The micro-geography of UK demographic change Paul Norman Cathie Marsh Centre for Census & Survey Research (CCSR), University of Manchester ESRC RES for 40%

Context Changes in population size & composition: Ageing, births and deaths, migration Some areas, tendency for people to age in situ; others have more transient populations Change in population characteristics: People’s attributes change Attributes of those born & dying differ Migrants may differ in their socio-demographic characteristics from the populations they leave and join

Aims Quantify and map changes in population size and social characteristics which occurred in small geographical areas between the 1991 and 2001 Censuses Calculate components of demographic change to understand the relative contributions of natural change and migration Calculate deprivation indexes to identify areas becoming differently deprived over time Inform on locations where the population is ageing or more transient, along with small area trends in unemployment, health and deprivation

Specification Time points: 1991 and 2001 mid-years Coverage: England, Wales, Scotland & Northern Ireland Geography: CAS wards (E, W & NI) & CAS sectors (Scotland), 2001 Census (2003) definitions Data inputs 1991 & 2001 Census populations 1991 & 2001 National Statistics Office mid-year estimates (MYEs) 1991 to 2001 Vital Statistics (VS4) 1991 & 2001 Census deprivation indicator variables

Example outputs … by further geographic detail by more LA types & GB+NI coverage E&W population change Net migration = population change ± natural change

Related research questions Which of the demographic components of change accounts most for changes in population? Which areas are gaining or losing population through migration? Stratify the above by area type? Local authority type Deprivation quintile Urban-ness / rurality

Example outputs Townsend deprivation scores 1991 and 2001 (E&W) Also for Carstairs scores & for GB+NI coverage

Example outputs Non-home ownership 1991 & 2001 (E&W) Unemployment 1991 & 2001 (E&W)

Related research questions Are areas becoming more or less deprived over time or is it, once deprived, always deprived? If areas are less deprived, is this the result of regeneration policy, gentrification or inner city revitalisation? Role of local knowledge? How have patterns of unemployment changed? Has public housing gone into private ownership? What are the relationships between health & deprivation?

Technical stuff 1991 and 2001 ‘ward’ populations not comparable: Differences in 1991 & 2001 Census population definition (students) Boundary changes Need to: Adjust populations to mid-year & to a consistent geography Allow for changed view of level of 1991 Census undercount

Estimating 1991 ‘ward’ populations consistent with 2001 ward estimates Revisit ‘Estimating with Confidence’ estimates EwC estimated 1991 small area mid-year populations as: Census 'usual residents' ± student term-time adjustment + change between census night and mid modification adjustment (table consistency) + armed forces adjustment + residual non-response (by age) Area-specific application of official district level adjustments

Estimating 1991 ward mid-year populations Following 2001 Census, ONS revised 1991 district MYEs For sub-district wards: Need to distribute revisions on area-specific basis Scale EwC adjustments by difference between 1991 MYEs pre- & post-revisions Adjust EwC populations & adjustments to allow for 1991 to 2001 boundary changes Ensure small area data sum to the 1991 revised district MYEs

Estimating net migration With all data adjusted to be consistent with the 2001 boundary definitions Population change 1991 to 2001 = 2001 ward ONS MYEs – 1991 ward EwC(v.2) MYEs Births – Deaths (natural change) Net migration = population change ± natural change

Currently Working on method to revise EwC estimates Validating lookup tables between 1991 and 2001 ward definitions Negotiating with National Statistics Offices to rebase 1990s VS to 2001 boundary definitions ONS (supplied) GROS (supplied) NISRA (in progress)