Parental Income and Children’s Smoking Behaviour: Evidence from the British Household Panel Survey
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Transcript of Parental Income and Children’s Smoking Behaviour: Evidence from the British Household Panel Survey
IFS
Parental Income and Children’s Smoking Behaviour: Evidence from the British
Household Panel Survey
Andrew Leicester
Laura Blow
Frank Windmeijer
© Institute for Fiscal Studies, 2005
Child Smoking – targets
• Government target:
Reduce proportion of children aged 11 – 15 who smoke regularly from 13% (1996) to 11% by 2005 and 9% by 2010
» “Smoking Kills – A White Paper on Tobacco” (1998)
© Institute for Fiscal Studies, 2005
Child Smoking - progress
0
2
4
6
8
10
12
14
16
1982 1986 1990 1994 1998 2002 2006 2010
Per
cen
tag
e sm
oki
ng
Boys
Girls
Overall
2005 target
2010 target
Source: Smoking, Drinking and Drug Use among Young People in England in 2004" (Department of Health)
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Current evidence
• Tyas and Pederson (1998)– Literature review of determinants of youth smoking– Consider parental socioeconomic status and
children’s personal income:
• “Higher levels of parental socioeconomic variables, such as education and social class, have often been found to be inversely related to smoking status in adolescents …”
• “… young people with more spending money showed higher levels of smoking …”
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Further studies
• Soteriades and DiFranza (2003)– Study of Massachusetts teenagers– Controlling for children’s demographics and
parental smoking, find:• “The risk of adolescent smoking increased by 28% with
each step down in parental education, and by 30% for each step down in parental household income”
• Conrad et al (1992)– Around ¼ of studies did not support an inverse
relationship between parental SES and childrens’ smoking
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Measuring effect of income• How might parental income affect children’s
smoking behaviour?– Higher incomes allow parents to “buy”
circumstances conducive to lower smoking rates• School, peer, neighbourhood effects?
– But also allow greater consumption of all goods, including cigarettes
• Clear that relationship between parental income and youth smoking may be indirect
• Concern that we may not be able to fully observe these indirect channels
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Innovations of our approach
• Exploit relatively under-used data from the British Youth Panel (BYP) and British Household Panel Survey (BHPS)
• A more direct assessment of the extent to which parental incomes are associated with youth smoking– Use sibling differences to assess possible causal
effect of income on smoking– Strips out unobservable household effects that
determine smoking and are correlated with income
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Data
• British Household Panel Survey (BHPS) / British Youth Panel (BYP)– 1994 to 2001 (waves 4 to 11)– BYP separate data for children aged 11 – 15 in
BHPS– Data from BYP on children’s smoking and
characteristics– Data from BHPS on family backgrounds, SES,
income, smoking status of adults– Track children from BYP into BHPS up to age 18
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Sample Sizes
Number of observations
Number of children
Entire sample 7,288 2,467
Sibling sample 1,951 751
• Sibling sample cases where we observe two or more siblings reaching the same age at different points in time
• Used in sibling difference analysis later
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Smoking behaviour in the BYP
• Child a smoker if:– Responds with positive figure to question “how
many cigarettes did you smoke in the last seven days?” or
– Self-defines as someone who smokes but not every week
• BHPS question is direct yes/no
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BYP evidence on youth smoking: over time
02468
101214161820
Per
cen
tag
e o
f sm
oke
rs
1994 1995 1996 1997 1998 1999 2000 2001
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BYP evidence on youth smoking: by household income decile
0
2
4
6
8
10
12
14
16
18
Per
cen
tag
e o
f sm
oke
rs
1 2 3 4 5 6 7 8 9 10
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Household income and youth smoking: models
• Simple probit for whether child smokes• Models all condition on: year, age, gender,
region, household composition, mother’s age• In addition:
– Condition on household income quintile and then other family background characteristics
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Results
*** = significant at 1% level; ** = significant at 5% level
Baseline smoking probability = 15.6%
Basic Specification Additional controls
Household Income Quintile (Baseline = 4th)
1
2
3
5
Maternal Educational Attainment (Baseline = O Level)
Higher Degree
1st Degree
Vocational
A Level
CSE
None
Adult Smoker?
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Results
*** = significant at 1% level; ** = significant at 5% level
Baseline smoking probability = 15.6%
Basic Specification Additional controls
Household Income Quintile (Baseline = 4th)
1 + 4.2%**
2 + 3.5% **
3 + 0.5%
5 - 0.3%
Maternal Educational Attainment (Baseline = O Level)
Higher Degree –
1st Degree –
Vocational –
A Level –
CSE –
None –
Adult Smoker? –
© Institute for Fiscal Studies, 2005
Results
*** = significant at 1% level; ** = significant at 5% level
Baseline smoking probability = 15.6%
Basic Specification Additional controls
Household Income Quintile (Baseline = 4th)
1 + 4.2%** + 2.0%
2 + 3.5% ** + 1.5%
3 + 0.5% - 0.3%
5 - 0.3% + 1.5%
Maternal Educational Attainment (Baseline = O Level)
Higher Degree – + 4.1%
1st Degree – - 2.6%
Vocational – - 4.1%
A Level – - 0.5%
CSE – + 1.7%
None – + 3.5% **
Adult Smoker? – + 8.5% ***
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Sibling Differences
• Income correlated with observable features of the data, e.g. maternal education
• May also be correlated with unobservable features of the data – peer effects, neighbourhood effects, household preferences, etc.
• Therefore examine relationship between changes in income over time and changes in sibling smoking behaviour
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Sibling Differences• Focus on siblings who reach same age at different
points in time• 1,030 pairs of siblings identified
SmokerNon-
Smoker
Smoker 59 99
Non-Smoker
73 799
Older Sibling
Yo
un
ger
S
ibli
ng
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Model
• Define ∆S = 0 if both siblings smoke/don’t = 1 if only younger smokes = -1 if only older smokes
∆S = f(∆Y, year, age, sex, ∆sex, mother age, age gap between siblings)
NB ∆Y positive if household income rose by the time younger sibling reached same age as older
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Results
OLS IV
Coefficient on ∆Y
Robust Std. Error
Significant?
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Results
OLS IV
Coefficient on ∆Y
0.041
Robust Std. Error
0.024
Significant? 10% level
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Results
OLS IV
Coefficient on ∆Y
0.041 0.134
Robust Std. Error
0.024 0.092
Significant? 10% level No
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Conclusions
• Inverse relationship between household income and youth smoking
• Effect fades once we control for maternal education and presence of adult smoker
• Sibling difference results suggest no direct causal relationship between household income and youth smoking
• If anything, higher incomes increase the likelihood of children smoking slightly