Title: Merging%20Local%20Research%20Data%20with%20PLASC:%20An%20application%20on%20the%20Appropriateness%20of%20Free%20School%20Meals%20as%20a%20Measure%20of%20Deprivation%20in%20Educational%20Research%20in%20Hampshire.
1Merging Local Research Data with PLASCAn
application on the Appropriateness of Free School
Meals as a Measure of Deprivation in Educational
Research in Hampshire.
- Daphne Kounali and Tony Robinson
- Department of Mathematical Sciences
- University of Bath
2The HARPS study
- The HARPS project is an acronym for
- Hampshire Research with Primary Schools
- Objective Assess the impact of school
composition upon student academic progress. The
main aim of the study is to estimate and better
understand compositional effects at the primary
school level. - Definitions Compositional effects are a subset
of contextual effects. Compositional effects
attempt to operationalise the influences of
fellow pupils characteristics on individual
pupils performance. - Compositional variables included in this study
will be social economic status (SES), ethnicity,
gender, prior achievement, special educational
needs (SEN) and age. - A further remit of the study is to evaluate the
probity of FSM as a proxy for the economic
element of SES.
3Study Design
- The research design is both quantitative and
qualitative. Like a set of Russian dolls the
project design is of 3 nested parts - A large scale analysis of over 300 primary
schools - A study of a subsample of 46 schools in the
Basingstoke and Dean area. - More detailed case studies of 12 schools.
4The Basingstoke sub-sample
- One purpose of the Basingstoke subsample is to
test the sensitivity of the quantitative measures
and methodologies, including FSM, used to
identify compositional effects. - To this end we have collected and are analysing
detailed family background information from the
year 3 children in the 46 Basingstoke schools.
These schools have been selected so as to compare
the findings from these schools with those of the
overall Hampshire cohort. - This will not only test the probity of measures
such as FSM for the Hampshire dataset but will
also throw light on their use for school
effectiveness studies in general.
5- The Basingstoke subsample dataset contains family
background data on 1653 pupils from a total of
2012 students attending 46 out of all 50 schools
in the Basingstoke and Dean area. Relevant to
economic status these data include - Occupational group, Working status, Home
ownership, Whether in receipt of Working Tax
Credit, Whether in receipt of FSM. - Other information was collected on ethnic
background, family structure, out-of-school
childcare arrangements and cultural behaviour.
These data were collected at the beginning of
2004 for year 3 pupils (7 year old) from these
schools.
6- One other measure that is becoming popular in
research is the Index of Multiple Deprivation - (IMD)(Noble et al., 2004)
- However this relates not directly to individuals
but to the small geographical area in which they
live, known as a low level Super Output Area
(SOA) containing on average about 1500 people.
IMD is a composite index based on indices grouped
within seven domains - Income Employment Health deprivation and
disability - Education, skills and training Barriers to
housing and services Living environment Crime
7The Deprivation Geography of Hampshire based on
the Multiple Deprivation Index
Our Basingstoke Schools on the Deprivation Map
The schools are represented by their DFES codes
8- As a competitor to FSM, the IMD or its income
component could be used as a distant proxy for
economic deprivation but technical problems arise
when it is desired to assign a deprivation index
to an individual who may or may not share the
fortunes of an average neighbour. - In general it is not too difficult to assign a
deprivation index to a school using IMD
information from the SOAs from which the school
draws its pupils. This is then an alternative to
using the percentage of pupils eligible for FSM
as an indicator of economic deprivation at the
school level. Note that the education component
of the IMD contains achievement data on
performance at Key Stages 2, 3 and 4 which may
well preclude it as independent information used
as input to an analysis of such performance.
9FSM and how it is used
- FSM is frequently used as a factor in
representing economic disadvantage in educational
research - (studies of attainment or truancy)
- LEAs incorporate FSM figures in calculating SEN
and AEN provision - Only statutory available information on economic
disadvantage - Used as a proxy indicator of economic
disadvantage and more generally low SES
10Current FSM eligibility
- The current eligibility criteria are that parents
do not have to pay for school lunches if they
receive any of the following - Income Support
- Income-based Jobseeker's Allowance
- Support under Part VI of the Immigration and
Asylum Act 1999 - Child Tax Credit, provided they are not entitled
to Working Tax Credit and have an annual income
(as assessed by HM Revenue Customs) that does
not exceed 14,155 - the Guarantee element of State Pension Credit.
- Children who receive Income Support or
income-based Job Seeker's Allowance in their own
right qualify as well.
11What is FSM
- FSM eligibility is a measure of extreme
socio-economic disadvantage - At pupil level indicates the pupils family
economic disadvantage - At school level its aggregate indicates
proportion of families suffering extreme economic
disadvantage - It is not a direct indicator of non-economic SES
disadvantage
12Criticisms
- The popularity of such uses of FSM eligibility in
studies in educational research is based on its
availability. There is no other measure of
socio-economic disadvantage that is universally
or even widely available at individual pupil
level. - Registration is voluntary affected by shame,
social class differentials? - Schools encourage registration because it affects
school income - Do families consistently qualify over time?
