Table 1
Descriptive statistics of variables.
| Observation | Mean (Range) | |
|---|---|---|
| Life expectancy at birth, total (years) | 1034 | 57.03 (31.96–75.64) |
| Health expenditure per capita, PPP (US$) | 1032 | 202.06 (5.94–1768.68) |
| Out-of-pocket health expenditure (% of total health expenditure) | 1032 | 39.65% (2.00–80.91) |
| Gross domestic product, PPP † (US$) | 1021 | 41.16 (2.72–384.41) |
| Mean years of schooling population 25+ years† | 959 | 4.46 (0.90–10.30) |
| Food production index | 1037 | 100.67 (55.77–182.51) |
| Urban population (% of total) | 1037 | 39.53% (7.21–86.92) |
| CO2 emissions (metric tons per capita)* | 1036 | 112.90 (1.57–1004.37) |
| Improved water source (% of population with access) | 1025 | 68.72% (19.50–99.90) |
| Improved sanitation facilities (% of the population with access) | 1038 | 37.26% (3.00–98.40) |
| Total alcohol consumption, per capita*‡ | 934 | 305.50 (1.00–1189.00) |
[i] † – Divided by 100; * – Multiplied by 100.
‡ Total alcohol consumption and mean years of schooling had the most data gaps, with a missing analysis of 10.2% and 7.8% respectively. This was addressed using standard linear interpolation with linear extrapolation outside of the known data range.
Table 2
Regression coefficients of model estimations.
| Explanatory Variables | Model 1 – Life expectancy coefficient (t-ratio) | Model 2 – Life expectancy coefficient (t-ratio) |
|---|---|---|
| Health Expenditure | 0.0023 (2.6494) | 0.0027 (2.8082) |
| Out-of-pocket Expenditure | 0.0015 (1.9770) | 0.0009 (0.8500) |
| Income | 0.0064 (4.9465) | 0.0146 (7.4467) |
| Education | 0.0132 (5.4185) | 0.0190 (7.7176) |
| Food Production | –0.0007 (–1.9799) | –0.0021 (–2.4424) |
| Urbanization | 0.3537 (46.3057) | 0.2385 (22.3734) |
| CO2 emissions | 0.0019 (2.2721) | –0.0002 (–0.2572) |
| Water Access | –0.0156 (–1.7724) | 0.1054 (8.1903) |
| Sanitation Access | 0.0402 (6.9397) | 0.0471 (8.4221) |
| Alcohol Consumption | 0.0000 (0.1579) | –0.0003 (–0.7965) |
| Intercept | 2.6208 (0.0467) | 2.5203 (0.0322) |
| Observations (countries) | 1040 (52) | 780 (52) |
| NRMSE Accuracy | 0.985 | 0.990 |
| R2 | 0.813 | 0.911 |
[i] Model 1 = Generalized least square regressions, with country-fixed effects, error terms following a country-specific AR(1) and correction for heteroskedasticity. Model 2 = As Per model 1, with 5-year, lagged explanatory variables. NRMSE = normalized root mean square error. R2 = Efron’s pseudo r-squared.
Table 3
Relative contributions of the explanatory variables to life expectancy gains over time: 1995 to 2009 (from estimated coefficients in Table 2).
| Explanatory variables | Regression Coefficient1 | Contribution to Life Expectancy | 1995 Value | 2009 Value | |
|---|---|---|---|---|---|
| % | Months | ||||
| Health Expenditure | 0.0027** | 0.21 | 1.4 | 123.6 | 264.8 |
| Out-of-pocket Expenditure | 0.0009 | ns | ns | 43.9 | 37.4 |
| Income | 0.0146** | 1.11 | 7.7 | 2403.8 | 5154.9 |
| Education | 0.0190** | 0.51 | 3.5 | 3.6 | 4.7 |
| Food Production | –0.0021* | –0.02 | –0.13 | 94.6 | 103.7 |
| Urbanization | 0.2385** | 3.36 | 23.1 | 35.8 | 41.3 |
| CO2 emissions | –0.0002 | ns | ns | 0.9 | 1.2 |
| Water Access | 0.1054** | 1.56 | 10.7 | 62.1 | 72 |
| Sanitation Access | 0.0471** | 0.67 | 4.6 | 33.9 | 39.1 |
| Alcohol Consumption | –0.0003 | ns | ns | 2.9 | 3.1 |
| Countries Average | 687.6 | ||||
[i] 1 = model 2, with 5-year, lagged explanatory variables. Regression based on 780 Observations across 52 countries. Significant code: ** indicates significance at 1%; * indicates at 5%; ‘ns’ indicates not significant.
Figure 1
Life expectancy gains associated with percentage change in explanatory variables over time.
°indicates not significant.
