Opportunities and Challenges of the 2011 Census: A view from academia

Tony Championtony.champion@ncl.ac.uk

Paper for the TWRI Policy & Research Conference ‘Making best use of the 2011 Census’, St William’s College, York, 5 October 2012

Introduction 1

Academic users of the Population Census cover a wide range of interests, but these can be summarised under three main sets of purposes:

1) Deriving descriptive contextual information on populations of interest;

2) Analysing data to improve our understanding of UK society and how it is evolving, often using advanced quantitative techniques;

3) Benchmarking other surveys to ensure that they represent the total population of an area.

And these are not just for ‘academic purposes’: much work is also carried out under contract for local and central government, research foundations, and the private and third sectors

Introduction 2

Features of the census that are most prized by academics (according to submissions to the Science & Technology Committee Inquiry into the Census and Social Science and to the ONS’s Beyond 2011 Public Consultation on User Requirements) include:- opportunities for multivariate analysis- fine-grained geography- high degree of accuracy even at small-area level- ability to study change between censuses

This is reflected in their high usage of other census datasets as well as Area Tables: e.g. Origin-Destination Tables, Samples of Anonymised Records, Longitudinal Studies

The rest of this paper presents examples of benefiting from these census qualities in my previous research on these datasets, then looks forward to using the 2011 outputs

Examples from Area Tables Example 1: from Key Statistics

The GB local authorities with the 10 highest and lowest proportions of migrant residents, 2001

Rank Highest % Rank Lowest %

1 Oxford 25.6 408 East Dunbartonshire 7.32 Cambridge 24.9 407 Havering 7.73 City of London 23.0 406 East Renfrewshire 7.94 Westminster 22.9 405 Knowsley 8.05 Wandsworth 21.0 404 Rochford 8.06 Camden 20.6 403 North East Derbyshire 8.07 Hammersmith and Fulham 20.1 402 Dudley 8.08 Richmondshire 19.7 401 South Staffordshire 8.19 Kensington and Chelsea 19.4 400 Castle Point 8.1

10 Manchester 19.3 399 Ellesmere Port and Neston 8.1

Example 2: from Area TableNet within-UK migration rate, age groups, for Rural Towns and Other Rural, England

-10

-8

-6

-4

-2

0

2

4

0-15 16-19 20-24 25-29 30-44 45-59 60-74 75+

% r

esid

ents

in

ag

e g

rou

p

Rural Towns Villages & scattered

Example 3: from Commissioned Area Table

Districts most affected by the out-migration of full-time students (% out-migrants aged 16-74)

Darkest = 20-44%

Example 4: From several censuses Population change by local labour market area types, 1901-11 to 1981-91

-10

-5

0

5

10

15

1901-11 1911-21 1921-31 1931-51 1951-61 1961-71 1971-81 1981-91

% f

or

pe

rio

d (

NB

. 1

93

1-5

1=

20

yrs

)

Large City Middle-sized City Small City Rural Areas

Examples from the SARsThe Samples of Anonymised Records 2001 comprise a

suite of datasets: 1% Household SAR & CAMS, 3% Individual SAR & CAMS, and 5% Small Area Microdata [CAMS = Controlled Access Microdata Sample]

The SARs allows any combination of crosstabulations including some not available anywhere in Area Tables: e.g. it is the only standard census dataset where commuting and migration variables can be related

CAMS is extremely rich in detail on the characteristics and geography (e.g. LAD of address currently and one year ago and LAD of workplace)

Examples: (1) Age distribution (single-year) of one-year migrants by distance of move; (2) Length of commute by type of LAD and one-year-migrant status …

Example from the SARs 1:Age profile of within-UK migrants moving <3 km and 50+ km

x

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95+

Age at census (years)

% a

ll ag

es

<3 km 50+ km

Example from the SARs 2:Proportion commuting 20km+, by urban/rural district typecomparing recent in-migrants with non-migrants

0.0 5.0 10.0 15.0 20.0 25.0

England

Major Urban

Large Urban

Other Urban

Significant Rural

Rural-50

Rural-80

% commuting 20km+

Non-migrant

Migrant

Examples from O/D Statistics

Origin & Destination Statistics comprised two main sets in 2001: Special Workplace Statistics and Special Migration Statistics (plus Special Travel Statistics in Scotland)

One major use of SWS has been for Travel to Work Areas (TTWA) & other regionalisations like City Regions (CRs) by Mike Coombes et al (Newcastle University)

In recent work Mike and I compared commuting patterns across 3 censuses to look for any tendency for ‘Pennine England’ to become a more integrated polycentric region

One use of the SMS has been to track attraction and retention of migrants by skill group, 2001, seeing how other large Cities compare with and relate to London …

Pennine England: 5 Cities & City Regions

Cities are defined as Core City admin. areas; in total the City Regions include 44 other local admin. areas (identified by meta-analysis of other definitions)

Commuting in Pennine England:Is there increasing integration between the 5 City Regions?

