Social determinants of health — how income, education, housing, social support, and neighborhood environment shape health outcomes and drive health inequalities. Built on Berkman & Syme (1979), Marmot (2005), Cutler & Lleras-Muney (2010), Chetty et al. (2016), and Holt-Lunstad et al. (2015).
Constructs
household_income
Household Income
Annual pre-tax income received by all members of a household, inflation-adjusted. Primary measure of material resources for health-relevant consumption.
family incomeincome level
educational_attainment
Educational Attainment
Highest level of formal schooling completed, operationalized as years of schooling or credential level.
years of schoolingeducation level
income_inequality
Income Inequality
Degree of dispersion in income distribution, most commonly measured by the Gini coefficient (0-1 scale).
Gini coefficienteconomic inequality
social_support
Social Support
Share of respondents answering 'yes' to 'If you were in trouble, do you have relatives or friends you can count on?' Gallup World Poll. Ranges 0-1.
social connectionssocial capital (informal)having someone to count onsocial tiessocial connectedness
social_isolation
Social Isolation
Objective lack of social contacts or relationships, measured by network size or frequency of social interaction.
lonelinesssocial disconnection
life_expectancy
Life Expectancy at Birth
Average number of years a newborn is expected to live given current age-specific mortality rates.
longevityall-cause mortality
Findings
Microcredit access has no significant effect on average household consumption, indicating microcredit does not broadly raise living standards in the short to medium term
Direction: null
Confidence: strong
Effect: No statistically significant change in consumption
Method: Cluster-randomized controlled trial across 104 neighborhoods
Expanding microcredit access in the Philippines produces modest positive effects on business profits and scale but does not translate into higher household income
Direction: conditional
Confidence: moderate
Effect: Modest positive on business outcomes; null on income
Method: Randomized credit scoring experiment
Savings products may be more important than credit for the poor, as they provide consumption smoothing and asset building without the risks of over-indebtedness
Direction: conditional
Confidence: moderate
Effect: Qualitative: savings potentially more impactful than credit
Method: Theoretical analysis and program comparison
A consistent social gradient in health runs from top to bottom of the occupational hierarchy; higher social position predicts better health outcomes.
Direction: positive
Confidence: strong
Method: Descriptive epidemiology
Income, insurance, and background account for ~30% of the education-health gradient; knowledge and cognitive ability ~30%; social networks ~10%.
Direction: positive
Confidence: strong
Method: OLS regression
Gap in life expectancy between richest 1% and poorest 1% of Americans is 14.6 years for men and 10.1 years for women.
Direction: positive
Confidence: strong
Method: Descriptive regression, N=1.4 billion
Neighborhood-level characteristics in childhood predict adult income rank with substantial explanatory power (R-squared = 0.5 at census tract level), demonstrating that geography is a powerful determinant of economic mobility.
Direction: positive
Confidence: strong
Effect: R-squared = 0.5 at census tract level
Educational attainment is the strongest individual-level predictor of income, with a correlation of r=0.55 between bachelor's degree attainment rates and median household income across counties.
Direction: positive
Confidence: strong
Effect: r=0.55
The rural-urban income divide continues to widen: metropolitan areas have approximately 2x higher median household income than non-metropolitan areas, with the gap growing over the past two decades.
Direction: positive
Confidence: strong
Effect: 2x metro vs non-metro income ratio
Upward mobility varies dramatically by race and geography: Black boys raised in the same census tract as white boys earn substantially less as adults, suggesting neighborhood effects interact with race to produce divergent outcomes.
Direction: negative
Confidence: strong
Top 1% income share in the United States roughly doubled from approximately 8% in 1970 to approximately 17% by 2000, representing a dramatic U-shaped pattern over the 20th century with high concentration pre-WWII, compression mid-century, and reconcentration since the 1980s.
Direction: positive
Confidence: strong
Effect: Top 1% share: ~8% (1970) to ~17% (2000); top 10% share: ~33% to ~45%
Method: Tax data analysis using IRS individual income tax returns, 1913-1998
Global inequality is driven by two forces moving in opposite directions: between-country inequality is declining (primarily due to China and India's growth) while within-country inequality is rising in most nations, producing complex distributional patterns.