Table I
Alternative model specification excluding GDP per capita.
| Explanatory Variables | Full Model1 | Model excluding Income2 |
|---|---|---|
| Health Expenditure | 0.0027 (2.8082) | 0.0041 (4.6023) |
| Out-of-pocket Expenditure | 0.0009 (0.8500) | –0.0000 (–0.0136) |
| Education | 0.0190 (7.7176) | 0.0281 (10.0765) |
| Food Production | –0.0021 (–2.4424) | –0.0013 (–1.4477) |
| Urbanization | 0.2385 (22.3734) | 0.2811 (26.5612) |
| CO2 emissions | –0.0002 (–0.2572) | 0.0011 (1.1730) |
| Water Access | 0.1054 (8.1903) | 0.0412 (5.2916) |
| Sanitation Access | 0.0471 (8.4221) | 0.0686 (12.2647) |
| Alcohol Consumption | –0.0003 (–0.7965) | –0.0001 (–0.6496) |
| Income | 0.0146 (7.4467) | |
| Intercept | 2.5203 (0.0322) | 2.5710 (0.0293) |
| Observations (countries) | 780 (52) | 780 (52) |
| NRMSE Accuracy | 0.990 | 0.990 |
| R2 | 0.911 | 0.907 |
[i] 1 GLS Model, with country-fixed effects, error terms following a country-specific AR(1) and correction for heteroskedasticity, with 5-year lagged explanatory variables.
2 As per full model specification, excluding income (GDP per capita).
Table II
Definition and sources of all variables.
| Variable | Definition | Aggregation Method | Source |
|---|---|---|---|
| Life expectancy at birth, total (years) | Life expectancy at birth indicates the number of years a newborn infant would live if prevailing patterns of mortality at the time of its birth were to stay the same throughout its life. | Total (years) Weighted average | World Bank |
| Health expenditure per capita | Total health expenditure is the sum of public and private health expenditures as a ratio of total population. It covers the provision of health services (preventive and curative), family planning activities, nutrition activities, and emergency aid designated for health but does not include the provision of water and sanitation. | PPP (constant 2011 international $) Weighted average | World Bank |
| Out-of-pocket expenditure | Out of pocket expenditure is any direct outlay by households, including gratuities and in-kind payments, to health practitioners and suppliers of pharmaceuticals, therapeutic appliances, and other goods and services whose primary intent is to contribute to the restoration or enhancement of the health status of individuals or population groups. It is a part of private health expenditure. | % of total expenditure on health Weighted average | World Bank |
| Gross domestic product – GDP, PPP (constant 2011 international $) | PPP GDP is gross domestic product converted to international dollars using purchasing power parity rates. GDP is the sum of gross value added by all resident producers in the economy plus any product taxes and minus any subsidies not included in the value of the products. | PPP (constant 2011 international $) Weighted average | World Bank |
| Mean years of schooling population 25+ years | An average number of completed years of education of a country’s population aged 25 years and older, excluding years spent repeating individual grades. | Total (years) Weighted average | UNESCO Institute for Statistics |
| Food Production index (Production Indices) | Food production index covers food crops that are considered edible and that contain nutrients. Coffee and tea are excluded because, although edible, they have no nutritive value. | Gross per capita Production Index Number (2004–2006 = 100): International US$ | Food and Agriculture Organization of the United Nations (FAO) |
| Urban population (% of total) | Urban population refers to people living in urban areas as defined by national statistical offices. | % of population Weighted average | World Bank |
| CO2 emissions (metric tons per capita) | Carbon dioxide emissions are those stemming from the burning of fossil fuels and the manufacture of cement. They include carbon dioxide produced during consumption of solid, liquid, and gas fuels and gas flaring. | Metric tons per capita | World Bank |
| Improved water source (% of the population with access) | Access to an improved water source refers to the percentage of the population using an improved drinking water source. The improved drinking water source includes piped water on premises (piped household water connection located inside the user’s dwelling, plot or yard), and other improved drinking water sources (public taps or standpipes, tube wells or boreholes, protected dug wells, protected springs, and rainwater collection). | % of population Weighted average | World Bank |
| Improved sanitation facilities (% of the population with access) | Access to improved sanitation facilities refers to the percentage of the population using improved sanitation facilities. Improved sanitation facilities are likely to ensure hygienic separation of human excreta from human contact. They include flush/pour flush (to the piped sewer system, septic tank, pit latrine), ventilated improved pit (VIP) latrine, pit latrine with slab, and composting toilet. | % of population Weighted average | World Bank |
| Total alcohol consumption per capita (liters of pure alcohol, projected estimates, 15+ years of age) | Total alcohol consumption per capita is based on projections for the amount of alcohol consumption (liters of pure alcohol) per person ages 15+ per year. | Liters of alcohol consumed per capita. Weighted average | World bank |