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Population and Migration Seeking your views Welcome and introductions Centre for Demography

Population and Migration Seeking your views Welcome and introductions Centre for Demography

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Page 1: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Population and Migration

Seeking your views

Welcome and introductions

Centre for Demography

Page 2: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Population and Migration

Welcome and Introduction

ONS Centre for Demography

Centre for Demography

Page 3: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Aims of the day

• Communicate the latest work being carried out to improve population statistics through– the 2011 Census and – the Improving Migration and Population Statistics

programme

• Census– progress on planning and executing the 2011 Census– methodology for assessing coverage– quality assurance of the census population estimates

• Improving Migration and Population Statistics– present the indicative impacts– explain user engagement process– provide chance to feedback on results

Page 4: Population and Migration Seeking your views Welcome and introductions Centre for Demography

AGENDA am

• 9.30 - 10.00 Registration and coffee• 10.00 Welcome and introduction to the day • 10.15 Census overview

– This session will provide an overview of the census components that are key to producing Census population estimates

– To provide an update on progress on recent events, such as the census rehearsal.

• 10.45 Census coverage– This will cover the methodology being developed to assess census coverage– It will focus on improvements that address many of the lessons from 2001

• 11.15 – 11.30 Coffee break• 11.30 Census data quality assurance

– To provide an update on Census data quality assurance plans– To summarise the processes and evidence to be used to validate Census local

authority estimates• 12.00 Questions• 12.30 – 1.15 Lunch

Page 5: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Agenda pm

• 12.30 – 1.15 Lunch• 1.15 Improving Migration and Population Statistics

Session I– Introduction and Background– User engagement– Indicative Impacts

• 2.30 – 2.45 Tea Break• 2.45 Improving Migration and Population Statistics

Session II– Open discussion

• 4:00 Close

Page 6: Population and Migration Seeking your views Welcome and introductions Centre for Demography

High level timetable

• 18 January 2010– Final date for comments

• 27 May 2010– Revised 2002-08 population estimate for LAs– 2008-based Subnational Population Projections

• 27 March 2011 – Census day

Page 7: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Domestics

• Fire Exits• Fire Alarm• Refreshments

Tea and Coffee about 11:15

Lunch at about 12:30

Tea and Coffee about 2:30

Close at about 4:00

• Toilets• Delegate Packs• Questions

Page 8: Population and Migration Seeking your views Welcome and introductions Centre for Demography

2011 Census Overview

Garnett ComptonONS Demography Seminar - December 2009

Page 9: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Introduction

• Reminder – key design changes• Where are we now?

• Census rehearsal• Census address register• Census legislation• Census stakeholder engagement• Census outputs

• Key milestones

Page 10: Population and Migration Seeking your views Welcome and introductions Centre for Demography

What’s new since 2001?

• Questions• New Qs on population characteristics• New Qs on population base

• Address register• Field operation

• Distribution via post• Distribution of field staff• Questionnaire tracking

• Internet data capture

Page 11: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Census rehearsal areas

Rehearsal areas:• Lancaster – 62,000 • Newham – London – 40,000 • Isle of Anglesey – Wales 34,000

Small scale test:• Birmingham – 17,000

Objective:

• To validate 2011 Census field procedures and supporting systems

Page 12: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Rehearsal systems/procedures

• Recruitment of field staff• E-learning• Flexible deployment of field

staff• Questionnaire Tracking• Publicity• Local Authority &

Community engagement• Census coverage survey

Page 13: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Rehearsal systems/procedures

• Address register • Printing• Royal Mail delivery & collection• Internet completion• Public contact centre• Online help systems• Census Management

Information System

‘best internet survey I’ve ever seen’ – Prof Phil Rees

Page 14: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Rehearsal publicity

Page 15: Population and Migration Seeking your views Welcome and introductions Centre for Demography
Page 16: Population and Migration Seeking your views Welcome and introductions Centre for Demography
Page 17: Population and Migration Seeking your views Welcome and introductions Centre for Demography
Page 18: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Engaging Advertising

• Reaching students and young people where they spent their time with some engaging advertising

Page 19: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Total Returns by Completion Method

(up to 29 November)(provisional)

0

10000

20000

30000

40000

50000

60000

Num

ber

of Q

uest

ionn

aire

s

All

Postal

IDC

Page 20: Population and Migration Seeking your views Welcome and introductions Centre for Demography

REHEARSAL RESPONSE

• 35% overall (so far – 29/11)

• Action taken to improve response• More staff in Newham• More community liaison• More advertising• Targeted letters/questionnaires

• Possible reasons – logistical• postal delays (stuck in system?)?• time of year?• contact patterns?

• Possible reasons – behaviour• lack of trust?• not important – voluntary?• lack of awareness?

21/10 29/11

Anglesey 34% 42%

Lancaster 30% 39%

Newham 10% 21%

Overall 25% 35%

Birmingham 11% 21%

Page 21: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Rehearsal – some early thoughts (1)

What worked well:

• Recruitment, pay and training• Daily receipting• Questionnaire tracking system

• Linking replacements/deactivating addresses• Generating follow-up lists

• Internet data collection/Web self help• Actions to improve response rates

Page 22: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Rehearsal – some early thoughts (2)

What needs reviewing and refining:

• Understanding low response rates• Targeting of initial field resource• Mixture of full and part-time hours• Training and doorstep messages• Management information

• Specification of reports

• Improve awareness and routing to IDC• Working with LAs to increase publicity

Page 23: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Where are we now

Page 24: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Address register

• Data sent to suppliers for resolution(Royal Mail, Intelligent Addressing)

• Unmatched addresses sent to LAs• Address check implementation started

• In the field May – Aug 2010• 15% of postcodes targeted on mismatches and multi-

occupation

• Strong focus now on communal establishments• Prioritised for target populations – 3rd party suppliers• Special address check staff covering all of E&W

Page 25: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Number of mismatched addresses sent to LAs for resolution

0

50

100

150

200

250

0-499 500-999 1000-1499

1500-1999

2000-2499

2500-2999

3000-3499

3500-3999

4000 ormore

Number of mismatched addresses

Nu

mb

er

of

LA

s

Page 26: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Census legislation

• White Paper - 11 December 2008

• Census Order – tabled 21 October 2009

• Debated by the Delegated Legislation Committee - 30 November

• Full Lords debate – 2 December

• Privy Council - likely 10 Feb

• Census Regulations – March 2010

• EU legislation

Page 27: Population and Migration Seeking your views Welcome and introductions Centre for Demography

LA engagement - foundations

• Stakeholder website launched September• New LA engagement advisory groups initiated

• Operational advisory group• Communication advisory group

• Local authority partnership guide launched October• Local authority communication toolkit• Regional networks established by many census

regional champions• Online communities of practice

Page 28: Population and Migration Seeking your views Welcome and introductions Centre for Demography

What’s next for LAs?

