Utilising population projections forlocal authority strategic planning

(with notes)

Stuart Booker

Financial Planning and Research TeamFife Council

BSPS Annual ConferenceUniversity of Southampton18-20 September 2006

• Context

• National data sources

Quantitative analysis of GAD/GROS projections for Fife

Conclusions

• Fife Council data sources

Comments on Fife Council and other data

• Future work

How to synthesise information for strategic planning?

Overview

Context• Fife is Scotland’s third most populous local authority

• Fife covers a geographical area of 512 sq. m.

• Fife has significant rural and urban populations

Glasgow City 578,790Edinburgh, City of 457,830Fife 356,740

…Eilean Siar 26,370Shetland Islands 22,000Orkney Islands 19,590SCOTLAND 5,094,800

Context• The Edinburgh economy has a significant impact on Fife

• Fife’s share of the Scottish population is increasing

• Fife public services operate to a common boundary, including: Council, Health Board, Police Force, Waste Plan Area ...

• Fife has well developed community planning

Fife ScotlandFife

Share (%)

1995 349,720 5,103,690 6.852005 356,740 5,094,800 7.00

FPR Requirements

Aim: to understand Fife’s future population to allow strategicplanning of Fife Council (and Partnership) services

Income Expenditure

Aggregate External Finance Service demand Fife share of key client groups Size of key client groups

Number of householdsCouncil Tax Number of households Unit cost Household composition Other client group trends

Other household trendsThree year settlement Population projections

Fife Council RequirementsPresent use of population data

Fife Council

EducationService

PlanningService

OtherServices

StructurePlan

Serviceplanning

GROS projections

ScotXEDpupil data

School rollprojections

• GAD (ONS) UK projections made every two years

• GROS produce variant projections for Scotland

• GROS produce projections for local authority areas (32) and health boards (15)

Advantage

• Provides self-consistent figures at local authority level across Scotland

necessary for projecting resource distribution in future years

Disadvantage

• No projections available below local authority level

necessary for planning future service delivery at a local level

Issues

• Migration assumptions and migration data volatility

National Data SourcesGeneral Register Office for Scotland (GROS) projections

National Data SourcesGeneral Register Office for Scotland (GROS) projections

Projected Fife total population

300,000

325,000

350,000

375,000

400,000

20

04

20

06

20

08

20

10

20

12

20

14

20

16

20

18

2002 based projection 2004 based projection

Question: are the GROS projections sufficiently reliable for strategic planning of Council services?

National Data SourcesGeneral Register Office for Scotland (GROS) projections

Method: quantitative analysis of GROS projection methodology

• Spreadsheet cohort-component model of Fife population

• Using GAD/GROS implementation

• Using GAD published fertility/mortality rates

• Using local scaling factors for Fife published by GROS

• Using age-sex migration data for Fife supplied by GROS

• Validated against principal and variant projections for Scotland

Note: not reconciled back to Scottish national total

Variant projections for FifeFertility: method

Scotland fertility rates by year

and age

Cohort componentmodel

Projectionby year and age

Local scaling factorfor Fife

Principal orvariant fertility

rates

The same method has been used to produce variant projections for highand low life expectancy.

Variant projections for FifeFertility: results for high fertility projection

High fertility projection: TFR of 1.8

Principal projection: TFR of 1.6

Fife local fertility factor: 1.019

Principal projection High fertility Difference by 2024

Age 2004 2024 2004 2024 Difference Difference

Band population population population population (number) (%)

0-4 18,715 20,622 18,715 23,046 2,424 11.8

5-11 29,420 29,084 29,420 32,684 3,600 12.4

12-17 27,804 24,195 27,804 26,753 2,558 10.6

18-34 72,921 75,367 72,921 75,511 144 0.2

35-49 79,798 70,559 79,798 70,559 0 0.0

50-64 67,292 78,968 67,292 78,968 0 0.0

65-69 17,146 23,069 17,146 23,069 0 0.0

70-74 14,577 20,102 14,577 20,102 0 0.0

75-79 11,765 19,044 11,765 19,044 0 0.0

80-84 8,814 12,649 8,814 12,649 0 0.0

85-89 3,977 7,956 3,977 7,956 0 0.0

90+ 2,371 5,119 2,371 5,119 0 0.0

Total 354,600 386,734 354,600 395,460 8,726 2.3

Variant projections for FifeFertility: results for high fertility projection

Note: continuing decline in population of secondary school age

-20.0

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0-4 5-11 12-17 18-29 30-44 45-59 60-74 75-89 90+ Total

Ch

an

ge

(%

) 2

00

4 t

o 2

02

4

Principal projection High fertility

Variant projections for FifeMortality: results for high life expectancy projection

Principal projection High life expectancy Difference by 2024

Age 2004 2024 2004 2024 Difference Difference

Band population population population population (number) (%)

