subnational population projections for england

Subnational population projections for the West Midlands

Anthony Szary, Office for National Statistics

A presentation given at State of the Region: Implications of Population Change event, 31 March

2009.

This presentation forms part of the Observatory’s ongoing State of the Region dialogue between policy makers and researchers on the theme of

population change.

Subnational Population Projections

for West Midlands

Anthony Szary

Centre for Local & Regional StatisticsOffice for National Statistics

Context

• Subnational Population Projections for England produced every 2 years.

• Latest are 2006 based, projecting population, births, deaths, net migration forward for 25 years to 2031

• Used by:– Department of Health, CLG, DCSF– Local Authorities, Health Authorities– Regional/sub-regional bodies, academia etc

• Based on past trends and not policy based

• Use latest mid year population estimate as base

• Calculated at building brick (LA district) level

• Constrained to national projections

General Principles

Pp = Pc + B – D + Mw+ MI

• single year of age, gender and area

• repeated each projection year

Cohort Component Method: Basic Formula

• Ageing on

• Fertility

• Mortality

• Internal migration

• International migration

Stages in the model

• Births registrations form basis

• Local differentials calculated from observed data (past 5 years)

• Provides projected births by age of mother

• Controlled nationally – scaling local estimates

Fertility

• Uses death registrations

• Local differentials calculated from observed data (5 years)

• Projected numbers of deaths by age/sex

• Controlled nationally

Mortality

• Internal migration assumptions are derived using data from the Patient Register Data System (PRDS); GP registrations &NHSCR

• Produce matrices of movements by origin/destination by single year of age and sex

Internal Migration - 1

• Model out migration probability, fitting curves to historic data (5 years)

• Probability applied to population to give out migrants for that area

• Apply matrix to calculate in-migrants for each destination area

Internal Migration - 2

Typical Migration Age Profile

Age profile

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

Age

0

Age

3

Age

6

Age

9

Age

12

Age

15

Age

18

Age

21

Age

24

Age

27

Age

30

Age

33

Age

36

Age

39

Age

42

Age

45

Age

48

Age

51

Age

54

Age

57

Age

60

Age

63

Age

66

Age

69

Age

72

Age

75

Age

78

Age

81

Age

84

Age

Prop

rtio

n of

mig

rant

s

• Migration streams dictated by data:– rest of world measured by International Passenger

Survey (IPS)– rest of UK (cross border), based on PRDS– rest of world that are seeking asylum or visitor

switchers (Home Office/IPS)

• Distribute national in and out migrants as per Mid Year Estimates method (propensity to migrate models utilising LFS data)

International Migration

• Each element is controlled to national totals

• Projected population is new base

• Repeat process for 25 years

Population Controls

• Aggregate building bricks to other geographies, such as:

– strategic health authorities– Government Office Regions

Aggregation

• Draft projections produced

• Consultation on first year migration assumptions

• Any adjustments applied

• Publication of final projections and supporting material

Processes

• Difficulties in measuring migration

• ONS has switched primary focus of IPS from the measurement of tourism to the measurement of migration

• Models to allocate international migrants more accurately being developed

Issues

• Projections are inherently uncertain

• A variant is simply a different set of assumptions applied to the same base data

• ONS sub national population projection variants will (resources permitting) be produced for the following different assumptions– High and low fertility– High and low mortality– High and low migration– Zero net-migration

Variants

Variants for England projections

Sub National Population Projections (English regions) - Total Population (000s)

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032

Tota

l Pop

ulat

ion

(000

s)

West Midlands North East North WestYorkshire & Humber East Midlands EastLondon South East South West

• Population of West Midlands projected to rise more slowly than most other regions

Population projection for West Midlands

NE

E

SE

Lon

NW

EMWM

Y&HSW

Source: ONS Sub National Population Projections 2006

21.0% 20.2% 19.7%18.5%

15.6% 15.6% 14.9%

11.4%10.2%

6.9%

0%

5%

10%

15%

20%

25%

EastMidlands

East South West Yorkshire &Humber

South East England London WestMidlands

North West North East

Popu

latio

n G

row

th (%

)Projected population growth between 2007 & 2027 English regions


• Over next 10-20 years significant further ageing:

• Proportions in 10-30 age band to decline significantly

• Proportions in 65+ age band to rise significantly

Projected changes in Age Structure

2

3

4

5

6

7

8

0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85+

Age Band

Prop

ortio

n of

Tot

al P

opul

atio

n %

2007

2017

2027

Population Profile Projections – 2007 to 2027 West Midlands


• Proportion of WM population in 65+ age band to rise in line with, but remaining somewhat above, projections for England

• London continuing to have a much lower proportion in this age band, and the SW a significantly higher proportion

Ageing in comparison to other regions

10

15

20

25

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032

Prop

ortio

n of

Tot

al P

opul

atio

n %

West Midlands England North East North West Yorkshire & Humber

East Midlands East London South East South West

Proportion of population aged over 65 – English regions


• Projections indicate ageing will be much more pronounced in certain Local Authorities

• eg. by 2027 proportions in 65+ age band projected to almost double in Redditch & Tamworth, but to rise only marginally in Birmingham & Coventry

Ageing by Local Authority

5

10

15

20

25

30

35

40

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shire

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Prop

ortio

n of

Tot

al P

opul

atio

n %

2007 2017 2027

Population & projections 2007 to 2027 Aged over 65 – West Midlands Local Authorities


Contact details

Anthony SzaryCentre for Local and Regional StatisticsOffice for National StatisticsE [email protected] +44 (0)121 202 3256Web www.ons.gov.uk

Stephen HowarthDeputy Chief ExecutiveWest Midlands Regional ObservatoryE [email protected] +44 (0)121 202 3258Web www.wmro.orgBlog http://wmro.wordpress.com

Rosie DayResearch AnalystWest Midlands Regional ObservatoryE [email protected] +44 (0)121 202 3286Web www.wmro.orgBlog http://wmro.wordpress.com

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