IFS
When you are born matters:
the impact of date of birth on child
cognitive outcomes in England
Claire Crawford, Lorraine Dearden & Costas Meghir
Institute for Fiscal Studies
The English education system
• By law, children must have started school by
the beginning of the term after they turn five
• Local Education Authorities (LEAs) are free to
set admissions policies within this framework
• The academic year runs from 1st September
to 31st August
– We would expect August-born children to perform
worse than September-born children
© Institute for Fiscal Studies, 2007
Raw differences (example)
.9
.8
.7
.6
.5
.4
.3
.3
.4
.5
.6
.7
.8
.9
KS3 - Proportion at expected level
1
Mean of Outcome
1
Mean of Outcome
Nov85 Feb86 May86 Aug86 Nov86 Feb87 May87 Aug87 Nov87 Feb88 May88 Aug88
Nov85 Feb86 May86 Aug86 Nov86 Feb87 May87 Aug87 Nov87 Feb88 May88 Aug88
Mean of Outcome
Mean of Outcome
.9
.8
.7
.6
.5
.4
.3
.3
.4
.5
.6
.7
.8
.9
KS5 - Proportion at expected level
1
Day of Birth
1
Day of Birth
Nov85 Feb86 May86 Aug86 Nov86 Feb87 May87 Aug87 Nov87 Feb88 May88 Aug88
Nov85 Feb86 May86 Aug86 Nov86 Feb87 May87 Aug87 Nov87 Feb88 May88 Aug88
Day of Birth
Day of Birth
Males
© Institute for Fiscal Studies, 2007
Females
Data
• Administrative data on all children attending
state school in England
– Test results from age 5 to age 18
• Not possible to follow the same individuals all
the way through, so consider three groups:
– Group 1 (test results at ages 5 and 7)
– Group 2 (test results at ages 7, 11 and 14)
– Group 3 (test results at ages 11, 14, 16 and 18)
© Institute for Fiscal Studies, 2007
Modelling strategy
• In general, we compare children born in
August with children born in September
– In the same school (and school year)
– With the same observable characteristics
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Research questions
1. What is the extent of the August birth penalty, and
how does this vary by age?
2. What is the best admissions policy for summer-born
children (in terms of cognitive outcomes)?
3. What drives differences in cognitive outcomes
between August- and September-born children?
4. Does the August birth penalty vary across particular
subgroups of interest?
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What is the extent of the August birth
penalty, and how does it vary by age?
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Comparison of percentages of August- and
September-born children reaching expected level
Group 1
Key Stage 1
Key Stage 2
Key Stage 3
Key Stage 4
Key Stage 5
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Group 2
Girls
Boys
Girls
Boys
Sep
80.1
70.5
70.3
61.2
Aug
53.0
47.1
44.6
34.9
Sep
76.0
Aug
Group 3
Girls
Boys
71.9
65.4
60.9
62.7
59.1
50.0
45.9
Sep
72.9
68.8
65.9
61.6
Aug
65.2
60.3
57.1
51.9
Sep
60.7
50.3
Aug
55.2
44.2
Sep
42.5
33.2
Aug
40.5
31.5
Percentage point difference between August- and
September-born children reaching expected level
Group 1
Key Stage 1
Key Stage 2
Key Stage 3
Key Stage 4
Key Stage 5
© Institute for Fiscal Studies, 2007
Group 2
Girls
Boys
Girls
Boys
-27.1
-23.4
-25.7
-26.3
-13.3
-7.7
Group 3
Girls
Boys
-12.8
-15.4
-15.0
-8.5
-8.8
-9.7
-5.5
-6.1
-2.0
-1.7
Comparison of percentages of August- and
September-born children diagnosed with special
educational needs
Group 1
(age 5)
Statemented
Non-statemented
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Group 2
(age 11)
Group 3
(age 16)
Girls
Boys
Girls
Boys
Girls
Boys
Sep
0.6
1.6
1.6
4.2
1.7
4.0
Aug
0.5
1.3
2.0
4.8
2.1
4.8
Sep
3.3
7.5
11.3
20.5
8.5
14.1
Aug
5.3
9.4
19.4
29.9
10.5
17.6
Percentage point difference between August- and
September-born children diagnosed with special
educational needs
Group 1
(age 5)
Statemented
Non-statemented
© Institute for Fiscal Studies, 2007
Group 2
(age 11)
Group 3
(age 16)
Girls
Boys
Girls
Boys
Girls
Boys
-0.1
-0.3
0.4
0.6
0.4
0.8
2.0
1.9
8.1
9.4
2.0
3.5
Does the August birth penalty vary
by subgroup?
• We made comparisons across several
groups, e.g.
