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2011 Census Data Quality Assurance Strategy: Plans and developments for the 2009 Rehearsal and 2011 Census Paula Guy BSPS 10 th September 2009. Contents. QA Strategy: objectives & prioritisation QA Strategy: components Comparator sources Demographic analysis Census Rehearsal Next steps. - PowerPoint PPT Presentation
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2011 Census Data Quality Assurance Strategy: Plans and developments for the 2009 Rehearsal and 2011 Census
Paula Guy
BSPS 10th September 2009
Contents
• QA Strategy: objectives & prioritisation• QA Strategy: components • Comparator sources• Demographic analysis • Census Rehearsal• Next steps
Context: 2011 Quality Model
Designquality
Operational quality management
Quality assurance
Quality measurement
and reporting
Quality management
High quality
population statistics (as defined
by the CSFs)
Improvements since 2001
• Enhanced address register• Better management information• Wider enumeration base• More questions re: migration and second addresses
Data QA Strategy objectives:
• Ensure 2011 outputs are fit for purpose and meet user expectations
• Understand differences between Census population estimates and rolled-forward MYEs
• Ensure Census population characteristics are accurate• Transparency• Work in partnership with stakeholders• Metadata including quality measures published with data
Planning and prioritisation of data QA to meet these objectives:• Monitor information and data from field operations • Identify and monitor data at key processing stages • Prioritise QA of data items critical for Census
population estimates, including coverage adjustment• Prioritise LADs where data uncertainty is
concentrated, including uncertainty around MYEs, and process them early
• Flexible deployment of QA resource• Automation of QA checks as far as possible
Topic QA
To quality assure detailed level Census data to address errors such as respondent or enumerator error or those introduced by processes such as data capture, edit or imputation. Includes item-level data, low level geographies and multivariate analysis of specified population subgroups.
Demographic QA
To quality assure national, regional and Local Authority District census estimates, drawing on external sources, using demographic indicators and guided by the input and direction of an expert QA panel
Overlaps between Topic & Demographic QA
• Young men• International migrants (short and long term)• Students• Residents and staff in Communal Establishments• Minority ethnic groups• Private renters• People with a second address• Babies under 1• Over 85s• Armed forces
Priority subgroups
Overlaps between Topic & Demographic QA cont …
• Lots of holiday homes• Caravan sites• Second residences• High multi-occupancy• Regeneration areas• Low enumeration or high variability of response• High population change
‘Priority LAs’ identified by areas with:
Demographic and Topic QA
Data load
Apply derivations & filters
Item imputation
Coverage estimation
Coverage imputation
Post-adjustment imputation
Apply complex Derived Vars
Assign output geographies
Disclosure control adjustment
Demographic QA Topic QA
Data flows: Questionnaire tracking, Address Register, Field reports, Administrative and Survey sources
Reconcile multiple responses within a HH
Scanning & recognition
Internet data capture
Implement contingency
LA Estimate
QA PanelReviewsLA, Regional and cumulative totals
Level 2 Topic & Demo QA
checks
QA Panel
Rejects
QA Panel
RejectsQA
Panel Accepts
Local Authority estimates QA process
Level 1 Topic & Demo QA
checks
Proceed to coverage imputation
Comparator data
0 10 20 30 40 50 60 70 80 90
Age coverage (0 to 90+ years)
Super older person databasePension credit claimants
Electoral register2001 CensusPrisoner data
Unemployment benefit claimsHome armed forces data
Foreign armed forces dataHigher education students data
School CensusChild benefit claimants
Pop'n est's by marital statusPatient register
Pop'n est's by ethnic groupRolled forward MYEs
Age coverage of Administrative Sources for 2011 Validation
Black = Within age group, all people are countedGrey = Within age group, looking at characteristicsWhite = Looking at sub-set of population
Additional sources for QA
– International Passenger Survey– ONS survey data sources– University halls of residence capacity data– CLG Gypsy/ traveller numbers– Address Register– Council tax data– CORE HA and LAD properties and tenants data
Demographic analysis at national & sub-national level
• Age/sex specific fertility rates and summary measures
• Age/sex specific mortality rates and summary measures
• Age specific sex ratios• Age/sex in-migration rates• Cohort change over time across censuses
2001 Sex ratio validation: Southampton example
Source: ‘A Quality Assurance and Contingency Strategy for the One Number Census’, ONS
Census Rehearsal
• Basic demographic analyses• Ethnicity and marital status by age & sex• Frequency of households and CEs, including HH by
tenure• CE residents by age• Home Armed Forces by age and sex• Prisoners by age and sex• Students by age and sex• Migration – LT, ST, Internal, International and Cross-
border by age and sex• Caravans/caravan residents• Traveller counts
Next steps
• Rehearsal• Plan for LA engagement• Contingency strategy and admin data linkage• Determine QA checks for 2011• Topic expert input• Assess and secure comparator data sources• Methodological input on tolerances and diagnostic
ranges