household projections for scotland
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Household projections for Scotland. Hugh Mackenzie April 2014. Summary. What are the household projections? How are they produced? Five inputs Seven steps Variant projections How to get Census data & analysis. What are household projections?. - PowerPoint PPT PresentationTRANSCRIPT
Household projections for Scotland
Hugh MackenzieApril 2014
Summary
• What are the household projections?• How are they produced?
– Five inputs– Seven steps
• Variant projections
• How to get Census data & analysis
What are household projections?• Published every two years, 2012-based projections to be
published on 30 July 2014
• Cover a 25 year period
• Projections are produced by:– Council area (also SDP Areas and National Parks later
in the year)– Age of head of household– Household type (based on the number of adults and
children)
• The projections are designated as National Statistics by the UK Statistics Authority.
Input 1: Population Projections• Published every two years by NRS, 2012-based population
projections to be published on 14 May 2014
• Use the 2012 mid-year population estimates as a base
• For following years, this population is aged and estimates are made for:– Numbers surviving to the next year, using mortality rates– The expected number and age/sex structure of migrants– Number of births during the year, using fertility rates applied to the
number of women of childbearing age
• Variant projections are produced using different assumptions about fertility, life expectancy and migration.
Input 2: CE rates Proportion of the population that are resident in
communal establishments• By area, age group and gender• Data on CE residents is collected from a range of sources:
Establishment type Data source Year of dataCare Inspectorate (List of registered establishments) 2012ISD Care Home Census 2012Care Inspectorate (List of registered establishments) 2012SG Looked After Children Statistics 2012NRS Armed Forces Data Collection 2012DASA Regular Forces by Age and Sex 20122011 Census 2011ISD SMR01 (General/Acute) 2012ISD SMR04 (Mental Health) 2010ISD Continuing Care Census (Other NHS) 2012
Hotels, hostels and boarding houses 2011 Census 2011
Prisons SG Prison Statistics 2012SG Education Analytical Services 2012SG Directorate for Learning 2012
Student Halls of Residence - Further Education 2011 Census 2011
NRS Communal establishment address list 2011HESA 2011/12
Other 2011 Census 2011
Children's care
Adult care
Hospitals
Student Halls of Residence - Higher Education
Defence
Residential Schools
Step 1: Calculate private household population
Private household population = Total population x (1 - CE rate)• By area, age group and gender for each year• CE Rates are assumed to be constant
Project headship rates to 2035
Calculate private household
population to 2037 Calculate the
raw household projection
Constrain LA figures to
Scottish totals
Constrain to
household estimates
Minimum adult and child
adjustments
Sum LA figures to give final
Scottish figures
Final projections
Inpu
ts
Population projections
Communal establishment estimates
Headship rates
Household estimates
Household type distribution
Input 3: Headship ratesThe proportion of the private household population that
head a household
• Census data (1991, 2001 and 2011 censuses)• Head of household = first adult recorded on the census
form • By area, age group and household type
• “Non-headship” rates also included (the proportion that do not head any type of household)
• Every person is either the head of a household or a non-head, so for each area/age group the 7 headship rates and the non-headship rate sum to 1.
Comparison of different estimates of the distribution of household sizes in Scotland
0%
5%
10%
15%
20%
25%
30%
35%
40%
1 person 2 people 3+ people
Perc
enta
ge o
f all
hous
ehol
ds
Household size2011 Census2010-based Household projections - principal (2011)2010-based Household projections - alternative headship (2011)
Step 2: Project headship rates• When we only used two censuses, a modified two-point
exponential model was used.
• To make use of three censuses, two sets of projected headship rates are produced using the modified two-point exponential model. i. Using 1991 and 2001 censusesii. Using 2001 and 2011 censuses
• The two sets of projected headship rates need to be combined into a single set of headship rates.
Input 4: Household type distribution in 2012
• Data to come from the Scottish Household Survey (SHS).
• Annual survey, 2012 sample size of just under 11,000 households.
• We make an adjustment to the data based on differences found between the SHS and the Census in 2001 and 2011.
Step 2: Project headship rates (continued)
• Apply weights to the two sets of projected headship rates to combine them into a single set of rates.
• Weights chosen to minimise the difference between the survey data and the household projection.
