Household Projections for Northern Ireland 9 th September 2009
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Transcript of Household Projections for Northern Ireland 9 th September 2009
Household Projections for Northern Ireland
9th September 2009
Dr David Marshall & Dr Jos IJpelaar
Demography & Methodology BranchNorthern Ireland Statistics & Research Agency
Introduction
• 2006-based Household projections
• Health Card Registration Data– Persons/household information– Use for household propensities– Use for household transition indicators
• Implementation in 2008-based projections
2006-Based
Household Projections
• Housing Growth Planning
• Household composition trend 1991-2001 Census
• First published in January 2005
• Updated using 2006-based population projections; in March 2008
NI Household Projections
Population Projections
1991 Census
Household Projections
Mid-Year Population Estimates
Fertility, mortality
and migration assumptions
Registered Births
Registered Deaths
Estimated Migration
2001 Census
Schematic Projection Process
Householdformation
assumptionsOther Sources
Household Membership Probabilities
• 18 Household categories– seven sizes (1 - 7+ persons) and three types (adults
only, 1 adult with children, 2+ adults with children)
• 14 Age groups
• Projected probabilities for membership of each household category for each age-sex group
• Constant age-sex probability of being resident in communal
0.0
0.2
0.4
0.6
0.8
1.0
1991 2001 2011 2021 2031
Methodology: 2-Point Exponential
10
1991
1991
20011991 1
111
i
i p
ppp
10
1991
1991
20011991
i
i p
ppp
For p2001 >= p1991
For p2001 < p1991
Some special cases
• Constant probabilities for under 19s– Evidence that the 1991-2001 trend of smaller families
and more single parent households does not continue in the period 2001-06
• Complete “households with children” with adults, remaining adults distributed over childless household types
• Complete couple households with females aged 75+ from single households
Population Projection by age and sex (2011)
15,000 10,000 5,000 0 5,000 10,000 15,000
0
10
20
30
40
50
60
70
80
Age
(yea
rs)
Persons
Male
Female
Population Projection by age and sex (2011)
15,000 10,000 5,000 0 5,000 10,000 15,000
0
10
20
30
40
50
60
70
80
Age
(yea
rs)
Persons
Male HH
Male Com
Female HH
Female Com
Subtractprojected communal population
Population Projection by age and sex (2011)
15,000 10,000 5,000 0 5,000 10,000 15,000
0
10
20
30
40
50
60
70
80
Age
(yea
rs)
Persons
Other HH
1+child
2+child
Communal
Children in householdswith children
Population Projection by age and sex (2011)
15,000 10,000 5,000 0 5,000 10,000 15,000
0
10
20
30
40
50
60
70
80
Age
(yea
rs)
Persons
Other HH
1+child
2+child
Communal
Completehouseholds-with-childrenwith adults
Population Projection by age and sex (2011)
15,000 10,000 5,000 0 5,000 10,000 15,000
0
10
20
30
40
50
60
70
80
Age
(yea
rs)
Persons
1 person2 adult3+ adult1+child2+childCommunal
Allocateremainingadults overchildlesshouseholds
Population Projection by age and sex (2011)
15,000 10,000 5,000 0 5,000 10,000 15,000
0
10
20
30
40
50
60
70
80
Age
(yea
rs)
Persons
1 person2 adult3+ adult1+child2+childCommunal
Completingelderly couplehouseholds
Health Card
Registration Data
NI Health Card Data
• 1.817M health records (2008)
• 1.775M population estimate (2008)
• Primary source for official migration estimates
• Date of Birth, Sex & Address
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,0000
-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
+
Census (M) Health Card (M) Census (F) Health Card (F)
Health Card (2001) vs. Census Household population by age and sex
NI Health Card Data
• Using address database to allocate unique address identifier
• Household definition: all persons at same address
• Communal establishments: exclude all addresses with 15+ persons