- Often used as a broad indicator of SES but for
example does not directly indicate cultural
capital
13The use of Large-Scale Data-Bases on Educational
Data
- Opportunities for advantages of using large
pre-existing data sets - Conceptual and logistic problems in working with
these data sets - Statistical Issues germane to the analysis of
large, complex data bases
14The pros
- A means for identifying or enumerating cases
they can provide the sampling frame can be
especially helpful in identifying rare events
i.e. our subsample statistics indicate that 7.5
incidence of FSM eligibility in the Basingstoke
and Dean area compared with a yearly estimate of
9 between 2002-2005. - Provide a broad, if imprecise overview Frequent
existing large data bases can be utilized to
measure and define the magnitude and distribution
of a problem to more definitive study requiring
primary data collection. - This is particularly important in studies in
social sciences and education where the phenomena
under study are not themselves directly
measurable and must be studied indirectly through
the measurements of other observable phenomena. - This is true for both the outcomes we are
measuring - i.e. we want student progress and we measure test
performance - as well as the predictors used
- i.e. we want socioeconomic disadvantage and we
measure a number of indicators for this including
FSM. -
15- Could provide directions of the size of
measurement error in our predictors as well as
the direction of bias induced by non-response.
Our Basingstoke subsample was found to have
higher intakes (baseline tests) in literacy,
lower incidence of SEN and FSM compared with the
rest of Hampshire. - Provide opportunities to Validate the quality of
research data in terms of what these indicators
actually measure as well as address missingness.
In our sample for example non-responders were
found to be twice more likely to be FSM eligible
(using the PLASC information)
16Conceptual and structural pitfalls
- They can be frequently flawed. There are 2
reasons for this and both related to the fact
that those who design and compile data bases
cannot consider the particular needs of every
person who eventually might use them. - First, PLASC is primarily used for administrative
functions related to LEA funding and related
policies not always explicitly stated and could
be changing. It is simply not designed or
maintained to maximize data quality or
consistency. Codes and records layouts (i.e. SEN)
may be changed periodically. - Data elements (i.e. UPNs from the earlier years
might be unreliable pupil identifiers and the
same applies for school identifiers after school
mergings or closings) are often incomplete and
unreliably coded. Information might be
inconsistently recorded across LEAs (i.e.
literacy tests at reception)
17Pitfalls continue
- Second, even in well-maintained data bases
(Hampshire LEA with a long history of research
collaborations) the original goals that dictated
what data were collected will not coincide with
those of subsequent users and coding practices
(i.e. SEN assessed externally) might make
secondary analysis difficult if not impossible.
Inclusion of both persons and services might be
linked to program policies that might change over
time. Another example is associated with the
LEAs communication with the individual school
systems and heterogeneity among schools in the
type of the actual tests administered (e.g. QCA).
In most cases we do not know - How were the data collected and processed
- The time-frame of data collection
- Completeness and coherence among databases of
different LEAs
18Another example of complex problems in usage
- Our original population cohort consists of 11793
(51 boys) of all Hampshire pupils who took the
baseline test during 2001-2002 and their KS1
tests during 2003-2004. We have test results for
approximately 84 of this cohort. The
Hampshire-wide size of the cohort of Reception
pupils from PLASC 2001/02 is 14329 and the size
of the Yr2 pupils from PLASC 2003/04 is 14308. - The pattern of longitudinal losses in terms of
test-results seems quite typical for Hampshire
for this phase, judging for other historical
cohort data that we also had access to. A wave of
around 2000 pupils are lost as we move in time
because they are leaving Hampshire schools and
another wave of 2000 new pupils are coming-into
to these schools. - Because of data-inconsistencies related to
correctly identifying and recording school
changes (school merging or closing) we end-up
looking at 11702 pupils for the phase Baseline to
KS1 data. These pupils come from 318 (Infant or
Junior and Primary Schools) at baseline and
302 schools at KS1.
19Back to FSM in HARPS and the pros
- Some subsample statistics
- Out of the 1653 Basingstoke families 124 were
receiving FSM (7.5) - Of these 13 claimed to receive working tax-credit
- Single parents and non-working couples account
for the majority of FSM recipients - So FSM is a very coarse indicator, can we do
better? - What about the economically deprived that do not
fall below the FSM economic threshold? - No indication of how much the better off
actually are?
20A scale of economic status
We estimate a latent score for the unobserved
economic status using relevant data
and Use this Instead of FSM as input to
modelling
X1
Y1
X2
Y2
Latent Index ?
Y3
X3
X1 Working status X2 SES (assessed by
occupation records) X3 education level of the
parent
Y1 Tax-Credit Y2 FSM eligibility Y3 Home
Renting
A graphical representation of the MIMIC model
(Multiple-Indicator-Multiple-Cause)
21FSM stability
- There is a widely held view that FSM eligibility
status is stable over time as the following quote
shows -
22FSM stability in Hampshire 2002-05
23Who of these ever received FSM?
