Small Area Estimation: Data Provision for Smarter Local Policymaking
Submitting Institution
University of SouthamptonUnit of Assessment
Mathematical SciencesSummary Impact Type
EconomicResearch Subject Area(s)
Economics: Applied Economics, Econometrics
Summary of the impact
Southampton statisticians have made a valuable contribution to government
policy formulation across the UK and further afield to areas of North
America and Europe. Novel methods for delivering more accurate estimates
of socio-economic indicators at neighbourhood level have given local
authorities, national government agencies and MPs the tools to implement
more effective policies designed to assist the poorest communities and
strengthen community cohesion. The UK's Office for National Statistics
(ONS) has described Southampton's contribution as `a breakthrough', while
the Mexican government agency, CONEVAL, regards this work as `the most
prestigious' of its kind.
Underpinning research
Surveys are often designed to provide estimates of social and economic
indicators at a population level. For example the Labour Force Survey,
conducted by ONS, is a large household survey which provides the official
measures of employment and unemployment in the UK. Policymakers at a local
level, for example local authorities or MPs serving their constituents,
require a much more detailed picture than is provided by national
estimates. However, obtaining accurate values for small geographical areas
— small area estimation — is problematic as the survey sample size is
usually too small to yield reliable direct estimates. Statistics are
instead based on `indirect' estimates that use information from other
areas with similar characteristics to the region under the microscope.
Statisticians at the University of Southampton have been developing novel
statistical methodologies of small area estimation since 2001 to produce
more accurate estimates of key social and economic indicators for more
effective local policymaking. Indicators that have been a particular focus
of the research are: (a) average household income and average business
turnover; (b) complex poverty indicators (head count ratio, poverty gap
and poverty severity); (c) proportions of unemployed, employed and
inactive individuals and corresponding measures of precision quantified by
mean squared error (MSE) estimators.
The first phase (2001-2004) of this research was carried out as part of
the EU's EURAREA (Enhancing Small Area Estimation Techniques to meet
European Needs) project. The aim of the project was to provide National
Statistical Institutes across Europe with a basis for deciding whether,
and how, to apply small area estimation techniques in the production of
official statistics. Professor Ray Chambers (1995-2006) and Dr Ayoub Saei
(Research Fellow, 2002-2006), led the development of techniques for
deriving point and MSE estimates of labour force activity at small area
level [3.1]. Local authorities in the UK had previously found
accurate unemployment information almost impossible to obtain; the
unreliability of estimates resulted in only about a quarter of the annual
estimates of unemployment in 1999/2000 qualifying for publication.
From 2003 to 2006, funded by an ESRC grant, Chambers and Dr Nikos
Tzavidis (Research Fellow, 2003-2005; Senior Lecturer, 2010-present)
developed multi-quantile (M-quantile) models for small area estimation of
averages and totals [3.2, 3.3]. Tzavidis was subsequently PI on a
project that extended this work to methodologies for estimating poverty
indicators and distribution functions at small area level. This latter
strand of research, from 2008 to 2011, was part of the EU's SAMPLE (Small
Area Methodologies for Poverty and Living Condition Estimates) project,
which identified new indicators and models for inequality and poverty [3.4-3.6].
The research carried out in the course of the ESRC-funded work and the
SAMPLE project resulted in the development of innovative statistical
methodologies in small area estimation. Chambers and Tzavidis' 2006 paper
[3.2], published in Biometrika, was key to the development of this
field and is still regularly cited (117 citations to 31/10/13 — Google
Scholar). The Office for National Statistics (ONS) was able to build on
the methodology to publish improved unemployment figures at local
authority level, first as experimental statistics and then as official
national statistics.
All new methodologies were developed with users' needs in mind and
supported by easy-to-use software. This work led to significant
international interest in Europe (e.g. Eurostat EURAREA Project, Portugal,
the Ukraine) and outside (e.g. Australian Bureau of Statistics, Statistics
New Zealand, Korea). In particular, this approach, coupled with contracts
with key non-academic organisations such as the ONS, Mexico's National
Council for the Evaluation of Social Development Policy (CONEVAL) and the
Netherlands' Centraal Bureau voor de Statistiek, has widened the influence
of Southampton's pioneering techniques.
