Census and administrative data sources

1. Census and administrative data sources 3: Integration and future development

2. Census and administrative data • Lecture overview Objectives of lecture Introductory questions Census challenges Census data creation from individual records Comparison with administrative sources International comparisons Future directions

3. Objectives • To understand why censuses are becoming less effective • To consider alternative options for large scale social data collection • To explore likely routes from the present situation to the next round of censuses

4. Introductory questions… Do we still need a census? Is a census viable as a means of collecting social data? Can’t we just use administrative records?

5. Census challenges • Declining response rates/difficulty of enumeration • Rising demand for more up to date information • Potential of extracting relevant data from administrative sources

6. Data from census • Reflections on class responses: data collection issues • Coverage • Who was omitted? • Accuracy • Who answered some questions incorrectly? (intentional or unintentional)

7. Extract of person data

8. Imputation • Validation of OCR records • Missing or impossible values • One Number Census methodology • Missing individuals • Missing households

9. Aggregation issues • Table specification prior to data collection • Application of disclosure control methodology • Table level: threshold populations (40 households, 100 persons) • Small cell adjustment (rounding to 0 or 3) • Record swapping

10. Table framework

11. ‘Unsafe’ cells

12. Record swapping

13. Small cell rounding

14. Hard to code variables!

15. NS-SeC • National Statistics – socioeconomic classification • Replaces former social class and SEG • Use for Census and all official surveys • Occupation-based • Based on occupation and employment status

16. NS-SeC: sample subdivisions Source: www.national.statistics.gov

17. NS-SeC

18. Interaction variables

19. The rise of administrative data • Can provide microdata from routinely updated administrative sources • Can take snapshots and produce more frequent estimates than census • BUT no comprehensive administrative population register • Current barriers to data linkage without explicit consent of data subjects

20. International comparisons

21. France: rolling census • Small communes (<10,000) once every five years • Large communes sampled 1/5 per year, to achieve full coverage over five years • No conventional complete enumeration

22. USA: short form and ACS • Abandon long form census (approx 1/6 sample in 2000 census) • Retain short form census for 2010 • American Community Survey, continuously administered, covering 2.5% addresses per year, already started

23. Netherlands: administrative census • Statistical population register • Person ID and address provide links to administrative records • 2001 ‘census’ data constructed by snapshot matching of administrative registers

24. Plans for UK 2011 Census • Methodology essentially as in 2001 • Focus enumeration effort on those areas hardest to count: greater variety of enumeration approaches • Post-out and post-back of census forms • Electronic form tracking system

26. An integrated population statistics system? • ONS consultation document autumn 2003 • 2011 census • Integrated social survey system • Statistical population register • Needs address register • Would require new legislation

27. Lecture summary • International challenges to census • Consideration of census data creation • Retreat from census-taking • Rise of administrative data sources