Alternatives in Census Designs

1. Alternatives in Census Designs Fourth Taskforce Meeting on Population & Housing Censuses Cairo, 4-5 September 07 Neda Jafar ESCWA jafarn@un.org

2. Background • Most countries conduct traditional census • Headcount at a national level • statistical portrait/profile (composition, distribution & socio-economic correlates) • Governments uses: taxation, military service, planning of schools & hospitals

3. Concerns • Falling response rates • Respondent burden • Cost • Data quality • Desire for more accurate information in non-census years • Lack of timeliness of results • Under coverage

4. Population Census Designs • Traditional census • Traditional census supplemented by annual household surveys • Registered-based census • Administrative sources and sample surveys – virtual census • Sample surveys – rotating census

5. A. Traditional census • Used by vast majority of countries especially outside Western Europe • Complete enumeration of population • Periodically (every 5-10 years)

6. Scope for variation • Enumeration: • by interviewers • self completion form (enumerators/ via postal service) • Location: • Count at location or at usual place of residence • Questions: • Number and type of questions asked may vary extensively • Use of short & long form

7. Australia(population: 19 million) • Every 5 years • A drop-off/pick up methods without any use of the postal service • Level of undercount determined by PES • In 2001 census included questions on use of PCs and internet • 1st time respondents opt giving permission for releasing record in 99 years • In 2006 traditional census

8. AustraliaThe Future • Two major changes planned • Fill in the census form via internet • Use post-back in buildings/apartment blocks (difficult to obtain a response thru pick-up)

9. Canada(population: 30 million) • Usual residents, every 5 years • A drop-off/post-back methods since 1971 • Short form contains 7 questions on basic demographic information • Long form sent 1/5 households on parents’ birthplace, single-sex couples and detailed language question

10. Canada • Gross under coverage rates have been steadily increasing reaching 3.3% in 1996 • In 2006, 2/3 of forms posted out + comprehensive address register • Possible to use the internet to complete the questionnaire

11. B. Traditional census supplemented by annual hh surveys • A traditional census carried out 5/10 yrs • Traditional short form • USA “Re-engineered Pop and Housing Census • Prior census, large-scale annual surveys • Complemented by Community Survey Programme • Surveys since 2003 • Replace long form

12. USAAmerican Community Survey • Collection on monthly samples • Each sample has 3-month collection cycle • Each collection cycle has 3 phases: • Questionnaire mailed • Use of computer-assisted interviews to follow up on non respondents • Personal interview to non-respondent

14. USAThe Future • 2010 census will run on traditional lines • No Long form • Use adm records data for non response hh • ACS with annual sample size of 3m hh • 10years ¼ population cover (>long form) • Low level/annual pop reliable estimates for areas/pop >65,000 available 1st yr of the national survey

15. C. Register-based census • Data from adm. registers combined at micro level • No questionnaires are sent • Covers all private hh and dwellings • In principal, can replace a census completely. • In practice, constrained by the quality & extent of data in registers

17. Italy(population: 57 million) • Every 10 years since to 1861 • Municipal population registers, but each municipality is responsible for its own register and these vary highly in quality • Little incentive to remove people who have died or moved

18. Italy • Significant difference between resident & registered population • Reasons include: • Students registered in one municipality but live n another • People temporary resident in one municipality due to work • People performing military service

19. Italy • Traditionally census was used to update the registers • Registers are used to estimate undercount in census • In 1991 the raw register figures gave 5% undercount (attempts to remove superfluous register data reduced this figure to 1%)

20. ItalyThe Future • ISTAT attempt to standardize population registers and other adm sources to conduct register-based censuses in the future

21. Spain(population: 41 million) • 2001 census was the first in the world to allow all residents to complete their forms via internet • The existence of municipal population registers was central to census operation

22. Spain • Paper questionnaires were pre-printed with information from the registers, to be corrected, if necessary • Identity code and password to enable access to the on-line version • However only 0.1% of households responded

23. D. Adm. sources & Sample surveys • Some countries obtain census information by compiling data from: • different adm registers, and • results of sample surveys

