The use of multilevel statistical modelling has led to improved evidence-based policy making in education and other sectors
Submitting Institution
University of BristolUnit of Assessment
Mathematical SciencesSummary Impact Type
SocietalResearch Subject Area(s)
Mathematical Sciences: Statistics
Information and Computing Sciences: Computation Theory and Mathematics, Information Systems
Summary of the impact
Since 2008, statistical research at the University of Bristol has
significantly influenced policies, practices and tools aimed at evaluating
and promoting the quality of institutional and student learning in the
education sector in the UK and internationally. These developments have
also spread beyond the education sector and influence the inferential
methods employed across government and other sectors. The underpinning
research develops methodologies and a much-used suite of associated
software packages that allows effective inference from complicated data
structures, which are not well-modelled using traditional statistical
techniques that assume homogeneity across observational units. The ability
to analyse complicated data (such as pupil performance measures when
measured alongside school, classroom, context and community factors) has
resulted in a significant transformation of government and institutional
policies and their practices in the UK, and recommendations in
Organisation for Economic Co-operation and Development (OECD) policy
documents. These techniques for transforming complex data into useful
evidence are well-used across the UK civil service, with consequent policy
shifts in areas such as higher education admissions and the REF2014
equality and diversity criteria.
Underpinning research
Multilevel statistical modelling, a sophisticated methodological approach
to data analysis, has been developed at the University of Bristol since
2005. This statistical technique is crucial in analyses of complex data
sets that have non-trivial geographical and/or temporal components, data
structures which could cause dangerous confusion if analysed using more
basic statistical techniques. The impact of these approaches has been
maximised through deployment of research such as [2] in new versions of
the hugely popular MLwiN statistical software package, along with new
software such as REALCOM-impute [3] which carries out multiple imputation
of missing data in the context of a multilevel model, MLPowSim to perform
sample size calculations for multilevel modelling, and Stat-JR, an
innovative software environment for promoting interactive statistical
modelling. Recent research has focussed on developing inference methods
for realistically complex multilevel models, and developing an
understanding of the computational methodologies required to fit complex
models to large data sets, such as those obtained from national level data
collection of, for example, pupil test scores and university applications.
Novel statistical methodology underpinning the impact:
- Introduction of re-parameterisation techniques within Markov chain
Monte Carlo (MCMC) algorithms for fitting multi-level models, allowing
the statistical analyses to become sufficiently efficient to be carried
out on significantly larger and more complex data structures [2].
- Simulation-based graphical approaches to communicating statistical
uncertainty of group effects in multilevel models [6], which are
otherwise difficult to interpret and communicate.
- Novel multilevel modelling formulations for complex non-hierarchical
data structures [5]. This type of data set arises, for example, when
effects of both schools and neighbourhoods are to be taken into account
in models of pupil performance.
- Advanced multilevel modelling for analysis of longitudinal data with
multilevel structure. In particular when the observational units change,
but the grouping units do not, such as clinical outcomes in a hospital
in successive time periods, or pupils in a school in successive years
[6].
- Multilevel statistical techniques for modelling multivariate data with
different response types at several levels, and handling correlated
measurement and misclassification errors [4].
Novel computational implementations underpinning the impact:
- The general computational capabilities of MLwiN, and the MCMC module
in particular [1], have been updated to enable efficient inference to be
carried out with complex models and large data sets. Key parts of this
update, which have been in versions of MLwiN since 2.13 (released in
August 2009), are based on the techniques of [2].
- Production of three new software packages: REALCOM-impute [3], to
allow imputation of missing data; MLPowSim, to perform sample size
calculations within the multi-level modelling framework; and Stat-JR, a
software environment for promoting interactive statistical modelling.
The team that carried out the research described above moved to Bristol
in 2005 (Goldstein, Prof. of Social Statistics, Steele, Prof. of Social
Statistics, and Rasbash, Prof. of Computational Statistics), 2007 (Browne,
Prof. of Biostatistics) and 2009 (Leckie, Senior Lecturer in Social
Statistics).
References to the research
*[2] Browne, W.J., Steele F., Golalizadeh, M., and Green M.J. (2009) The
use of simple reparameterizations to improve the efficiency of Markov
chain Monte Carlo estimation for multilevel models with applications to
discrete time survival models. Journal of Royal Statistical Society,
A, 172, 579-598. DOI:10.1111/j.1467-985X.2009.00586.x
[4] Goldstein, H., Kounali, D. and Robinson, A. (2008) Modelling
measurement errors and category misclassifications in multilevel models. Statistical
Modelling, 8, 243-261. DOI:10.1177/1471082X0800800302
*[5] Leckie, G. (2009) The complexity of school and neighbourhood effects
and movements of pupils on school differences in models of educational
achievement. Journal of the Royal Statistical Society, A, 172,
537-554. DOI:10.1111/j.1467-985X.2008.00577.x
*[6] Leckie, G. and Goldstein, H. (2009) The limitations of using school
league tables to inform school choice. Journal of the Royal
Statistical Society, A, 172, 835-851.