References to the research
Publications:
3.1 (*) Molina, I, Saei, A, and Lombardia, MJ (2007): Small Area
Estimates of Labour Force Participation Under a Multinomial Logit Mixed
Model, Journal of the Royal Statistical Society, Series A, 170, 975-1000
3.2 (*) Chambers, R, and Tzavidis, N (2006): M-Quantile Models for
Small Area Estimation, Biometrika, 93, 255-268
3.3 (*) Chambers, R, Chandra, H, Salvati, N, and Tzavidis, N
(2013): Outlier Robust Small Area Estimation, Journal of the Royal
Statistical Society: Series B (DOI: 10.1111/rssb.12019)
3.4 Tzavidis, N, Marchetti, S, and Chambers, R (2010): Robust
Prediction of Small Area Means and Distributions, Australian & New
Zealand Journal of Statistics, 52, 167-186
3.5 Chambers, R, Chandra, H, and Tzavidis, N (2011): On
Bias-Robust Mean Squared Error Estimation for Pseudo-Linear Small Area
Estimators, Survey Methodology, 37 (2), 153-170
3.6 Marchetti, S, Tzavidis, N, and Pratesi, M (2011):
Non-Parametric Bootstrap Mean Squared Error Estimation for M-Quantile
Estimators of Small Area Averages, Quantiles and Poverty Indicators,
Computational Statistics and Data Analysis, 56, (10), 2889-2902
(*) These references best indicate the quality of the underpinning
research.
Grants:
3.G1 EURAREA (Enhancing Small Area Estimation Techniques to meet
European Needs), Framework Programme 5, 2001-2004, Professor Ray Chambers
[€1,833,781]
3.G2 Multi-Quantile Models for Small Area Estimation, ESRC,
2003-2006, Professor Ray Chambers [£164,465.93]
3.G3 SAMPLE (Small Area Methodologies for Poverty and Living
Condition Estimates), Framework Programme 7, 2008-2011, Dr Nikos Tzavidis
(PI for University of Southampton) [€778,000]
3.G4 Office for National Statistics, Methodology Contract
(contract number PU-10/0141), 2010-2015, University of Southampton
[minimum amount: £135,000 x 5 years]
3.G5 Netherlands Central Bureau of Statistics, Methodology
Contract, 2010-2011 [€99,900]
Details of the impact
Decision makers tasked with devising and implementing effective and
inclusive socio-economic policies need as much information as possible.
Novel methodologies of small area estimation developed by researchers at
Southampton have provided policymakers, both in the UK and
internationally, with reliable data ranging from average household income
to unemployment figures right down to neighbourhood level. In particular,
the Southampton research has allowed small-area estimates of employment
indicators and income indicators to be derived from the Labour Force
Survey, the largest household survey in the UK, and the Family Resources
Survey, respectively.
Southampton's long-time collaboration with the ONS has proved essential
in providing this range of disaggregated data to the Department for Work
and Pensions (DWP) and local authorities around the UK. Dr Alan Taylor,
Head of the ONS' Small Area Team, has described Southampton's work in this
field as `a recognised breakthrough' [5.1]. He said: `In my
experience great research can often lead to academic papers but not get
translated into outputs. Our collaboration [with Southampton] has led to
significant improvements in ONS small area estimates of income and
unemployment and [has] led the world in model-based estimation.'
The ONS' own National Accounts Team and Labour Market Division have
relied upon the estimates to answer enquiries from local authorities,
policy advisers, government departments and academics. The ONS has
reported that demand for small area estimates has been `strong' [5.1]
and that users have drawn on them for a variety of socio-economic
purposes. An analysis conducted by the ONS in 2012 concluded: `Without
these estimates valuable insights into the differences between small
area geographies would be lost... Users would need to look around for an
alternative and less suitable source. In particular, a number of
parliamentary questions would have to be answered at higher geographies.'