1981 1991 2001 2001-1981

Between-CR commuters 121,150 158,610 222,141 +100,991

Between-CR as % of:

All workers 3.0 4.1 5.4 +2.4

Inter-zonal commuters 12.5 15.0 17.6 +5.1

People commuting between the 5 City Regions are becoming a:

(1) larger share of all those who live & work in Pennine England

(2) larger share of those commuting between any of the 49 zone pairs

Modelling is then used to see whether the deterrence effect of CR

boundaries has reduced (results not shown here)

Migration for Larger Cities 1:27 cities ranked by in/out ratio for high-status workers

27 cities ranked by in/out ratios for migration beyond the City Region: Higher Managerial & Professional MGRPs

0.4 0.6 0.8 1.0 1.2 1.4 1.6

LondonBrighton

DerbyNorthampton

EdinburghReading

ManchesterBristolLeeds

NorwichSouthampton

PrestonPortsmouth

BradfordBirmingham

GlasgowPlymouth

CardiffNewcastleLiverpoolLeicester

MiddlesbrouNottingham

HullSheffield

StokeCoventry

in/out ratio

Migration for Larger Cities 2: In/out ratio for exchanges with London by skill group

PUAs of 8 Core Cities: in/out ratio migration exchanges with London PUA, 2000-2001, for classified MGRPs by NS-SeC grouping at Census

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Birmingham Manchester Liverpool Newcastle Nottingham Sheffield Leeds Bristol

in/o

ut

rati

o

Higher M&P Lower M&P Intermediate Low Skill

Examples from the ONS-LS The ONS Longitudinal Study was set up in the 1970s

mainly for relating death events and notifiable diseases to Census-derived socio-demographic characteristics

It comprises a ca-1% sample of people’s anonymised records linked across the 1971 & following censuses, allowing tracking of people’s social & spatial mobility

Extremely powerful source for following people’s life courses and relating their several ‘biographies’ to each other, e.g. re family/household, occupation, whereabouts

Examples: (1) Working career progression, e.g. chance of rising from White Collar Non-core to Core 1991-2001, by place of residence; (2) Length of stay in the ‘escalator region’ of SE England after migrating there 1966-71 …

Example from ONS-LS 1 (a):

Probability of WC Non-core 1991 becoming WC Core 2001: all stayers of 10 City Regions (ranked)

x

6.0 8.0 10.0 12.0 14.0 16.0 18.0

London

Manchester

Leicester

Sheffield

Leeds

Birmingham

Nottingham

Bristol

Newcastle

Liverpool

Probability (%)

London = 15.8

Weighted average for 9 non-London CRs = 12.2

All zone stayers in

England & Wales = 13.1

Liverpool is 68% of London

Example from ONS-LS 1 (b):

Probability of WC Non-core starters becoming WC Core by end of decade (out of all those still in work, stayers only)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

1971-1981 1981-1991 1991-2001

Pro

ba

bil

ity

(%

)

London 9 other CRs Rest of E&W

Example from ONS-LS 2: Movements between Rest of England & Wales (REW) and South East (SE) of the 1966-71 REW-to-SE migration cohort

The ‘escalator region’ hypothesis has it that people moving to the South East early in their working lives (most of the 3,136) will stay there for most of their careers to benefit from its better prospects, but many had departed within 15 years of arriving.

Period In REW at start of period

From REW to

SE

From SE to REW

In REW at end of period

In SE at end of period

%

1966-1971 3136 3136 n/a 0 3136 100.0

1971-1981 0 n/a 1098 1098 2038 65.0

1981-1991 1098 104 287 1281 1855 59.2

1991-2001 1281 61 195 1415 1721 54.9

Plans for 2011 Census analysis 1

Once again, merely a personal research agenda, which will no doubt be much multiplied across the academic community

Plans include:• Using the Area Tables to monitor the ‘state of British cities’,

building on the demographic and economic analyses carried out for the English SOCR

• Using the ODS to update and extend the previous work on the changing nature of polycentric urban regions

• Using the ONS LS to probe further the relationships between social and spatial mobility, with a particular focus on the experience of immigrants (by year of arrival in UK)

• Using the Area Tables and SARs to explore the results flowing from other ‘new’ questions on, e.g., visitors, second addresses and alternative population bases

Plans for 2011 Census analysis 2

• Using SARs and LSs to test for post-1970 change in within-UK migration rates by population sub-group

• Responding to opportunities for providing info to central and local government, etc., for planning & policy purposes

• Trying to ensure as much benefit as possible from the 2011 Census outputs to help make the case for a 2021 Census