DOI:10.1111/j.1467-985X.2009.00597.x
* references that best indicate the quality of the underpinning research.
Details of the impact
Since 1 Jan 2008, MLwiN has been purchased by 613 non-academic individual
users and 75 organisations (67 site licenses for 50 users, and 8 for 250
users). It has also been downloaded for free by 3,846 UK academics, and
purchased by 5,518 overseas academics. The Bristol Centre for Multilevel
Modelling website is widely acknowledged as the premier resource for
research and training in multilevel modelling, with around 1,100
page-loads and 360 unique visitors per day (65% of whom are from outside
the UK). The on-line Learning Environment for Multilevel Modelling
(LEMMA), launched in April 2008 as part of the Economic and Social
Research Council National Centre for Research Methods, now has around
10,600 registered users, of which 70% are international and 14% are
non-academic. The sheer number of users demonstrates the reach and
significance of the underpinning research [1-3]. Non-academic users of
Centre software, and hence the underlying research, include the World
Health Organisation, Statistics Canada, Statistics Norway, Netherlands
Central Bureau of Statistics, the UK Departments for Education, Health,
and Work and Pensions, the Scottish Executive, the Office for National
Statistics and the Higher Education Funding Council for England. Analyses
by these bodies, and others, as well as by the academic users of the
software, have significant impact on society; we focus on three specific
areas.
A. Impact on UK and international policy and public awareness
relating to measuring educational effectiveness and school performance
Improved school evaluation policies: In the UK, Goldstein's
multilevel modelling framework (including, for example, [4-6]) has
provided the statistical toolkit which has provided evidence to inform and
influence key national policies related to school evaluation such as: the
utility of school self-evaluation, national pupil databases,
contextualised value-added (CVA) measures of school performance, and
separate value-added measures for different student groups (introduced by
the Department for Education (DfE) 2011). The research has also promoted
the use and understanding of a wider range of outcomes and measures by
DfE, the Department for Children, School and Families, the Office for
Standards in Education, Children's Services and Skills (Ofsted) and the
Learning and Skills Council [a]. MLwiN is currently used within DfE to
calculate published measures of CVA school performance, an integral part
of the Ofsted school inspection process, and also to construct the
Learning Achievement Tracker, a new tool for schools and further education
colleges to appreciate progress made by students since the end of
compulsory schooling [b]. In particular "MLwiN allows ... complex
cross-classified multilevel structures, and these, using, in the main,
MCMC methods, were used to inform the DfE about the variations in pupil
performance associated statistically with their social background and
school attended," [b] which demonstrates that research items [1,2,5] are
having significant impact in this area.
Public understanding of league tables: The statistical research
carried out by [6] demonstrates the limitations of using the government's
school league tables to inform school choice. This has promoted public
understanding of the problems of league tables through widespread
communication to non-academics via popular articles and other media,
including interviews for the BBC Radio 4 programmes `Analysis' and `The
Learning Curve' and articles in the Financial Times, Daily Telegraph and
Times Educational Supplement [c]. This work demonstrates impact in terms
of both reach and significance, given that it has been incorporated into
policy documents by numerous governments and non-governmental
organisations, both overseas (including the OECD) and UK (including the
National Union of Teachers and the Institute for Government), to influence
public thinking and new policy development on educational accountability
and improvement issues [d].
Improved understanding of rural educational issues: A further
example of the importance of strong statistical research [4] with
associated software [3] for educational research resulting in societal
benefit is a recent Department for Environment, Food and Rural Affairs
report [e] in which the new sophisticated methods were used to investigate
whether higher attainment of rural school pupils was symptomatic of a
better educational environment or simply a by-product of generally higher
social position in rural areas. Missing data, and multilevel structure,
are endemic in such a study, and [3] was necessary since "the use of
multiple imputation in this study should provide more accurate [analyses]
than a complete case analysis [throwing out records with missing data],
and should also increase the power of the analyses so that small
differences between settlement types can be more easily distinguished"
[e].
B. Admissions to UK universities
The Schwartz Report on Fair Admission (2004) was instigated to review
"options which English institutions providing higher education should
consider in assessing the merit of applicants for their courses."