NI Health Card Data - Issues
• Accuracy depends on notification
• Incomplete address information
• Persons not families
• Armed Forces
• List Inflation
PersonID Age Sex HseholdID Year
P0001 24 F HH1 2001
P0001 25 F HH1 2002
P0002 26 M HH1 2001
P0002 27 M HH1 2002
P0003 0 F HH1 2002
P0003 51 M HH2 2001
P0003 52 M HH3 2002
P0004 79 F HH4 2001
P0004 80 F HH4 2002
Health Card Registration Data - Example
0%
20%
40%
60%
80%
100%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
+
Census - single adult with chldren
Census - 2+ adults with children
2001 Census Households with children, Females
0%
20%
40%
60%
80%
100%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
+
Health Cards - single adult Health Cards - 2+ adults
Census - single adult Census - 2+ adults
Health Card (2001) vs. Census Households with children, Females
0%
10%
20%
30%
40%
50%1
5-1
9
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
+
2001 20042006 2008
Health Card Data, 2001-2008Females in 2 adult households (without children)
Household Transition
• Age-sex probability of persons in household type A in year t being in household type A,B,C… in year t+1
• Does not take account of other persons in household
• Cannot be done using Census data
Household Transitions Example:Household type in 2008 for females
who were aged 25-29 in childless 2-adult households in 2007
2 adults
1 adult
3+ adults
2+ adults & child
1 adult & child
Left NI
Household Type 2008
1 adult 2 adults 3+ adults1 adult &
child2+ adult
& child
Household Type 2007
1 adult 60% 15% 5 % 12 % 8 %
2 adults 8 % 63 % 10 % 2 % 16 %
3+ adults
5 % 7 % 80 % 9 % 7 %
1 adult & child
2 % 1 % 0 % 79 % 19 %
2+ adult & child
2 % 2 % 4 % 6 % 85 %
Household Transitions Example (2)Females aged 25-29yrs, 2007-8 (excl. migration)
0%
10%
20%
30%
40%
50%200
8
200
9
201
0
201
1
201
2
201
3
201
4
201
5
201
6
201
7
201
8
201
9
202
0
202
1
202
2
202
3
202
4
202
5
202
6
202
7
202
8
202
9
203
0
203
1
1 adult 2 adults 3+ adults
1 adult & child 2+ adult & child
Household Transitions Example (3)Females 25-29yrs, projections with transition matrix
Left NI
2007
Stayed
2007
Stayed
2008
Arrived in NI
2008
1 adult 12% 11% 10% 14%
2 adults 14% 12% 12% 17%
3+ adults 39% 33% 29% 35%
1 adult & child
9% 12% 13% 5%
2+ adult & child
26% 32% 35% 28%
Total 100% 100% 100% 100%
Household Type - MigrationFemales aged 25-29yrs, 2007 and 2008
Using Health Card
Registration Data in
2008-based Household Projections
Census trend vs. Health Card dataMales aged 4-15yrs, 1 adult & 1 child household
0%
1%
2%
3%
4%
5%
6%
7%
8%
199
1
199
3
199
5
199
7
199
9
200
1
200
3
200
5
200
7
200
9
201
1
201
3
201
5
201
7
201
9
202
1
Census 2pt.Exp.Census trend
Census trend vs. Health Card dataMales aged 4-15yrs, 1 adult & 1 child household
0%
1%
2%
3%
4%
5%
6%
7%
8%
199
1
199
3
199
5
199
7
199
9
200
1
200
3
200
5
200
7
200
9
201
1
201
3
201
5
201
7
201
9
202
1
Census 2pt.Exp.Census trend Health Cards
Census trend vs. Health Card dataMales aged 4-15yrs, 1 adult & 1 child household
0%
1%
2%
3%
4%
5%
6%
7%
8%
199
1
199
3
199
5
199
7
199
9
200
1
200
3
200
5
200
7
200
9
201
1
201
3
201
5
201
7
201
9
202
1
Census 2pt.Exp.Census trendHealth Cards Health Cards (calibr)Health Card - linear trend
Further Developments
• 2008-based household projections will be published in Spring 2010– Health Card data for projecting propensities
• Review methodology– Introduce cohort analysis with transition matrices– Constrain transitions with projected births, deaths
and migration– Alternative household types?
• Explore use of alternative data sources– Longitudinal Study?
Household Projections for Northern Ireland
9th September 2009
http://www.nisra.gov.uk/demography/default.asp21.htm
Dr David Marshall & Dr Jos IJpelaar
Demography & Methodology BranchNorthern Ireland Statistics & Research Agency