[5.1]
Southampton's success in producing sets of local authority-level
estimates of labour force activity has proved invaluable for MPs in
serving the needs of their constituents. A letter [5.2] written to
the ONS in 2005 by the Chief Librarian for the House of Commons, John
Pullinger, reflects the significance of these data, obtained using
Southampton-designed methodologies. Pullinger stressed the importance of
making a common set of key labour force indicators — for example
Jobseekers Allowance claimants as a proportion of the constituency's
working age population — available to serving MPs, something which is only
possible as a result of this research. The model-based estimates of mean
income developed by Southampton researchers helped the ONS plug a gap in
its national statistics provision enabling the ONS to supply the DWP with
small area income estimates.
Local authorities are the main users of these estimates. The Greater
London Authority used small area estimates in its 2010 Focus on London
report, Income and Spending at Home [5.3], which compared
income at both individual and household level across the capital. This was
a key input in the Mayor of London's Outer London Commission Report
[5.4], which analysed the challenges and opportunities facing the
outer London economy. This in turn was an important source of information
for developing new policies in housing and transport proposed in the new
London plan (2011), the strategic development plan [5.5] for the
capital up to 2031.
Another local authority, the London Borough of Newham, used the estimates
in their Information Management System allowing members of the public to
summarise and map data via data interrogation tools on the borough's
website. Newham further used the data to answer queries from members of
the public and from other local authority officers. Users, including the
DWP, stated that without these estimates valuable insights into the
differences between small area geographies would be lost [5.1].
The impact of Southampton's research has extended overseas. In 2009, the
Mexican government agency, CONEVAL, sought the University's help in
producing estimates of income and social rights deprivation in Mexican
municipalities. Methodologies developed by the Southampton team since 2001
have allowed CONEVAL to measure access to health, education and food at
neighbourhood level as part of its brief to define, identify and measure
poverty across the country. Dr Aparicio Jimenez, CONEVAL's Poverty
Analysis Director, said: `With this research, the poorest
municipalities in Mexico can be identified. With this valuable
information, the federal government, the National Congress, federal
states and municipalities will be able to design more effective social
programmes.' CONEVAL described Southampton's research as `the most
prestigious' of its kind [5.6].
A year later Southampton's modelling methods enabled the Netherlands'
Centraal Bureau voor de Statistiek (CBS) to deliver more accurate
estimates of business turnover, which have guided policy changes at a
national level [5.7]. CBS reported that Southampton's
methodologies proved superior to other small area estimation approaches
`in several situations' [5.8].
Sources to corroborate the impact
5.1 Head of Small Area Team, Office for National Statistics.
5.2 Letter by Librarian of House of Commons to Director, Labour
Market Division, Office for National Statistics).
5.3 http://data.london.gov.uk/documents/FocusOnLondon2010-income-and-spending.pdf
(The Head of the Small Area Team at ONS can confirm the use of the
Southampton research in producing this data)
5.4 http://static.london.gov.uk/olc/docs/final-report.pdf
(This document makes substantial use of the data in 5.3)
5.5 http://www.london.gov.uk/priorities/planning/london-plan
(This document builds on 5.4 and also uses the data in 5.3)
5.6 Letter/Email about the value of Southampton/CONEVAL
collaboration (2012) by the Director of Poverty Analysis, CONEVAL, Mexico.
5.7 CBS discussion paper: Small Area Estimation of Turnover of the
Structural Business Survey (2012): http://www.cbs.nl/NR/rdonlyres/2FC2BE74-1AF0-462A-9C76-9C836EA07655/0/201203x10pub.pdf
5.8 The Researcher of Netherland Centraal Bureau voor de
Statistiek (CBS), Division of Methodology and Quality can corroborate the
use of the code developed by Southampton for implementing the methods.