Consequently, the Supporting Professionalism in Admissions programme was
set up to support higher education institutions to develop admissions
policies ensuring fair access. The programme has recently carried out a
major investigation into the use of so-called contextual data to inform
admissions decisions, publishing a 2012 report [f]. The data supporting
the review was multilevel in nature, and extensive (between 0.4 and 1.6
million individual school records). "With such a sensitive issue, it was
important to fit a statistical model that would be robust to criticism"
[g]. A recent version of MLwiN, which incorporates the latest MCMC module
[1] incorporating the advanced MCMC techniques developed by [2] "was
necessary to achieve satisfactory results with such a high volume of data
and highly correlated variables of interest" (type of school and
educational attainment being two key candidate explanatory variables for
degree performance) [g]. The report concludes that the type of school is
an important predictor of degree performance. The recommendation to HEIs
is therefore to incorporate such contextual information in their
admissions decisions, thus having an impact across the UK in terms of
accessibility of higher education.
C. Equality and diversity policy for REF2014 submissions
Analysis of RAE2008 data was carried out by the Higher Education Funding
Council for England using MLwiN. One aspect of this was a multilevel
analysis over 30,000 records with a binary response to indicate whether an
individual was included in the RAE2008 submission. "To carry out such a
large multilevel analysis with binary response data required the use of
the recent optimised MCMC components of MLwiN" [1], based on the research
of [2] [g]. A key finding was of selection biases against certain ethnic
groups that were not explained by controlling for other factors [h]. In
response, significantly improved rules on equality and diversity have been
introduced for REF2014 (http://www.ref.ac.uk/equality/),
thus having a significant impact on UK Higher Education.
Sources to corroborate the impact
[a] Director General, Monitoring and Assessment, UK Statistics Authority
has provided information about influence of University of Bristol research
on government and public understanding of UK policy on school evaluation.
[b] Consultant Statistician to DfE.
May be contacted to corroborate the influences of Centre for Multilevel
Modelling team's value-added studies on and use of MLwiN by DfE
statisticians and Ofsted.
[c] Sources to corroborate engagement with public.
http://news.bbc.co.uk/1/shared/spl/hi/programmes/analysis/transcripts/30_01_12.pdf
http://www.bbc.co.uk/radio4/factual/learningcurve_20080616.shtml
http://www.ft.com/cms/s/0/17dfb862-7ad4-11de-8c34-00144feabdc0.html
http://www.telegraph.co.uk/education/secondaryeducation/6005906/Grammar-schools-penalised-by-new-league-tables.html
http://www.tes.co.uk/article.aspx?storycode=6009334
[d] Wildeman (2011) "Beware of the misleading means and measures". In Transformation
Audit 2011, published by The Inclusive Economies Project, which is
located within the Policy and Analysis Unit of the Institute for Justice
and Reconciliation (IJR). http://transformationaudit.org/
blog/wp-content/uploads/2012/02/Opinion-Beware-of-the-misleading-means-and-measures.pdf
Mulgan (2010) "Transparency Occasional Paper 1: Transparency and Public
Sector Performance". Queensland Office of the Information Commissioner and
the Australia and New Zealand School of Government working paper, http://www.anzsog.edu.au/media/upload/publication/93_1-Mulgan-Transparency-and-Public-Sector-Performance.pdf
Masters, Rowley, Ainley and Khoo (2008) "Reporting and comparing school
performances". Commissioned by the Reporting and Accountability Branch,
National Education Systems Group, Commonwealth Department of Education,
Employment and Workplace Relations (DEEWR) http://apo.org.au/research/reporting-and-comparing-school-performances
OECD (2008) "Measuring improvements in learning outcomes: Best practices
to assess the value-added of schools." Organisation for Economic
Co-operation and Development, DOI:10.1787/9789264050259-en
Rosenkvist, M.A. (2010) "Using student test results for accountability
and improvement." OECD Education Working Paper 54,
DOI:10.1787/5km4htwzbv30-en
[e] "Educational Attainment in Rural Areas" A report prepared for the
Department for Environment, Food and Rural Affairs by the National Centre
for Social Research (NatCen), 31 December 2009. http://www.natcen.ac.uk/media/665690/c5974000-7879-4f01-890f-c31cf9ca7489.pdf
[f] "Fair Admissions to Higher Education: Research to describe the use of
contextual data in admissions at a sample of universities and colleges in
the UK." Research report by Kath Bridger, Jenny Shaw (BSV Associates Ltd)
and Joanne Moore (ARC Network) for the Supporting Professionalism in
Admissions (SPA) Programme. http://www.spa.ac.uk/documents/ContextualData/Full_SPA_Contextual_data_Research_Report-Feb2012.pdf
[g] Head of Quantitative Analysis for Policy, HEFCE. May be contacted to
corroborate that the most recent versions of MLwiN were needed to carry
out the analyses.
[h] "Selection of Staff for inclusion in RAE2008," http://www.hefce.ac.uk/media/hefce1/pubs/hefce/2009/0934/09_34.pdf