Dean R. Lillard1,3, Richard V. Burkhauser2,3,4, Markus H. Hahn4 and Roger Wilkins4
1Ohio State University, 2Cornell University, 3DIW-Berlin, 4Melbourne Institute, University of Melbourne
July 2013
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Does Early-Life Income Inequality Predict Later-Life Self-Reported Health?
Evidence from Three Countries
Hypothesised effects(Leigh, Jencks and Smeeding, 2009)
• Absolute income hypothesis (health concave in income)
• Relative income (or relative deprivation) hypothesis (“status anxiety” – chronic stress from relative deprivation)
• Violent crime (including second-order effects on stress)
• Public spending (not necessarily only health-related)
• Social capital and trust (“income inequality hypothesis” of Wilkinson (1996) – various mechanisms, including effects on demands for public spending)
(Matters for both health policy and redistribution policy)
Introduction – What’s the link between inequality and health? (And why does it matter?)
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(+) Infant mortality
(–) Life expectancy
(–) Average age at death
(+) Mortality risk
(–) Self-reported health
Empirical evidence – Earlier studies (mostly 1980s and 1990s)
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• Cross-sectional data
• Health usually measured by aggregate statistic for whole country
• Not always comparable across countries
• Often for single or limited number of years
• Failure to account for substantial heterogeneity (lack of controls)
• Weak theoretical support
• Relates current health to current inequality
Shortcomings of older literature
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• Individual-level data – better controls• Better / Alternative health measures• Better / Alternative inequality measures
More mixed results
These include studies:
• Using panel data on self-reported health (Weich, Lewis, and Jenkins 2002; Lillard and Burkhauser 2005; Lorgelly and Lindley 2008; Bechtel et al. 2012)
• Using alternative measures of inequalityIncluding data from tax records (Leigh and Jencks 2007)
• Examining lagged effects (Blakely et al.,2000; Mellor and Milyo, 2003; Karlsson et al. 2010)
More recent studies
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Combine:1. Panel data on self-rated health from three
countriesAustralia, Great Britain, United States
2. New long-run country-level inequality measure
from administrative tax records
Investigate whether there is a link between early-life inequality (average in first 20 years of life) and later-life self-reported health
What is the potential mechanism?Public spending / immunisation etc. most important when young – that is, health investments when young an important determinant of health in adulthood.
Our contribution
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• US Panel Study of Income Dynamics (PSID)• British Household Panel Study (BHPS)• Household, Income and Labour Dynamics in
Australia Survey (HILDA)
Sample selectionPSID: 1984 to 2009
BHPS: 1991 to 2008
HILDA: 2001 to 2011
Native-born individuals aged 21 and older
Born after tax data first observed
Britain: 1908 US: 1913Australia : 1921
Data (other than for early-life inequality)
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5-point scale in all countries:PSID: Would you say your health in general is excellent, very good, good, fair or poor?
BHPS: Please think back over the last 12 months about how your health has been. Compared to people of your own age, would you say that your health has on the whole been excellent, good, fair, poor or very poor?
HILDA: In general, would you say your health is excellent, very good, good, fair or poor?
Limitations:• Not entirely certain what is being measured,
especially by HILDA and PSID (time frame, reference point)
• Potential endogeneity (eg, Johnston et al., 2009)
Health measure
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Health measure distribution (%)Males
US GB AU
Excellent (Excellent) 25.5 26.7 10.3
Very good (Good) 33.0 45.1 35.1
Good (Fair) 26.7 19.8 36.9
Fair (Poor) 10.6 6.6 14.4
Poor (Very poor) 4.2 1.8 3.3
FemalesUS GB AU
Excellent (Excellent) 19.7 22.7 10.5
Very good (Good) 31.5 44.9 36.3
Good (Fair) 31.1 21.6 35.6
Fair (Poor) 13.0 8.5 14.5Poor (Very poor) 4.8 2.4 3.2(GB categories in parentheses)
Tax records Income share of the top 1%Available from early 20th century to present day
• Data for AU from Burkhauser, Hahn and Wilkins (2013)• Data for GB and US from Top Incomes Database on the
Paris School of Economics web site• Excludes capital gains in AU and US; some of GB series
includes some capital gains
Inequality variable: Average income share of the top 1% over the first 20 years of life
Each birth cohort has the same value. Identification comes from temporal variation. Age can be controlled for because we have multiple years of data on self-reported health
Inequality data
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• Pre-tax income
• Sensitive to the personal income tax base
• Tax unit differs across countries and time:
Australia – individualGB – family until 1989, individual afterUS – family
• Top income share is correlated with measures of overall income inequality such as the Gini coefficient, but it’s not the same thing (Leigh, 2007)
Inequality data – Limitations
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1908
1911
1914
1917
1920
1923
1926
1929
1932
1935
1938
1941
1944
1947
1950
1953
1956
1959
1962
1965
1968
1971
1974
1977
1980
1983
1986
1989
0
5
10
15
20
25
Average income share of the top 1% in the first 20 years of life, by birth year
UKUSAAustralia
Birth year
%
Estimate ordered probit modelsStart with parsimonious model and progressively add controls
M1: Early life inequality and time/period controls onlyM2: M1 + age controlsM3: M2 + permanent household incomeM4: M3 + Father’s education and occupation
Permanent income: Log of average equivalised income over all years up until two years before health measured
Also control for the number of years over which permanent income measured
Father’s education and occupation: Proxies for early-life economic resources
Cluster on birth year
Empirical strategy
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Results (coefficient estimates) – Men
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M1 M2 M3 M4 Sample size
US
Early-life inequality-
0.1196***
-0.0394**
*
-0.0329**
*- 101,743
Britain
Early-life inequality-
0.0553***
-0.0171** -0.0072 -0.0064 78,419
Australia
Early-life inequality-
0.1393***
0.0190 0.0483*** 0.0440** 38,036
Time controls Yes Yes Yes Yes
Age controls No Yes Yes Yes
Permanent income No No Yes Yes
Early-life income No No No Yes
Results (coefficient estimates) – Women
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M1 M2 M3 M4 Sample size
US
Early-life inequality-
0.1162***
-0.0456**
*
-0.0280**
*- 124,806
Britain
Early-life inequality-
0.0526***
-0.0121** 0.0015 0.0018 91,184
Australia
Early-life inequality-
0.1483***
0.0055 0.0108 0.0087 43,941
Time controls Yes Yes Yes Yes
Age controls No Yes Yes Yes
Permanent income No No Yes Yes
Early-life income No No No Yes
Mean marginal effects of early-life inequality – US (Model 3)
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Men Women
Excellent -0.0096*** -0.0070***
Very good -0.0019*** -0.0029***
Good 0.0048*** 0.0036***
Fair 0.0042*** 0.0040***
Poor 0.0024*** 0.0023***
• Restrict to the 2001-2009 period for all countries
• Restrict to the 1991-2009 period for US and GB
• Alternative specifications of time effects
• Alternative specifications of age effects
Yet to examine whether US result robust to inclusion of measures of early-life income.
Robustness checks and caveats
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Focus on current inequality and current health theoretically weakWe find evidence that early-life inequality matters in the USPermanent income and early-life income also appear to matter
Further work:• Early-life income measure for US• Consider differences in effects of early-life
income inequality by level of early-life income
• Consider inequality at other ages• Explore other (objective?) measures of
health (but data limitations)
Discussion
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