• Second round of regional meetings hosted by CRCs• Regional meetings for LA communication teams to

launch toolkit and councillor handbook• Defining the ways of working during the operational

phase• Local partnership plans to agree commitments by each party

around– Media relations and publicity– Community liaison– Support with logistics– Ongoing contact mechanisms

Page 29: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Community liaison

• Liaison with national organisations representing target population groups continues

• Some good offers of help and support• Communication materials for community groups to use

being developed for March 2010• 40 Community advisors start September 2010 to liaise

with black and ethnic minority target population groups• Partnership plan with LA will also cover community

liaison activities

Page 30: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Census outputs - vision

• Web as the primary dissemination route• Flexibility for end users to create own products• Bulk download of data via the web

• Web functionality provided jointly with external partners

• 2001 comparisons which exploit stable geography (OAs)

• Microdata products provided via secure mechanisms

• UK Wide Approach with common disclosure control

Page 31: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Outputs – next steps• Continue technical development

• Demonstrate Prototype & agree partnership proposals Spring 2010• Populate 2011 System with some 2001 data December 2010

• User Consultation Round• Main content consultation in Dec 2009 • Geography consultation in Dec 2009• Publish Proposed 2011 Outputs Product set end- 2010

• Disclosure Control• UKSDC approach agreed September 2009• Complete alignment of Disclosure Control/Technical constraints and

User requirements Summer 2010

• Finalise proposals for• Microdata delivery• Analytical Uses

Page 32: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Census – milestones

2010 2011

Sep-09 - Dec-09Census Rehearsal

Oct 09 - Jan 10Census Order ?

May - SeptemberAddr. Checking Field Activity

Mar 11 - Jun 11Census Field Operation

27 March, 2011Census Day

MarchField staff recruitment starts

AugustArea Managers start work

2012Processing continues until April 2012

MayCensus Coverage Survey starts

NovSystem Readiness testing starts

JunFirst delivery of data

Jan - FebCensus Regulations?

Page 33: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Finally ……

• Coverage adjustment

• Quality assurance

• Quality census relies on other key aspects:• Address register• Census Operations:

– Questionnaire tracking– Publicity– Recruitment– Field operations and procedures

Page 34: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Thank you

Questions?

Page 35: Population and Migration Seeking your views Welcome and introductions Centre for Demography
Page 36: Population and Migration Seeking your views Welcome and introductions Centre for Demography

AGENDA – Census Coverage

1. Background2. Coverage in the 2001 Census3. 2011 Methodology overview4. Key changes5. Summary

Page 37: Population and Migration Seeking your views Welcome and introductions Centre for Demography

WHAT IS THE PROBLEM?

• Despite best efforts, census won’t count every household or person

• It will also count some people twice

• Users need robust census estimates - counts not enough

• In 2001:– One Number Census (ONC) methodology was developed to

measure undercount– estimated 1.5 million households missed– 3 million persons missed (most from the missing

households but some from counted households)– Subsequent studies estimated a further 0.3 million missed

• In 2011 we want to build on the ONC, as broadly it was successful

Page 38: Population and Migration Seeking your views Welcome and introductions Centre for Demography

2001 CENSUS UNDERCOUNT BY AGE-SEX

Underenumeration of Census by agegroup

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

16.0%

0 1-4 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+

Agegroup

ON

C/C

en

sus

Males Females

Page 39: Population and Migration Seeking your views Welcome and introductions Centre for Demography

RESPONSE RATES BY LOCAL AUTHORITY

Page 40: Population and Migration Seeking your views Welcome and introductions Centre for Demography

COVERAGE ASSESSMENT PROCESS OVERVIEW

Estimation

Matching

Adjustment

2011 Census

Quality Assurance

Census Coverage

Survey

Page 41: Population and Migration Seeking your views Welcome and introductions Centre for Demography

AREAS OF IMPROVEMENT• Elements of CCS Design• Estimation methodology• Measuring overcount• Adjustments for bias in DSE• Imputation

• Motivated by:– lessons learnt from 2001– 2011 Census design e.g. use of internet

Page 42: Population and Migration Seeking your views Welcome and introductions Centre for Demography

THE CCS DESIGN

• Similar to 2001 CCS:– 300,000 Households– Sample of small areas (postcodes)– 6 weeks after Census Day– Fieldwork almost identical

• Improvements:– Designed at LA level, not for LA groups– Refined Hard to Count index (5 levels) using up to date data

sources– Use Output Areas as PSUs– Select 3 postcodes per OA– Revised allocation of sample (using 2001 patterns)

Page 43: Population and Migration Seeking your views Welcome and introductions Centre for Demography

THE CCS DESIGN (2)

• What does this mean?– Each LA will have its own sample – at least 1 OA for each

hard to count level– Sample is more skewed to LAs with ‘hardest to count’

populations (with an upper limit of 60 OAs)• More LAs will have estimates based on their own data

• Especially in London and for big cities

– HtC index will be ‘up to date’– Most LAs will have 3 HtC levels

• Most London areas only had one in 2001

• Will be a 40%, 40%, 10%, 8%, 2% distribution

Page 44: Population and Migration Seeking your views Welcome and introductions Centre for Demography

MATCHING AND ESTIMATION

• Estimation based on Dual System Estimation• Used mainly for wildlife applications• Requires two ‘counts’ of the population• Requires the two counts to be matched

• Use standard survey estimation techniques to generalise the DSEs to the whole population• Ratio estimator