– FSM vs. non-FSM
– Black Caribbean vs. White British
• Most noteworthy finding is the lack of
significant differences across subgroup
– August birth penalty is the same for all individuals
© Institute for Fiscal Studies, 2007
Hypotheses
• Why might August-born children perform
more poorly than September-born children?
–
–
–
–
Age of sitting the test (absolute age) effect
Age of starting school effect
Length of schooling effect
Age position (relative age) effect
© Institute for Fiscal Studies, 2007
How can we find out what drives the
August birth penalty?
• Variation in admissions policies is important
• Children born on the same day (who start
school in different areas) may:
– Start school at different ages
– Receive a different number of terms of schooling
• Also separates age of starting school from
date of birth (the absolute age effect)
© Institute for Fiscal Studies, 2007
Modelling strategy
• Modelling strategy now involves comparing
children born on the same day across
admissions policy areas
– Controlling for observables is very important
© Institute for Fiscal Studies, 2007
What drives the August birth
penalty?
• Outcomes of August-born children are:
– Considerably worsened because they are younger
when they sit the test
– Slightly worsened because they are amongst the
youngest in their year
– Slightly improved in areas where they start school
earlier (have more terms of schooling)
• Greater for girls than for boys
• Does not persist beyond Key Stage 3 (age 14)
© Institute for Fiscal Studies, 2007
What is the best admissions policy
for summer-born children?
• It is best for August-born children to start
school at the same time as September-born
children
• But effects are small and do not persist
– Changes to admissions policies will not come
close to eliminating the August birth penalty
© Institute for Fiscal Studies, 2007
Possible Policy Responses...
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The Policy Dilemma
• Results we have shown emphasise August
birth penalty, but results much more general
than this
– on average, the younger you are in the school
year, the worse you do
• Policy options ideally need to create a level
playing field for all children, regardless of
their date of birth
• But also need to have school years, and
somebody is always going to be the
youngest, regardless of the policy
© Institute for Fiscal Studies, 2007
What are the policy options?
• Flexibility in age of starting school
• Holding children back
• Age adjustment of tests/testing when ready
• Other options and considerations
© Institute for Fiscal Studies, 2007
Flexibility in school starting age
• English system unique in that most children
stay in allocated school year – is this
inflexibility part of the problem?
• Not obvious to us that it is – some US
evidence that flexibility creates more severe
summer born penalties
• Need to ensure that flexibility is used
appropriately
– What criteria do you use?
– Make sure decisions not determined by economic
circumstances
– Or school choice issues
© Institute for Fiscal Studies, 2007
Holding children back?
• Conservatives have mooted holding children
back in Year 6 if haven’t reached expected
levels
• But clear from data that with the current
system much more likely that August born
children would be held back unnecessarily
compared to September born children (if KS2
results used)
– See Tables 9.2 and 9.3 of report
© Institute for Fiscal Studies, 2007
Age adjustment and/or testing
when ready
• Could just adjust test scores to take account
of age
– Use principle that proportion getting expected
level should not vary by month of birth
– Simple linear adjustment (show this works in
report)
– For externally marked exams such adjustment
should be relatively straight forward
– For internally marked exams probably needs to be
based on previous cohorts
© Institute for Fiscal Studies, 2007
Another way?
• Rather than setting expected level for a whole
school year set it for a particular age
– E.g. Expect person to reach level 2B at age 7 ½,
level 3 by 9 ½, level 4 by 11 ½ , level 5 by 13 ½...
– Creates level playing field
• This is implicit age normalisation
– But for this to work, need to have more flexibility in
when children are tested e.g. testing when ready
– Works best if testing can happen when truly ready
(i.e. the more testing slots during the year the
better)
© Institute for Fiscal Studies, 2007
But some problems?
• How do you measure school performance?
• Clear to us should be based on age adjusted
scores/expected levels
– We can show that age adjusting scores
dramatically changes school rankings within LEAS
for Key Stage 2 (70% of schools change rankings)
and Key Stage 3 results (20% of schools change
rankings)
– Some of these movements are very large
© Institute for Fiscal Studies, 2007
Transitions at 16
• Clear to us that it is an urgent policy priority to
ensure transitions at age 16 are based on
age adjusted attainment
– Schools/FE colleges often have grade criteria for
continuing certain subjects/courses of study
– This must be based on age adjusted criteria or
summer born students in particular will be
disadvantaged
• If children leave school, then they take away
their actual qualification (need actual level of
human capital for labour market)
© Institute for Fiscal Studies, 2007
Other options?
• Teachers and parents need to be made more
aware of the impact of date of birth penalties
• LEAs should consider allowing all children to
start school in September
• Reconsideration of rules for free nursery
provision
– Make free provision available in the year in which
child turns 3 rather than in term after they turn 3
– Current system means summer born children
generally entitled to less free provision
© Institute for Fiscal Studies, 2007
Panel Discussion
© Institute for Fiscal Studies, 2007