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Plausibility Ranges for Population Estimates
Focusing on ranges for children
Outline
Aims
Data sources
Approaches
Results for children
Research on other age groups
Summary of benefits
Aim
Explore and
Combine
High estimate of population
Low estimate of population
Administrative sources
Data sources: Patient Register (0-15)
GP Patient Register
Usually resident population aged 0 to 15
Usual residents registered with a GP
Short term migrants
List inflation or registration lag for out-migrants
Multiple or duplicate NHS numbers
School boarders
Non-registration or registration lag for in-migrants
Erroneous list cleaning
• Adjusted to remove short-term migrants and duplicate records
Data sources: Child benefit (0-15)
Child Benefit
Usually resident
population aged 0 to 15
Usual residents registered for Child Benefit
Change of details lag for out-migrants
Children living abroad
Short term immigrants
Non-registration or registration lag
Change of details lag for in-migrants
School boarders
Clerical claims
• Adjustments to the child benefit data to compensate for coverage differences were not possible.
Data sources: Live births (age 0)
Live Births
Usually resident
population aged 0
Usual residents born in LA j
Immigration between birth and mid-year
In-migrants between birth and mid-year
Emigration between birth and mid-year
Out-migrants between birth and mid-year
Infant mortality
• The live births data has been adjusted for infant mortality (IMR).
• To allow for internal migration between birth and mid-year, the live births minus IMR has been re-distributed to local authorities using Child Benefit data.
Data sources: School Census (3-15)
School Census
Usually resident
population aged 3 to 15
Usual residents at a state maintained school
Short term immigrants
Change of details lag for out-migrants
Multiple pupil reference numbers
School boarders
Children aged 3and 4
Attendance lag for immigrants
Children at independent schools, pupil referral units or home educated
Change of details lag for in-migrants
• Although the School Census was available at individual record level, it was not possible to make any adjustments for over coverage.
Aggregate data: tolerance range approach
Mid-point (LA j)
Low source (LA j)
High source (LA j)
Step 1
Difference(LA j)
Patient Register = 3000
Mid-Point = 2800
Child Benefit = 2600
For example...
Difference= 400
Aggregate data: tolerance range approach
Range size (LA j) = 2 x Difference (LA j)
Difference (400)from Step 1
Range size(LA j = 800)
Step 2
Mid-point (LA j)
Low source
High source
2800
Upper limit (LA j) 3200
Lower limit (LA j) 2400
Aggregate data: tolerance range approach
10% of LAs10% of LAs
Step 3Percentage range size (LA j)
= Range size (LA j) / Mid-point(LA j)
min %
max %
• Range size (%) restricted to prevent very narrow or wide ranges.
rank of LAs
Record level data: linkage approach
Record-level sources (LA j)e.g. School Census e.g. Patient Register
Linked datasetunlinked School
Censusunlinked Patient
Register
Lower limit Upper limit
High linkage rate =Narrow range
for LA j
Summary of approaches
Age group Approach
Under 1s Combines Patient Register and Live Births adjusted with Child Benefit
1 to 4 year olds Combines Patient Register and Child Benefit
5 to 7 year olds8 to 11 year olds12 to 15 year olds
Lower limitLinked Patient register and school Census (England)
Upper limitCombines Patient register and Child Benefit
Source
Tolerance range
Tolerance range
Lower limit – linkage approach
Upper limit – Tolerance range
Results: data sources summary
Results: LA example - Adur (males)
0200400600800
10001200140016001800
estimated population of
under 1s
estimated population, age 1 to 4
estimated population age 5 to 7
estimated population age 8 to 11
estimated population
age 12 to 15
Adur, Males
Results: LA example - Adur (females)
0200400600800
10001200140016001800
estimated population of
under 1s
estimated population, age 1 to 4
estimated population age 5 to 7
estimated population age 8 to 11
estimated population
age 12 to 15
Adur, Females
Results: summary e.g. all LAs (males 8-11)
•Relatively few areas with estimates out of range
•Where areas have estimates out of range, often by small amount
•Rare for areas to have estimates more than 5% above upper limit or below lower limit
•Ranges quite narrow for ages 0 and 1-4, and more areas slightly out of range
Plausibility ranges for children
• Plausibility ranges are proof of concept at this
stage
• Project allowed us to demonstrate techniques
using aggregate and record level data
• Results published 27 March 2012 (report and
Excel-based tool)
• Results were discussed with LAs at roadshows
• Plan to further evaluate ranges in future
Research: 18-24 age group
• Age at which people most likely to migrate
• Sources: L2, HESA, Patient Register
• Where Patient Register is lower than population
estimates, these areas are predominantly
university towns
• Tested approach with HESA and PRDS linkage
• Further work on matching required
Research: 25-59/64 age group
• Investigated use of confidence intervals around
estimates Local Labour Market Database (L2)
• For quinary age groups sample size often small
• Difficulty with excluding short-term migrants from
latest tax-year data
• Not yet able to apply a universal method for all LAs
using the L2
Research: over retirement age group
• Patient Register and Work and Pensions
Longitudinal Study compared
• Data sources were often very close to each
other, potentially leading to ranges that were not
diagnostically useful
• Large differences between the sources for
females aged 60-64 and males aged 65-69
• Surprising result that population estimate higher
than PR and WPLS in 90+ age group
Summary of benefits
• Gathered together metadata and research on administrative sources in one report
• Knowledge of administrative sources fed back to teams quality assuring 2011 Census
• Helped inform future population estimates methods (e.g. school boarders)
• Evidence that small number of LAs may have had undercount of 0 & 1 year olds at 2001 Census
• Ranges may be used in quality assuring estimates in future