• Trout, Catfish & Roach provides a fishing example of the principles of the method – Available in delegate packs

Page 45: Population and Migration Seeking your views Welcome and introductions Centre for Demography

ESTIMATION

• Obtained lots of data from 2001 to be able to explore whether improvements can be made

• One issue was at what level to estimate undercount to best fulfil the assumptions of the methodology (Postcode, Groups of Postcodes)

• One key issue was whether we should group LAs by geography or by ‘type’

• Improvements:• Confirmed that using DSE at OA level is sensible• Confirmed that we should group LAs by geography• Use simple Ratio estimator• Confirmed that 2001 LA estimation method is still

best

Page 46: Population and Migration Seeking your views Welcome and introductions Centre for Demography

ESTIMATION (2)

• What does this mean?– The estimation methodology is much the same as it

was– Should be slightly easier to explain– We will group LAs that don’t have enough sample

with their neighbours until that group has enough sample

– More LAs will have enough sample to produce direct estimates

Page 47: Population and Migration Seeking your views Welcome and introductions Centre for Demography

OVERCOUNT

• In 2001, estimated around 0.4% overcount (duplication)– No adjustments made– Not integrated into methodology

• For 2011, expecting overcount to be higher– More complex population– Use of internet in 2011 Census

• Strategy is to:– A) Build a process to identify and remove obvious cases

(multiple response resolution)

– B) measure and make net adjustments on the remainder

– i.e. for the latter we are NOT removing duplicates

Page 48: Population and Migration Seeking your views Welcome and introductions Centre for Demography

OVERCOUNT (2)

• Methodology:– Select targeted samples of census records

• Second residences• Students• Children

– Very large sample (~600,000k records)

– Automatic matching algorithm to identify duplicates

– Clerical checking of matches• expect to see ~13,000 duplicates• Also use the LS to QA the estimates

– Estimation of duplication rates by GOR and characteristics• estimating which is the correct record

– Why not do whole database and remove them?• High risk of making false positives and thus removing too many!

Page 49: Population and Migration Seeking your views Welcome and introductions Centre for Demography

OVERCOUNT (3)

• What does this mean?– Population estimates will be reduced where there is overcount

– We will be able to say how much adjustment was made due to overcount

– The duplicates will still be in the data, we just won’t impute as much for undercount

Page 50: Population and Migration Seeking your views Welcome and introductions Centre for Demography

DSE BIAS ADJUSTMENTS

• Assumptions underpinning DSE:– Homogeneity

– Independence

– Accurate Matching

– Closure

• DSEs usually have some bias, mostly due to failure of homogeneity assumption

• In 2001 Census we made a ‘dependence’ adjustment

• This showed that we need to have a strategy for measuring this

Page 51: Population and Migration Seeking your views Welcome and introductions Centre for Demography

DSE BIAS ADJUSTMENTS (2)• Mitigate as much as possible:

i. Post-stratify DSE so heterogeneity is minimised

ii.Independence in CCS field processesiii.Design Matching to get accuracyiv.Collect CCS on same basis as Census

• Measure remaining bias– Specific adjustments – e.g. Movers, Overcount– Residual biases global adjustment

• Improved adjustment using Census address register

• Looking at improving age-sex distribution

Page 52: Population and Migration Seeking your views Welcome and introductions Centre for Demography

DSE BIAS ADJUSTMENTS (3)• What does this mean?

– We will be making adjustments to the estimates based on plausible external data e.g.• Household counts• Sex ratios

– This will be part of the methodology– Also can be used if QA determines estimates are implausible

– Haven’t ruled out triple system estimation

Page 53: Population and Migration Seeking your views Welcome and introductions Centre for Demography

COVERAGE ADJUSTMENT

• Imputation methodology had problems converging– Sometimes resulted in poor quality results

• Improvements:– Model characteristics at higher geographies– Allows more details to be modelled– Some additional topics in the CCS included in

models:• Migration variable (internal, international)• Country of birth (UK and non-UK)

– Non-controlled variables imputed by CANCEIS

• What does this mean?– Better Imputation quality– Characteristics of imputed improved

Page 54: Population and Migration Seeking your views Welcome and introductions Centre for Demography

SUMMARY

• Coverage assessment is an integral part of the 2011 Census

• It will again define the key census outputs (estimates at LA level by age and sex) and adjust the database

• We learnt a lot of lessons in 2001 and have been working to address them

Page 56: Population and Migration Seeking your views Welcome and introductions Centre for Demography

ESTIMATION results

Table 1: Overall relative bias (%) for simple ratio estimation method with DSEs at various levels

Estimation Area DSE Level LB LJ NX KK WB KO NA SH Total Perfect CCS 0.61 0.28 0.14 0.34 0.30 0.07 0.20 0.12 0.27 Postcode -1.99 -0.56 -0.84 0.05 0.07 -0.14 0.00 -0.07 -0.46 Cluster -0.58 -0.08 -0.29 0.25 0.23 -0.01 0.08 0.05 -0.05 Hard to Count -0.28 -0.08 -0.16 0.24 0.24 -0.03 0.10 0.08 0.01 2001 robust DSE -1.59 -0.42 -0.62 -0.05 0.05 -0.20 0.43 0.13 -0.31 Census -28.19 -13.33 -12.23 -8.01 -7.38 -6.08 -4.85 -4.09 -10.92 2001 Undercount -24.80 -12.90 -8.50 -6.50 -4.40 -5.90 -3.40 -2.40 Table 2: Overall RRMSE (%) for simple ratio estimation method with DSEs

at various levels

Estimation Area DSE Level LB LJ NX KK WB KO NA SH Total Perfect CCS 2.31 1.43 1.37 1.19 1.14 0.89 0.84 0.82 0.50 Postcode 2.93 1.48 1.56 1.12 1.08 0.88 0.78 0.80 0.56 Cluster 2.35 1.44 1.41 1.20 1.14 0.90 0.80 0.82 0.50 Hard to Count 2.35 1.43 1.40 1.20 1.13 0.89 0.81 0.83 0.50 2001 robust DSE 2.58 1.35 1.43 1.06 1.03 0.83 0.94 0.80 0.51