25. The Netherlands(population: 16 million) • 1981 traditional census approach abandoned • Stat Netherlands used adm registers and existing sample surveys • However, data at aggregate level i.e. not possible to integrate them fully with survey data • Legislation allowed administrative records to be used to their full potential for statistical purposes, to reduce costs & respondents burden

26. The Netherlands • Dutch are expected to register with local authorities. • It contains name, address, and basic demographic data (sex, date of birth, and marital status) • Updated once a year on 1 January

27. The NetherlandsSSB • In 1996, a Social Statistics Database (SSB) contains information at an individual level • Covers residents during year based on pooled population register created at the end of the year • Population register is the spine • Other adm records sources: employee insurance schemes, social security, water electricity, pension

28. The NetherlandsSSB • The database enables the statistical office to come up with census related results at any chosen time. • File created in a micro-integration process from diff sources • Transformed and adjusted to conform with concepts and definitions set in the census programme • “Repeated weighting” used to generate numerically consistent table sets for data from different sources

29. The NetherlandsSSB • Matched using variables: sex, date of birth & address • The matching process aims to match over 90% records with no > than 5 % false matches • No Coverage estimate due to lack of another measure of the population • In 2001 called “Virtual Census” based on combined info from diff sources using personal id codes

30. Denmark (population: 5.4 million) • Central population register (CPR) based on municipal registers • Change in address is compulsory, with birth and death registration update CPR • Other adm registers linked to CPR by unique personal identifier • A register-based population census took place in 1976 and following the establishment of a register of buildings and dwellings, a register-based population and housing census in 1981 • Neither of these included any form of fieldwork

31. Denmark • Statistics Act obliges public bodies to make available any information required by Statistics Denmark for statistical purposes • Consult Statistics Denmark when developing registers to ensure that they are appropriately organized for statistical use • Population statistics are produced every year from the CPR and other administrative sources • Population registers associated with the issuing of identity cards are held at municipality level

32. E. Sample Surveys • Large-scale continuous annual surveys or rolling survey • Cover whole country over a period of time rather than on one particular day • Cover a region in its entirety or by taking a sample from every area • Merits • Cost effective • Builds national capacity of NSS • Quality of data on annual basis • Generate new up-to-date stat info for users • Annual estimates from very large sample • Annual time series for various adm domains

34. France • France terms it a “rotating census” • Annual collection of data, during a five-year period • Based on sample surveys providing pop data for the adm districts and annual socio-demographic statistics • Adopted for 4 main reasons: • No pop registers • Several large-scale surveys with results that can be inferred at relatively low domains • While adm data may be available, the files can not be linked coz there are no personal id number system • Until 1999 no legal obligation to carry out a census and no clear legal framework for conducting traditional census

35. Rotating Census – New model • Cover every household over a given period of time (5-10 years) • Proportion of population would not be counted at all in 5 years cycle • Census population <10,000 in communes enumerated once every 5 years • Larger communes a sample survey with 40% population will be enumerated i.e. any given commune will be sampled every year • Sampling frame drawn from building register • Building register was created initially from 1999 census • Updated continually from construction & demolition permits also other sources & surveys

36. Conclusions • Only within Western Europe that a complete enumeration is not always attempted • The Scandinavian countries having good population registers or are about to be, the sole means of enumerating population • The Netherlands has a unique model that makes good use of all the sources available-population registers, other administrative sources and sample surveys

37. Conclusions • France use a rolling model which is part census and part sample survey, and it depends on at least one good administrative sources (building registers) • Italy is looking to develop a more standardized system that can be used to conduct register-based censuses • USA is moving to ‘head count’ plus ‘survey’ model. USA does not have a compulsory population register

38. Conclusions • No two countries are exactly alike even for those that still conduct a traditional census • Not every model would work for every country • Factors depends on • population size, • quality of administrative records, • population base issues, • public perception, • political climate, • funding, • legislative and constitutional issues • existence of a reliable population register

39. Towards a census information-system • The ideal situation is not to one approach • Optimize use of available sources • To avoid faults and to take advantage of the merits of each. • Shift from a census system to a census information-system where the data are: - Rich - Detailed - Dynamic - Continuously updated - Monitors flows ofsequent stock of snapshots