The Dutch Censuses of 1960, 1971 and 2001 Producing public use files in the IPUMS project Wijnand Advokaat Statistics Netherlands Division Social and Spatial Statistics Presentation in July 2005

2 Contents Introduction Statistics Netherlands 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 Conclusions

3 Introduction Statistics Netherlands (1) The Central Statistical Office (CBS) (no regional offices) Statistics Netherlands wants to compile and publish undisputed, coherent up-to-date statistical information that is relevant for practice, policy and research More about Statistics Netherlands: exists since 1899 since 3 January 2004 semi-independent organisation (still government funding) more than 2000 employees two buildings (Voorburg in the West and Heerlen in the South)

4 Introduction Statistics Netherlands (2) Central Commission for Statistics (CCS) Independent body to assess and decide on our work programme No direct influence by the government Members of the CCS: Employer organisations Trade Unions Universities and other research institutes Members of parliament Ministries

5 Introduction Statistics Netherlands (3) Statistics Netherlands’ organisation: Executive board and central departments (300 employees) - Division of Business Statistics (740 employees) - Division of Social and Spatial Statistics (450 employees) - Division of Macro-economic Statistics and Dissemination (440 employees) - Division of Technology and Methodology (380 employees) More information about Statistics Netherlands: Our English website: StatLine: link on the homepage

6 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

7 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

8 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

9 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

10 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

11 Harmonisation For 1960 and 1971 the same variables as for 2001 if not available: constructed based on existing variables in Census data International classifications ISIC / NACE ISCO-COM ISCED Variables not internationally harmonised same classification and priority rules as for 2001

12 More information about the Dutch Censuses 1960: : tables: /census-2001.htm /census-2001.htm 2001 book: htm

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