Page 57: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Other results

Table 3 – Overall results comparison for the South East Region

EA Type Relative bias RRMSE95% Confidence Interval width Census Coverage

Contig 0.16% 0.33% 48418 93.4%

Noncontig 0.07% 0.31% 46128 93.4%

Table 7 – Overall results comparison for the North East Region

EA Type Relative bias RRMSE95% Confidence Interval width Census Coverage

Contig -0.01% 0.46% 22177 94.4%

Noncontig 0.06% 0.48% 23314 94.4%

Alternative non-

contiguous 0.01% 0.46% 22110 94.4%

Page 58: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Lessons learnt - One Number Census

• Not designed to be the lifeboat for a poor census

• Not robust enough to cope with extreme Census failures (Westminster)

• Not robust enough to cope with extreme changes in areas on the ground (Manchester)

• Correlation bias is a problem

• Overcount measurement was not adequate

Page 59: Population and Migration Seeking your views Welcome and introductions Centre for Demography

2011 Aims and Objectives

• Measure undercount• Measure overcount• Address lessons from 2001• Take into account changes

- In census design- In those at risk of undercount

• Accuracy to be as good or better than in 2001- 0.2 per cent confidence interval nationally- 2 per cent on half million population total

Page 60: Population and Migration Seeking your views Welcome and introductions Centre for Demography
Page 61: Population and Migration Seeking your views Welcome and introductions Centre for Demography

2011 Census data QA: An update on planning and proposals for the validation of LA estimates

Louisa BlackwellPaula GuyGlen Doubleday

2011 Census & ONSCD Seminar on Population and MigrationDecember 2009

Page 62: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Contents

• Census data QA objectives

• Overview of the data QA: topic and demographic QA

• The QA Panel and its role

• The process for assessing and approving Census LA estimates; evidence and data

• Options for adjusting Census population estimates

• The LA consultation pilot

• Supporting analysis from 2009 to 2011

Page 63: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Census data QA objectives

• Ensure 2011 Census outputs are fit for purpose and meet user expectations

• Understand differences between Census population estimates and rolled-forward mid year estimates

• Ensure Census population characteristics are accurate

• Transparency

• Work in partnership with stakeholders

• Metadata including quality measures published with data

Page 64: Population and Migration Seeking your views Welcome and introductions Centre for Demography

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.

Page 65: Population and Migration Seeking your views Welcome and introductions Centre for Demography

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

Page 66: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Demographic and Topic QA

Data load

Apply derivations & filters

Item imputation

Coverage estimation

Coverage imputation

Post-adjustment imputation

Apply complex DVs

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

Page 67: Population and Migration Seeking your views Welcome and introductions Centre for Demography

The QA Panel and its roleRole: To assess Census population estimates at LA / regional /

national levels and recommend acceptance / rejection or further research

Membership– Head of the ONS Census Design Authority (Chair)– Head of Census Quality Team– Methodology Division experts in coverage adjustment– ONS Centre for Demography experts in mid-year population

estimation and projection– Independent expert demographers– Other relevant parties, such as representatives of the LGA,

NISRA, GROS, WAG and non-UK member(s)

Page 68: Population and Migration Seeking your views Welcome and introductions Centre for Demography

The QA Panel indicative timetable

Key dates Meetings / Activities

July 2010 - July 2011 Quarterly to agree terms of reference, methods and data

July 2011 - Feb 2012 Weekly to agree LA estimates

Feb - March 2012 Overcount, visitor, second residence reconciliation agreed

March - May 2012 Final LA, regional and national estimates approved

Page 69: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Local Authority checking process - overviewLevel 1• Basic set of checks that all LAs go through

Level 2• Additional suite of checks tailored to address particular data problems

in LAs that didn’t pass level 1

Level 3• Final checks, following any adjustments/ contingency action and

following post-coverage adjustment item imputation

National / local reconciliation• Cumulative checks above LA level and other geographies

Page 70: Population and Migration Seeking your views Welcome and introductions Centre for Demography

LA estimate

Level 1 checks

QA PanelreviewsLA estimates along with national and local reconciliation

LOCAL AUTHORITY ESTIMATES QA PROCESS

Page 71: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Level 1 checks (against comparators)Demographic indicators:• Age / sex distributions, sex ratios, young and old dependency ratios,

fertility and mortality measures

Key estimates and distributions:• Households (vs. Address Register and Council Tax), household size,

ethnicity, students, internal and international migrants, armed forces

Local evidence:• Supplied by LAs and available via other sources

Qualitative/ quantitative evidence:• Census data processing diagnostics, Management Information and

LA profile information

Page 72: Population and Migration Seeking your views Welcome and introductions Centre for Demography

LA sex ratios compared to England

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

Age

Se

x r

ati

o

MYE PR LB Ch B Sch C Pens MYE England

Page 73: Population and Migration Seeking your views Welcome and introductions Centre for Demography

National / local reconciliation

Demographic indicators:• Internal, home country and international migration flows and patterns• Sex ratios, mortality and fertility rates

Data checks:• Cumulative counts• Multiple enumeration rates and reconciliations (eg visitors / usual

residents)• Population sub-group cumulative totals

Pause and review to check progress:• After approximately 20 per cent of LAs have been processed

Page 74: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Implement adjustment options

LA estimate

Level 1 checks

QA PanelreviewsLA estimates along with national and local reconciliation

Level 2 checks

QA Panel

Rejects

QA Panel

Accepts

Proceed to imputation

LOCAL AUTHORITY ESTIMATES QA PROCESS

QA Panel Provisional Acceptance

Page 75: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Level 2 checks

Address Register / Questionnaire Tracking analysis:• Reconciliation against dummy forms and source updates, CE counts

and second address counts

Demographic indicators:• Household size by ethnic group

Administrative source comparisons for key population sub-groups:• Students, armed forces personnel, gypsies and travellers, school

children pensioners, migrants, etc.