• Allows up-to-date household type data to be included into the projections.
Step 3: Calculate raw household projectionNumber of heads of household =
Private household population * Headship rate • By area, age group and household type for each year • Number of heads of household = number of households
Project headship rates to 2037
Calculate private household
population to 2037 Calculate the
raw household projection
Constrain LA figures to
Scottish totals
Constrain to
household estimates
Minimum adult and child
adjustments
Sum LA figures to give final
Scottish figures
Final projections
Inpu
ts
Population projections
Communal establishment estimates
Headship rates
Household estimates
Household type distribution
Step 4: Control to Scottish totals• The sum of all LA projections are constrained to the
Scotland projection for each year• By age group and household type
Project headship rates to 2037
Calculate private household
population to 2037 Calculate the
raw household projection
Constrain council figures
to Scottish totals
Constrain to
household estimates
Minimum adult and child
adjustments
Sum LA figures to give final
Scottish figures
Final projections
Inpu
ts
Population projections
Communal establishment estimates
Headship rates
Household estimates
Household type distribution
Input 5: Household estimates
• Produced by NRS annually• Total number of households in each local
authority• Based on council tax data • More up to date household information than the
census data• Two years of data used (2012 and 2013)
Step 5: Constrain to household estimates• The sum of all projected households in each LA is
constrained to the household estimate for 2012 and 2013• 2014 onwards is adjusted by the same proportions as
2013
Project headship rates to 2037
Calculate private household
population to 2037 Calculate the
raw household projection
Constrain council figures
to Scottish totals
Constrain to
household estimates
Minimum adult and child
adjustments
Sum LA figures to give final
Scottish figures
Final projections
Inpu
ts
Population projections
Communal establishment estimates
Headship rates
Household estimates
Household type distribution
Step 6: Minimum adult and child adjustments
• The minimum number of adults required to fill all households in a council is calculated
• This is compared to the number of adults in the private household population in that council.
• In areas where the minimum number exceeds the private household population, the excess number of adults is calculated and the household types adjusted to reduce the number of adults needed. The adjustment is distributed across all multi-adult household types.
• Similar checks and adjustments are made for children if necessary.
Step 7: Calculate Scottish Totals• Final Scotland figures are calculated by adding together
all the local authority figures, so that the minimum adult/child adjustments are taken into account.
Project headship rates to 2037
Calculate private household
population to 2037 Calculate the
raw household projection
Constrain council figures
to Scottish totals
Constrain to
household estimates
Minimum adult and child
adjustments
Sum council figures to give final Scottish
figures
Final projections
Inpu
ts
Population projections
Communal establishment estimates
Headship rates
Household estimates
Household type distribution
Variant projectionsTwo variant projections will be produced in addition to the principal projection:i. Low Migrationii. High Migration
Project headship rates to 2037
Calculate private household
population to 2037 Calculate the
raw household projection
Constrain council figures
to Scottish totals
Constrain to
household estimates
Minimum adult and child
adjustments
Sum council figures to give final Scottish
figures
Final projections
Inpu
ts
Population projections
Communal establishment estimates
Headship rates
Household estimates
Household type distribution
Scotland’s CensusReleases 1 and 2 completedReleases 3A, 3B and 3C now published covering the bulk of Ethnicity, Identity, Language and Religion topics Release 3D to be published 15 May; tables from Population and Households topicsFurther releases dates confirmed shortlyQuick, easy (and FREE!) online access to all the data from www.scotlandscensus.gov.ukAll the standard output tables for all the available census geographiesData visualisations and maps online
Still to come…Remaining Release 3 tables – throughout year Origin-destination statisticsCensus microdata files (Samples of Anonymised Records)Alternative population statistics, eg workplace populationAnalytical reportsFurther details available in Outputs Prospectus on websiteActivity throughout 2014 to explore uses and benefits and what NRS can do to ensure you get the most out of the data
Finally – come to our Census Conference in Edinburgh on 25 June. Details on www.scotlandscensus.gov.uk
Any questions?
For more info, contact:[email protected](0131) 314 4377www.nrscotland.gov.uk
2011 Census website: www.scotlandscensus.gov.ukFollow NRS on Twitter @NatRecordsScot