0-4 18,715 20,622 18,715 20,641 19 0.1

5-11 29,420 29,084 29,420 29,096 12 0.0

12-17 27,804 24,195 27,804 24,195 0 0.0

18-34 72,921 75,367 72,921 75,407 40 0.1

35-49 79,798 70,559 79,798 70,639 80 0.1

50-64 67,292 78,968 67,292 79,287 319 0.4

65-69 17,146 23,069 17,146 23,271 202 0.9

70-74 14,577 20,102 14,577 20,338 236 1.2

75-79 11,765 19,044 11,765 19,397 353 1.9

80-84 8,814 12,649 8,814 13,022 373 2.9

85-89 3,977 7,956 3,977 8,344 388 4.9

90+ 2,371 5,119 2,371 5,646 527 10.3

Total 354,600 386,734 354,600 389,283 2,549 0.7

High life expectancy: 81.4 (males) and 85.1 (females) at birth in 2031

Principal life expectancy: 79.1 (males) and 83.6 (females) at birth in 2031

Fife local mortality factor: 0.928 (males) and 0.939 (females)

Variant projections for FifeMortality: results for high life expectancy projection

-40.0

-20.0

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

0-4 5-11 12-17 18-29 30-44 45-59 60-74 75-89 90+ Total

Ch

ang

e (%

) 20

04 t

o 2

024

Principal projection High life expectancy

Note: significant increase in oldest age groups

Variant projections for FifeMigration: method

• The age-sex structure for migration varies significantly across Scotland

• Use long term migration assumption from 2002 based projection

• Reflects age-sex structure of local authority for (relatively) recent conditions

Note: can also look at natural change

Variant projections for FifeMigration: difference in assumption between 2002 and 2004

Assumed long-term net migration Fife council area: Females

-150

-100

-50

0

50

100

150

200

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90+

Age

Ass

um

ed n

et m

igra

tio

n

Females 2004-based Females 2002-based

Principal projection 2002 based migration Difference by 2024

Age 2004 2024 2004 2024 Difference Difference

Band population population population population (number) (%)

0-4 18,715 20,622 18,715 16,573 -4,049 -19.6

5-11 29,420 29,084 29,420 24,722 -4,362 -15.0

12-17 27,804 24,195 27,804 22,151 -2,044 -8.4

18-34 72,921 75,367 72,921 68,346 -7,021 -9.3

35-49 79,798 70,559 79,798 64,196 -6,363 -9.0

50-64 67,292 78,968 67,292 77,792 -1,176 -1.5

65-69 17,146 23,069 17,146 23,026 -43 -0.2

70-74 14,577 20,102 14,577 20,133 31 0.2

75-79 11,765 19,044 11,765 19,064 20 0.1

80-84 8,814 12,649 8,814 12,592 -57 -0.5

85-89 3,977 7,956 3,977 7,895 -61 -0.8

90+ 2,371 5,119 2,371 5,028 -91 -1.8

Total 354,600 386,734 354,600 361,518 -25,216 -6.5

Variant projections for FifeMigration: results for 2002 based migration

Question: if a 5% difference between projections is significant,when does the earliest significant difference occur?

Variant projections for FifeMigration: earliest significant difference between projections

Earliest year at which error exceeds threshold(total population)

2005

2010

2015

2020

2025

0 10 20 30 40 50 60 70 80 90 &over

Age

Yea

r

Note: this type of approach allows a useful timescaleto be put on the set of projections in question

National Data SourcesSummary (recording all differences from principal projection > 5%)

Age band High lifeexpectancy

Low lifeexpectancy

Low fertilityHigh

fertilityAlternativemigration

0-4 (-12.2%)

(11.8%)

(-19.6%)

5-11 (-10.9%)

(12.4%)

(-15.0%)

12-17 (-7.5%)

(10.6%)

(-8.4%)

18-34 (-9.3%)

35-49 (-9.0%)

50-64

65-69

70-74

75-79

80-84

85-89

90+

(-9.8%)

(10.3%)

Totalpopulation

(-6.5%)

Fife Council SourcesSchool roll projections

• Fife Council Education Service produces school roll projections

• Based on recent trends and placing requests

• Uncertain how well trends capture recent increase in housing stock

• Two projections produced at present

• A ‘trend-based’ projection

• A ‘strategic’ projection, including an additional allowance for new housing

• There is a notable agreement between the school roll projections

and two variant projections for Fife (principal and alternative migration)

• Agreement for primary pupils is slightly better than that for

secondary pupils

Fife Council SourcesComparison of school roll projections with Fife variant projections

20,000

22,000

24,000

26,000

28,000

30,000

20

04

20

05

20

06

20

07

20

08

20

09

20

10

20

11

20

12

20

13

20

14

20

15

20

16

20

17

20

18

20

19

20

20

20

21

20

22

20

23

20

24

Year

Pu

pil

nu

mb

ers

School roll 'strategic' projection GROS principal projection

Trend-based school roll projection 'Alternative' migration projection

Fife Council SourcesUse of council sources to produce projections at

• School roll projections are produced at school catchment and

area (former district council) level

• School roll projections provide a way to relate future changes in

the pre-school and school age population to projections at the

Council area level

• Information of the local housing requirement

Future WorkHow to synthesise information for strategic planning?

Coherent view of population change in Fife and Scotland as a whole

Measures to assess utility of GROS

projections

Fife Partnership projections

e.g. Popgroup

Fife Council data

GROS projections

NHS data