Page 76: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Options for adjusting Census population estimates• Alternative post-stratification of the Dual System Estimation

• Alternative post-stratification of areas• Borrow strength between areas• Use visitor / multiple enumeration / student reconciliations to revise

populations in the coverage assessment process• Calibration to:

– national sex ratio etc– alternative administrative source – estimate from analysis of Longitudinal Study members

• Triple System Estimation

Page 77: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Implement adjustment options

LA estimate

Level 1 checks

QA PanelreviewsLA estimates along with national and local reconciliation

Level 2 checks

QA Panel

Rejects

QA Panel

Rejects

QA Panel

Accepts

Proceed to imputation

LOCAL AUTHORITY ESTIMATES QA PROCESS

Level 3 checks

QA Panel recommendation to

ONS senior managers

QA Panel Provisional Acceptance

QA Panel

Rejects

Page 78: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Level 3 checks

• Applied on the fully adjusted Census database

• Provide a check on the plausibility of estimates for key population sub-groups

• Include validation of key variables / distributions

• Final check on demographic indicators

Page 79: Population and Migration Seeking your views Welcome and introductions Centre for Demography

LA engagement objectives for Census QA• To improve LAs’ understanding and confidence in the Census

resultso Presentation of Census QA information at stakeholder eventso Feedback received at working / advisory groupso Publication of key materials

• To develop the best possible understanding of each LA’s population ahead of the Census

o Census Liaison Manager user guideo QA studieso LA pilot

Page 80: Population and Migration Seeking your views Welcome and introductions Centre for Demography

LA engagement key tasksTask Date

ONS contacts pilot LAs and requests data Dec 09

Pilot LAs send intelligence to ONS End Jan 10

ONS assesses evidence and evaluates pilot Mid March 10

ONS begins QA studies Early April 10

LAs in QA studies return intelligence for assessment End June 10

Remaining LAs provide intelligence to ONS End Sept 10

ONS assesses remaining LAs intelligence End March 11

Page 81: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Indicative timetable for 2009 - 2011 analysis plan

Analysis plan in preparation for LA validation / contingency

Analyses Pilot LAs QA studies Remaining LAs

Level 1 checks Oct 09 - Mar 10 Mar 10 - July 10 July 10 - Dec 10

New administrative microdata*

Oct 09 - Mar 10 Mar 10 - July 10 TBA

Data matching pilots

Feb 10 - May 10

TBA TBA

*School Census, HESA, Migrant Worker Scan, Patient Registers, DWP LS Master Index, Welsh School Census, Project Semaphore, Claimant Count Cohort, GENSERV

Page 82: Population and Migration Seeking your views Welcome and introductions Centre for Demography

CLOSE

Page 83: Population and Migration Seeking your views Welcome and introductions Centre for Demography

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

Population estimates byPatient register

Population estimates by ethnicRolled forward MYEs

Age coverage of Administrative Sources for 2011 Validation

Page 84: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Improving Migration Statistics

ONS Centre for Demography

Centre for Demography

Page 85: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Indicative impacts

• Impacts are indicative– so will change before final publication in May 2010

• Revisions are distributional– No significant effect at England and Wales level– Improving internal and international migration

distributions

• Aim is successive improvements to estimates at LA level– So better comparison to 2011 Census

Page 86: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Distribution of impact across all local areas 2002 to 2008

Camden has been excluded from this chart

02

04

06

08

0N

umb

er o

f Loc

al A

utho

ritie

s

-6 -4 -2 0 2 4Percentage Impact

Page 87: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Cumulative percentage revision to mid-2008 population as a result of improvements to migration estimates

Page 88: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Background

• Importance of migration: – Key component of population change– Changing society– Economic situation

• Drivers for improvement work: – relevant statistics– multiple purposes and customers– timeliness, quality

• Census provides benchmark– Migration estimates used to measure population

between censuses

Page 89: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Migration: Front page news

Page 90: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Context - Change

UK Components of Change 1998 to 2008

0

50

100

150

200

250

300

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Thousands

Net migration & other changes

Natural change

UK Components of Change 1998 to 2008

0

50

100

150

200

250

300

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Thousands

Net migration & other changes

Natural change

Page 91: Population and Migration Seeking your views Welcome and introductions Centre for Demography

International moves.Over seven years mid-2002 to mid-2008

Internal moves across an LA boundary.Over seven years mid-2002 to mid-2008.

Page 92: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Vision

Migration and Population Statistics meeting user needs:- At the right time- Covering the relevant populations- Measuring change accurately (national and local)- Detecting turning points

And are trusted as authoritative:- Based on range of developed best up to date sources- Enhanced, transparent, sustainable, statistical methods- With quality measures

By highly engaged users

Page 93: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Improvements already delivered

• Improvements to methods in 2007 – distribution of migration, emigration modelling

• Improved port survey– Better coverage of migrants at key ports in IPS

• Improved migration reporting– Quarterly report and less confusion on multiple outputs

across government

• Indicators of migration and improved timeliness• National Estimates of short-term migration

Page 94: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Early indicator of migration

Page 95: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Issues Addressed By Improvements

1. Internal migration (within England & Wales)• Internal migration estimates dependent on all

individuals re-registering quickly with a GP when they move

• Some students are slow to re-register when they move to university and/or when they move at the end of their studies

2. International immigration • 2001 Census data currently used to distribute

immigration between local areas• Doesn’t reflect changes between 2001 and 2008

Page 96: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Improvements that change previously published numbers

• Student adjustments using HESA data– HESA data of student residential (term-time) addresses– Compare against GP lists by single year of age and sex– Adjust where current data underestimates student flows

• Distribution of international immigration using administrative and other sources– Using a model to replace Census data

• Refined model for emigration data– Listened to comments on earlier model– Learned lessons from immigration modelling– New model better reflects nature of data– Immigration main driver for emigration distribution

Page 97: Population and Migration Seeking your views Welcome and introductions Centre for Demography

The Future

• More extensive use of administrative data for statistical purposes– More data sharing gateways– Linking and matching between sources

• Use of new data sources– e-Borders roll-out

• Better quality measures– Ability to make statements about confidence in figures

• 2011 Census– Basis of estimation for the next decade

Page 98: Population and Migration Seeking your views Welcome and introductions Centre for Demography

User Engagement

Centre for Demography

Page 99: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Overview

• Aims of user engagement• Timetable• Supporting material• How to respond• What we’ve learned from QA groups• Refinements

