Preliminary work Harmonisation More information about the Dutch Censuses of 1960, 1971 and 2001 Conclusions

History of the Dutch Census TRADITIONAL CENSUS Ministry of Home Affairs: 1829, 1839, 1849, 1859, 1869, 1879 and 1889 Statistics Netherlands: 1899, 1909, 1920, 1930, 1947, 1960 and 1971 Unwillingness (non-response) and reduction expenses  no more Traditional Censuses ALTERNATIVE: VIRTUAL CENSUS 1981 and 1991: Population Register and surveys development 90’s: more registers → 2001: integrated set of registers and surveys, SSD

Introduction Virtual Census of 2001 Why a Census? Statistical information for research and policy purposes What kind of information? Size of (sub)population(s) Demographic and socio-economic characteristics, at national and regional level Gentlemen’s agreement Eurostat: co-ordinator of EU, accession and EFTA countries in the 2001 Census Round Census Table Programme, every 10 years

Combining sources: micro-linkage Linkage key: Registers Social security and Fiscal number (SoFi), unique Surveys Sex, date of birth, address (postal code and house number) Linkage key replaced by RIN-person Linkage strategy Optimizing number of matches Minimizing number of mismatches and missed matches

Combining sources: micro-integration Collecting data from several sources  more comprehensive and coherent information on aspects of person’s life Compare sources - coverage - conflicting information (reliability of sources) Integration rules - checks - adjustments - imputations Optimal use of information  quality improves Example: job period vs. benefit period

Preliminary work Census Programme definitions: not always clear and unambiguous, e.g. economic activity Priority rules (characteristics of) main job (highest wage) employee or employer job or (partially) unemployed job or attending education job or retired engaged in family duties or retired age restrictions One percent samples for all three years Weighting to population totals Protecting according to rules for public use files

Harmonisation (1) For 1960 and 1971 the same variables as for 2001 if not available: constructed based on existing variables in Census data Variables not internationally harmonised (e.g. sex, age, marital status, household position, country of birth, economic status, household size and country of citizenship) same classification and priority rules as for 2001

Harmonisation (2) Household size and country of citizenship: missing for 1960 Religious denomination: only for 1960 and 1971 Place of residence one year prior to the census: only for 2001 International classifications Branch of current economic activity: ISIC / NACE Occupation: ISCO-COM Level of educational attainment: ISCED

Harmonisation (3) 1960 1971 2001 Sex X Age Country of citizenship Marital status Household position Religious denomination Country of birth Household size Place of residence one year prior to the census Economic status Level of educational attainment Occupation Branch of current economic activity

More information about the Dutch Censuses of 1960, 1971 and 2001 1960: http://www.volkstelling.nl/nl/documentatie/1960/ 1971: http://www.volkstelling.nl/nl/documentatie/1971/ 2001 tables: http://www.cbs.nl/en-GB/menu/themas/dossiers/volkstellingen/publicaties/2005-virtual-dutch-census-art.htm 2001 book: http://www.cbs.nl/en-GB/menu/themas/dossiers/volkstellingen/publicaties/2001-b57-e-pub.htm

Conclusions The Dutch Virtual Census of 2001 was successful Pro’s: relatively cheap (cost per inhabitant) quick Con’s: publication of small subpopulations sometimes difficult or even impossible because of limited information Micro datasets for three years (1960, 1971 and 2001) available for research!