1. The micro-geography of UK demographic change 1991-2001 Paul Norman School of Geography, University of Leeds Understanding Population Trends & Processes ESRC RES-163-25-0012 for 2005-07 @ 40%

2. Aims 1. Quantify and map changes in population size and social characteristics which occurred in UK’s small geographical areas between the 1991 and 2001 Censuses 2. Calculate components of demographic change to understand the relative contributions of natural change and migration 3. Calculate deprivation indexes to identify areas becoming differently deprived over time 4. Inform on locations where the population is ageing or more transient, along with small area trends in unemployment, health and deprivation Small area geography of reporting: wards & equivalents

3. Calculating population change 1991 and 2001 ‘ward’ populations not comparable: Boundary changes Differences in 1991 & 2001 Census population definition (students) To estimate a 1991 base population, need to: Adjust populations to mid-year & to a consistent geography Allow for changed view of level of 1991 Census undercount Collaboration with Ludi Simpson and Albert Sabater at CCSR Examples here using Birmingham

4. 1991 to 2001 boundary change Adjust 1991 data to the 2001 boundaries

5. 1991 to 2001 boundary change Apportion data using weighted postcode distribution District boundary 1991 District boundary 2001 Apportion 1991 ward data Uffdown ward 1991 Waseley ward 1991 Method: Simpson (2002) & Norman et al. (2003) Longridge ward

6. Estimating official 1991 populations 1990s viewpoint (original) Official Mid-Year Estimates (MYEs) for 1991 districts Based on 1991 Census ‘usual residents’ with adjustments for: Student term-time adjustment Demographic change between Census day & mid-1991 Armed forces postings adjustment Census under-enumeration (c. 1.2 million people) ‘Non-response’ adjustments (by age) ‘Other’ adjustments

7. Official MYEs for 1991 districts Populations Adjustments

8. Estimating with Confidence (EwC) 1991 small area MYEs 1990s viewpoint (original) EwC estimated 1991 small area mid-year populations as: Census ‘usual residents’ with allowances for: Student term-time adjustment Demographic change between census and mid-1991 Modification adjustment (table consistency) Armed forces adjustment Residual non-response (by age) An area-specific application of official district level adjustments

9. EwC 1991 adjustments (original) Non-response adjustments Other adjustments

10. EwC 1991 adjustments (original)

11. After 2001 Census 1991 MYEs revised Adjustments Non-response revised downwards Other adjustments remain the same Populations

12. Revising 1991 EwC small area MYEs Post-2001 viewpoint (revised) For sub-district areas, by age & sex: Adjust EwC populations & adjustments to allow for 1991 to 2001 boundary changes Distribute original EwC non-response adjustments revisions on area-specific basis scaled by difference between 1991 MYEs district pre- & post-revisions No revisions made to the ‘other’ (student, armed forces, timing or modification) adjustments, which are still assumed to apply Ensure small area data sum to the 1991 revised district MYEs

13. Revising the non-response adjustment For males aged 20-24 in Birmingham

14. Assessing EwC revised Total male non-response Difference in estimates related to size of original non- response Total male population Different downward revisions

15. Assessing EwC revised Relationships should be maintained

16. Implications of EwC revisions 1991 to 2001 population change Original cf. Revised … Net population change: Growing wards grow more Contracting wards contract less

17. Implications of EwC revisions

18. Different age-sex structure of ward populations District adjustments Non-response revised downwards Other adjustments remain the same Ward adjustments Reduction in number of males by age In proportion to size of original non-response

19. Implications of EwC revisions EwC Original & Revised used as a denominator: Male unemployment Male (<65) SMRs

20. Extras about this work Geographical data conversions are 1991 EDs to 2001 OAs Improved geographical detail & aggregation versatility Revisions to EwC by quinary age-group OA 1991 populations to be estimated by single year of age to 90+ IPF using extra information on 0s, late teens and 80-89 & 90+ Albert Sabater will extend these estimates by ethnic group Rest of UPTAP project to follow