Page 100: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Aims of user engagement

• Provide all users with the opportunity to comment and ask questions

• Seek user responses to specific questions

• Document clearly the changes being made and the indicative impacts

• Concurrent user engagement - Consultation on subnational population projections for England

Page 101: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Timetable

• User Engagement- 30 November to 18 January

• BSPS Discussion Session on Improvements- 7 January (Leeds) & 11 January (London)

• Final Impacts Summary- March/April

• Publication of Subnational Population Projections & Revised Mid-year Estimates (mid-2002 to mid-2008)

- 27 May

• Publication of Mid-2009 Population Estimates- 24 June

Page 102: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Key documents published on November 30

www.statistics.gov.uk/imps

• Introduction paper• Overarching paper• Feedback form on the improvements• Impact paper• Impact tables & charts• Frequently asked questions

Page 103: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Supporting Documentation Published

www.statistics.gov.uk/imps

• Students adjustment & migration modelling• Methodology papers• Impact assessments and validation• Further work

• Other Reports• Assessment of Demographic Rates• Review of QA Activities• Report on International Students in Communal

Establishments• Local Area Short-term Immigration Estimates• Report on change to use of Irish migration data

Page 104: Population and Migration Seeking your views Welcome and introductions Centre for Demography

How to respond

[email protected]

• Feedback questionnaire

• Responses supported by relevant information

• Questions for clarification

Page 105: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Feedback Received from QA Groups

• Local Insight Reference Panel (LIRP)• Tees Valley • London • Kent • Birmingham • Oxford • Bristol • Milton Keynes

• Expert Peer Review Group• Pete Boden (University of Leeds)• Paul Williamson (University of Liverpool)• James Raymer (University of Southampton)• Tony Champion (University of Newcastle)

Page 106: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Feedback from LIRP

• Overall• Fertility rates are a useful way of demonstrating impacts• Impacts are generally plausible but some changes more

difficult to interpret

• Migration Modelling• Issues with sources used in models• Scope for changing ‘intermediate geographies’• Need for more technical information

• Student Adjustment• Total population of students would provide useful context• Student adjustments look plausible in areas with large

student populations

Page 107: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Feedback from Expert Group

• Overall• Appreciated need for proposed improvements• Recommended a framework to consider migration • Regional immigration methods need further research

• Migration Modelling• Complexity / accuracy balance• Constraining model based estimates• Broadening models – across years and/or combining

immigration and emigration

• Student Adjustment• How census data was used in the adjustment• Clarification on double counting moves

• Short-term Migration• Definition used and seasonality in series

Page 108: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Refinements

• Migration Modelling• Intermediate geography?• Additional factors entered into models• Refinement of factors already entered

• Student Adjustment• Proportion of foreign students remaining in UK after studies• Imputation of term-time address• Area specific issues – Warwick/Coventry

• Final Impacts of Methodological changes• March/April

Page 109: Population and Migration Seeking your views Welcome and introductions Centre for Demography

2008-based Subnational Population Projections

• Trend based projections for England– covers years 2008 to 2033 (25 year period)– reflect indicative mid-2004 to mid-2008 population estimates– produced for GORs, LAs, PCOs and SHAs– consistent with National Population Projections

• Available for CLG and DH to use in resource allocation

• Incorporates improvements to projections methods

• Consultation on migration assumptions – 30 November 2009 to 18 January 2010

Page 110: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Improvements to Migration and Population Statistics

Indicative impacts

Centre for Demography

Page 111: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Indicative impacts

• Indicative impacts • How revisions have an effect• Distribution of revisions• An example of components of change• Areas with biggest Changes• Camden - a case study• Demonstrating an improvement

Page 112: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Indicative impacts

• Impacts are indicative– Data will change– Small changes in most areas– Some areas may change substantially

• Impacts will change because of– Further work– Results of the comments received– Final LA results

• summary will be published March/April 2010• full results will be published May 27 2010

Page 113: Population and Migration Seeking your views Welcome and introductions Centre for Demography

How the changes have an effect

Difference in 2008 population estimates ->

Cumulative change to migration data

Subnational Population Projections

Other Population Statistics

Other Statistics

Students Data

Internal Migration

International migration

Mid-year population estimates

Page 114: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Components of change

• Each revision +ve or –ve• Revisions interact• Changes data from 2002 to 2008

• Students adjustment to internal migration–Moves to university–Moves after university–Double counting adjustment

• International migration–Modelling in-migration–Updated out-migration model

• Other changes (small)

Page 115: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Distribution of impact across all local areas 2002 to 2008

Camden has been excluded from this chart

02

04

06

08

0N

umb

er o

f Loc

al A

utho

ritie

s

-6 -4 -2 0 2 4Percentage Impact

Page 116: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Cumulative percentage revision to mid-2008 population as a result of improvements to migration estimates

Page 117: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Cumulative revision to mid-2008 population as a result of improvements to migration estimates

Page 118: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Changes at local authority level

• Changing distribution of internal and international migration at LA level

• Biggest cause of change at LA level tends to be international migration re-distribution– But notable exceptions

• Cause of change shown in Table 2– In delegate packs.

Page 119: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Example – Manchester

Cumulative revisions 2002 to 2008

Centre for Demography

Page 120: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

Page 121: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Immigration

Revision

Original

Page 122: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Immigration

Revision

Original

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Emigration

Revision

Original

Page 123: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Immigration

Revision

Original

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Emigration

Revision

Original

Page 124: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Immigration

Revision

Original

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Emigration

Revision

Original

Page 125: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Inflow

Double Counting

Post study

To study

GP List

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Outf low

Double Counting

Post study

To study

GP List

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Immigration

Revision

Original

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Emigration

Revision

Original

Page 126: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Inflow

Double Counting

Post study

To study

GP List

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

Page 127: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500 -50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Inflow

Double Counting

Post study

To study

GP List

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Outflow

Double Counting

Post study

To study

GP List

Page 128: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Inflow

Double Counting

Post study

To study

GP List

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Outflow

Double Counting

Post study

To study

GP List

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

Page 129: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Manchester revisions