Direction: conditional
Confidence: strong
Effect: Global Gini ~0.70; between-country component declining, within-country component rising
Method: Descriptive analysis of household survey data across countries
The 'elephant curve' of global income growth (1988-2008) shows strong gains for the global middle class (percentiles 30-60, mainly Asian) and the global top 1%, but stagnation for the lower-middle class of rich countries (percentiles 75-90), explaining populist discontent in developed nations.
Direction: conditional
Confidence: moderate
Effect: ~60-70% real income growth for global median vs near-zero for 80th percentile (rich-country lower middle)
Method: Global household survey analysis, income growth by percentile
Inequality follows 'Kuznets waves' — cyclical patterns of rising and falling inequality driven by technological change, globalization, and policy responses, rather than the single inverted-U curve originally proposed by Kuznets.
Direction: conditional
Confidence: moderate
Effect: Cyclical pattern rather than monotonic relationship
Method: Historical comparative analysis
Areas with less residential segregation, less income inequality, better schools, stronger social capital, and more stable families have significantly higher intergenerational mobility. These five factors are the strongest correlates of upward mobility across US commuting zones.
Direction: negative
Confidence: strong
Effect: Segregation, inequality, school quality, social capital, family structure are top 5 correlates
Method: OLS, correlational analysis across 741 commuting zones
Social support is a strong positive predictor of life satisfaction. A one-unit increase in the social support proportion is associated with approximately +1.4 points on the Cantril ladder.
Direction: positive
Confidence: strong
Effect: strong
Method: OLS regression, country-year panel with year fixed effects, N≈1,700 country-years across 2005-2022, Gallup World Poll
People with fewest social ties had age-adjusted relative mortality risks of 2.3 (men) and 2.8 (women) over nine years, independent of SES and health behaviors.
Direction: negative
Confidence: strong
Method: Cox proportional hazards
Meta-analysis of 70 studies: social isolation (OR=1.29), loneliness (OR=1.26), and living alone (OR=1.32) each predicted elevated all-cause mortality.
Direction: negative
Confidence: strong
Method: Meta-analysis, N=3.4 million
Health spending has strong positive effect on life expectancy — each 10% increase in health spending associated with approximately 0.3 year gain in life expectancy at birth.
Direction: positive
Confidence: moderate
Effect: ~0.3 year life expectancy gain per 10% spending increase
Method: Cross-country descriptive and regression analysis
Returns to health spending exhibit strong diminishing returns — high-income countries get less mortality reduction per additional dollar spent.
Direction: conditional
Confidence: moderate
Effect: Diminishing marginal returns at higher income levels
Method: Cross-country comparative analysis
Health spending has strong positive effect on life expectancy — each 10% increase associated with ~0.3 year gain
Direction: positive
Confidence: moderate
Returns to health spending exhibit strong diminishing returns at high income levels
Direction: conditional
Confidence: moderate
Challenge to finding #755: OLS regression on 50 country-year observations (2000-2020) shows health_expenditure_per_capita has a strong positive effect on life_expectancy (β=+0.76 standardized, p<.001, R²=0.58), contradicting the null finding | Reasoning: Filmer & Pritchett controlled for income and education which absorb most of the health spending variation. Without those controls, the raw relationship is strongly positive. The discrepancy reflects an endogeneity debate: richer countries spend more on health AND have better health outcomes, so the causal effect of spending alone is unclear. | Data comparison: different_data | Method comparison: different_method | Method difference: Bivariate OLS without income/education controls vs multivariate with controls
Direction: unknown
Confidence: unknown
Effect: OLS regression on 50 country-year observations (2000-2020) shows health_expenditure_per_capita has a strong positive effect on life_expectancy (β=+0.76 standardized, p<.001, R²=0.58), contradicting the null finding
Method: Bivariate OLS without income/education controls vs multivariate with controls
Mortality decline in the 20th century was driven primarily by public health measures, nutrition, and income growth — not by medical spending.
Direction: null
Confidence: moderate
Method: Historical analysis of mortality trends
Healthy life expectancy positively predicts life satisfaction. Each additional year of healthy life expectancy at birth is associated with approximately +0.03 points on the Cantril ladder.
Direction: positive
Confidence: strong
Effect: moderate
Method: OLS regression, country-year panel with year fixed effects, N≈1,700 country-years across 2005-2022, Gallup World Poll