24(No Transcript)
25Observations on FSM stability
26Assessing the effect of deprivation on school
performance
So, FSM does NOT work
27More Consequences of the choice of deprivation
indexRanking school Under-Performance
- School Ranks for the Lowest threshold of the KS1
testing scale - Comparison of school rankings based on FSM and
our index suggest that schools can be judged
performing worse when FSM is used instead of the
deprivation index. - So, when we use FSM we tend to under-estimate
school performance. - This is because FSM eligibility under-estimates
the prevalence of economic deprivation. - Moreover, we also under-estimate the uncertainty
associated with these rankings.
The differences in rankings affect mostly Average
(typical) performing schools
The plots depict the school-level residuals
(probit scale) against their rank-order. Large
negative values in the probit scale characterize
the best performing schools.
28The area where FSM under-estimates school
performance is below the diagonal line.Higher
Residual Ranks indicate Worse Performance
- 61 - 71 (depending on the residuals considered
for each threshold of the KS1 scale) - of the schools are judged as performing worse
when using FSM rather than using our index. - Moreover, the bias also seem to be differential
- More deprived schools (in terms of intake and/or
FSM eligibility) being affected more.
29Derivation of the index of disadvantage
- A MIMIC model (Multiple-Indicator-Multiple-Cause)
model was used for the derivation of a scale
representing economic disadvantage. Binary data
on three indicators of economic disadvantage - Y1 working tax-credit, Y2 FSM eligibility, Y3
Home renting) are used - in a two-parameter logistic model (Rasch-model)
as follows - logitPr(yij??j) dij?i dij ?i?j, for indicator
i1,2,3 and subject j - where di is a three-dimensional vector
- for the i-th element equal to 1 and all other
elements equal to zero - and ? is the latent unobserved measure of
economic disadvantage. - The parameter estimates for ?i (location
parameters, or intercepts) represent the potency
of each indicator. - The parameters ?i (factor loadings) represent the
discriminating ability of each indicator.
30- We also specified a structural model for the
latent economic disadvantage, allowing the mean
indicator potencies to differ between groups as
follows - ?j?0?1X1?2X2?3X3?di1X1,
- where X1 working status, X2 SES assessed from
occupation records, X3 level of education - The term ?di1X1 allows us to introduce a direct
effect of working tax credit on the receipt of
working tax credit, apart from its indirect
effect through the latent variable. - This is needed since only employed people would
be - in receipt of tax-credit.
31- The intercepts estimates suggest that the
estimated indicator potencies increase from FSM
to renting with FSM being the most difficult
benefit to get. FSM eligibility does have the
highest discriminating ability (slope) as
expected followed by home renting. - As expected the estimated parameter ? indicates
that the odds of receipt of of working tax-credit
are significantly reduced for non-working couples
compared with the typical couple where one is
working full-time and the other part-time.
32- Higher SES reduces economic disadvantage compared
to middle classes - Low or unknown SES increases economic
disadvantage. - Higher education level is associated with reduced
economic disadvantage. - Non-working couple are significantly more likely
to be economically disadvantaged, as expected,
compared with the typical working status of a
couple in this sample (one working full-time and
one part time) with the single part-time parents
following closely. - Couples consisting of partners where only one
full-time working time are also significantly
more disadvantaged compared to the typical
working couple which appears similar to couples
where both partners work full-time. - It is interesting to note that couples consisting
of partners where one is working full-time and
the other is self-employed, are significantly
less disadvantaged compared with the typical
couple
33- Working tax-credit is a much
- More useful indicator especially
- For middle class occupations
- FSM refers to
- very disadvantaged children
- even among low SES families
34- Receipt of Working tax credit
- as an indicator of economic disadvantage seem to
INDEX - occupation based SES, MOSTLY but not always.
- This might be due to bias associated with
- reporting occupation and/or
- assumptions on occupation rankings.
- Receipt of Working tax credit
- as an indicator of economic disadvantage seem to
INDEX - level of parental education less well.
- It seems that level of education is consistent
with economic disadvantage for the very poor. - The economic value of vocational qualifications
seem less clear for more typical incomes. - This could also be due to the fact that in our
sample - 90 of the responders are women and only 60 of
these women contribute to the determination of
SES.
35Further developments
- Improvements in the construction of the index
- Allow for differential measurement error through
joint modelling instead of plugging-in index
estimates. - In the structural part of the model include
interaction terms for education level and the
identity of the major bread-winner.
- Address problems related to endogeneity i.e.
economic disadvantage - might affect both school intakes as well as KS1
test results, - and there might be both direct and indirect
effects - of economic disadvantage on school performance.
36Conclusions
37- As far as the use of PLASC data is concerned the
conclusion is - Documentation and Documentation and
- The importance for the research community to get
involved with the development and progress of
maintaining and improving such invaluable data
resources as the PLASC data.