Utilising population projections for local authority strategic planning (with notes) Stuart Booker
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Transcript of Utilising population projections for local authority strategic planning (with notes) Stuart Booker
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