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Inflow

Double Counting

Post study

To study

GP List

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Outf low

Double Counting

Post study

To study

GP List

Revisions:Net student: 5,700Net international: -1,700Other Changes: 500Total revision: 4,500

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Immigration

Revision

Original

-50,000

0

50,000

100,000

150,000

200,000

250,000

300,000

Emigration

Revision

Original

Page 130: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Biggest 10 percentage upward revisions by local authority

Population, thousands Current mid-2008 population

Cumulative revision

2002 to ‘08

Percentage revision 2002 to ‘08

Annualised percentage revision

Hounslow

Boston

Southwark

Peterborough

Crawley

Harrow

WokingSouth Cambridgeshire

Barnet

Great Yarmouth

223

58

278

164

101

216

92

139

332

94

11

3

11

7

4

8

3

4

10

3

5.0

4.7

4.1

4.0

4.0

3.7

3.2

2.9

2.9

2.8

0.7

0.7

0.6

0.6

0.6

0.5

0.4

0.4

0.4

0.4Excludes City of London and Isles of Scilly

Page 131: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Biggest 10 percentage downward revisions by local authority

Population, thousands Current mid-2008 population

Cumulative revision 2002 to ‘08

Percentage revision2002 to ‘08

Annualised percentage revision

Camden

Cambridge

Elmbridge

Forest Heath

Oxford

S’th Northamptonshire

Durham

Ceredigion

Rutland

Brent

236

123

132

65

154

91

96

78

39

271

-20

-7

-7

-3

-7

-4

-4

-3

-2

-9

-8.5

-5.7

-5.2

-5.1

-4.8

-4.3

-4.2

-4.0

-3.9

-3.5

-1.1

-0.8

-0.7

-0.7

-0.7

-0.6

-0.6

-0.6

-0.5

-0.5

Page 132: Population and Migration Seeking your views Welcome and introductions Centre for Demography

National and regional indicative impact

population thousands Current mid-2008 population

Cumulative effect of change

Cumulative revision

2002 to ‘08

Annualised percentage revision

England and Wales

England

North East

North West

Yorkshire & Humber

East Midlands

West Midlands

East

London

South East

South West

Wales

54,440

51,446

2,575

6,876

5,213

4,433

5,411

5,729

7,620

8,380

5,209

2,993

10

13

-1

1

1

-5

-4

-16

58

-16

-4

--3

0.02

0.03

-0.04

0.01

0.02

-0.11

-0.07

-0.28

0.76

-0.20

-0.08

-0.11

0.00

0.00

-0.01

0.00

0.00

-0.02

-0.01

-0.04

0.11

-0.03

-0.01

-0.02

Page 133: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Formal Tables

• Summary Tables– Table 1: Total impact by year

• Table 1b: Biggest 20 increases, mid-2008• Table 1c: Biggest 20 decreases, mid-2008

– Table 2: Cumulative effect by adjustment, mid-2008• Detailed

– Table 3: Annual and cumulative students effect– Table 4: Annual and cumulative effect of net international migration– Table 5: Annual and cumulative effect of other changes

• Very Detailed– Table 6: Net and gross students effects, by type of flow

• (to study, post study, and counter adj.)– Table 7: Net and gross international migration– Table 8: Size of increase in student flows, by type of flow

• Context– Table 9: Short-term and long-term international immigrants, mid-2007

• Tables are by LA, county, GOR, etc, and for all years mid-2002 to mid-2008 (except where single year is indicated).

• Some material by age and sex available on request.

Page 134: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Charts Available

• All charts are by local authority

• Student adjustment and internal migration– Adjustment as percentage of student flows

• International migration– Net

– In

– Out

• Total change and total effect

• Total fertility rate

Page 135: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Case Study - Camden

Centre for Demography

Page 136: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden Births

Births in Camden 2001 to 2008

2600

2700

2800

2900

3000

3100

3200

2001 2002 2003 2004 2005 2006 2007 2008

Page 137: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: Total Fertility Rate (TFR)

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

2001 2002 2003 2004 2005 2006 2007 2008

To

tal F

ertil

ity R

ate

(TF

R)

TFR published

Page 138: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: Total Fertility Rate (TFR)

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

2001 2002 2003 2004 2005 2006 2007 2008

To

tal F

ert

ility

Ra

te (

TF

R)

TFR published

TFR incorporatingonly studentadjustment revision

Page 139: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: Total Fertility Rate (TFR)

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

2001 2002 2003 2004 2005 2006 2007 2008

To

tal

Fer

tili

ty R

ate

(TF

R)

TFR published

TFR incorporatingonly studentadjustment revision

TFR onlyinternationalmigration revision

Page 140: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: Total Fertility Rate (TFR)

1.10

1.15

1.20

1.25

1.30

1.35

1.40

1.45

1.50

2001 2002 2003 2004 2005 2006 2007 2008

To

tal F

ert

ility

Ra

te (

TF

R)

TFR published

TFR revised -including allrevisions

TFR incorporatingonly studentadjustment revision

TFR onlyinternationalmigration revision

Page 141: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: Annual and cumulative population change

-25,000

-20,000

-15,000

-10,000

-5,000

0

2001 2002 2003 2004 2005 2006 2007 2008

Ch

an

ge

in m

id-y

ea

r p

op

ula

tio

n e

sti

ma

te

Annual revision

Cumulative revision

Page 142: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: total mid-year population estimates

180,000

190,000

200,000

210,000

220,000

230,000

240,000

2002 2003 2004 2005 2006 2007 2008

Mid

-yea

r p

op

ula

tion

est

imat

e

Published mid-yearpopulation estimate

Revised indicativemid-year populationestimate

Page 143: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes: international migration inflow

-4,000

-2,000

0

2,000

4,000

6,000

8,000

10,000

12,000

2002 2003 2004 2005 2006 2007 2008Inte

rnat

ion

al m

igra

tion

inflo

w

Internationalmigration inflow -current

Internationalmigration inflow -revised

Inflow revision -migration modelling

Page 144: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Impact of proposed changes on internal migration: Student adjustment

-3,500

-3,000

-2,500

-2,000

-1,500

-1,000

-500

0

500

2002 2003 2004 2005 2006 2007 2008

Inte

rnal

Mig

ran

ts

Internal migration -current methods

Internal migration -after revision fromstudent adjustment

Revision - resultingfrom studentadjustment

Page 145: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden – student revisionstotal 2002 to 2008

Inflow Outflow Balance

To study

After study

Double counting

2,300

3,000

-1,700

1,000

3,300

-1,600

1,300

-300

-200

Net 3,700 2,700 800

Page 146: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Camden

Percentage of student flows adjusted

-100

-80

-60

-40

-20

0

20

40

60

80

100

Per

cen

tag

e o

f st

ud

ent

flo

ws

adju

sted

Student moves to study Student moves after study

Blue bars indicate f low s to the area

Red bars indicate f low s away from the area

From domicileresidence

To study residence

From studyresidence

To first destinationresidence

Page 147: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Demonstrating an improvement

Centre for Demography

Page 148: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Issues to be addressed by the new methodology…

• Some young people, particularly young men, not changing their GP registration soon after they move

• Students a sub-set of young people, who necessarily cluster in certain areas of the country

• Affects estimation of students moving to university and moving away after their studies

• Some encouragement to change GP registration at start of studies, but no encouragement when students leave

Page 149: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Solution: what’s new?

• Higher Education Statistics Agency (HESA) data

• Data on all HE students

• New term-time postcode detail collected by HESA for all institutions from 2007/08 academic year

• New detail received March 2009

Page 150: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Modelling in-migration

• Current method uses 2001 Census data to distribute to LA level

• Clear changes in migration trends since 2001

e.g. EU accession

• Concept proved with introduction of local authority out-migration models in 2007

Page 151: Population and Migration Seeking your views Welcome and introductions Centre for Demography

What modelling achieves

• Improves timeliness at LA level

• Potential use of administrative data

• GP registrations (Flag 4s)

• National Insurance Number (NINo) allocations to overseas nationals

• Annually updated counts available

• Provide counts at local authority level

Page 152: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Demonstrating an improved methodology• Student adjustment uses data from an independent source that

gives actual student moves missed by patient registers• Student adjustments after study

– Carefully verified by other data– Based on known student numbers– Using distributions which have been carefully corroborated

• International immigration estimation model– Uses updatable sources to distribute instead of fixed 2001 Census

data– Model makes use of the best features from a range of administrative

and other sources– Minimises the impact of definitional issues with administrative sources

• International emigration model– Updated to reflect comments made previously– More technically robust– Better reflects data structure– Incorporates improved immigration data

Page 153: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Demonstrating an improvement

• Demographic analysis shows improvement in key areas (e.g. Camden)

• Analysis of student areas shows much more plausible age profiles after student adjustment (see June Roadshow slides)

Page 154: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Indicative results: Ceredigion mid 2007 population

0

500

1,000

1,500

2,000

2,500

3,000

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

single year of age, 10-35

po

pu

lati

on

original

adjusted

adj+cadj3yrlag

2001 pattern

mid-2007

Page 155: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Quality assuring the improvement

• Giving all users a chance to comment• Extensive and rigorous internal quality

reviews• Using local insight to:

– Develop and refine methods– Sense check the results

• Extensive peer review

Page 156: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Short-term ImmigrationEstimates at Local Area Level

Centre for Demography

Page 157: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Introduction

• Local Authority level short-term immigration estimates published for first time in October 2009 as part of a research report

• Estimates are available for:• The year to mid-2007• In-flows only• Moves made for between 1 and 12 months• All reasons for visit (with a worker/non-worker breakdown

provided)

• England & Wales level estimates previously published for mid-2004 to mid-2007

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Total Short-term visits: Top Ten Areas

Rank Local Authority Estimate

1 Westminster 62,800

2 Manchester 35,900

3 Birmingham 33,000

4 Ealing 29,200

5 Camden 28,000

6 Barnet 23,500

7 Brent 21,600

8 Southwark 21,300

9 Oxford 19,500

10 Wandsworth 18,800

Page 159: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Research Report

• Sets out detailed methodology• Data used• Differences between methods for workers and non-

workers• How final approach was chosen

• Summarises validation work• Statistical assessment of model validity/stability• Assessment by Reason for Visit• Assessment of areas with largest worker estimates• Use of HESA data for international short-term students

Page 160: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Regional Level Immigration Estimates

Region Estimate % of England & Wales Total

England 1,295,000 97%

North East 28,000 2%

North West 120,000 9%

Yorkshire & The Humber 85,000 6%

East Midlands 80,000 6%

West Midlands 97,000 7%

East 113,000 8%

London 480,000 36%

South-East 199,000 15%

South-West 92,000 7%

Wales 40,000 3%

Page 161: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Reason for Visit

Reason For Visit Estimate % of England & Wales Total

Work 175,000 13%

Study 199,000 15%

Visiting Friends or Family 538,000 40%

Join/Accompany 11,000 1%

Business 120,000 9%

Holiday 214,000 16%

Other 77,000 6%

Total 1,334,000 100%

Page 162: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Short-term Immigrant Workers: Top Ten Areas

Rank Local Authority Estimate

1 Newham 4,400

2 Brent 4,300

3 Ealing 4,000

4 Birmingham 3,600

5 Manchester 3,100

6 Haringey 3,100

7 Waltham Forest 2,900

8 Tower Hamlets 2,800

9 Hounslow 2,700

10 Wandsworth 2,600

Page 163: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Short-term International Students: Top Ten Areas from HESA data

Local Authority HESA Estimate of Short-term

Immigrant Students

% of Short-term Immigration

Estimate

Camden 5,200 19%

Manchester 4,000 11%

Cardiff 3,900 32%

Islington 3,900 25%

Newham 3,800 21%

Newcastle upon Tyne 3,800 40%

Coventry 3,200 30%

Birmingham 2,900 9%

Tower Hamlets 2,800 17%

Leeds 2,800 15%

Page 164: Population and Migration Seeking your views Welcome and introductions Centre for Demography

Conclusions

• Current methodology and estimates are initial work

• Feedback is being sought from users to inform further research

• Aim to publish mid-2008 local authority estimates in May 2010