A log-linear regression of life expectancy on GDP per capita explains 74.6% of all cross-national variation in health outcomes — confirming the Preston Curve as the dominant global development pattern. Each 2.7-fold increase in national income is associated with 7.91 additional years of life expectancy (p=0.0000). Asia made the most dramatic gains, with median life expectancy rising by 25.9 years between 1952 and 2007. The dataset covers 34 countries across 5 continents.

The Preston Curve scatter for 2007 plots 34 countries coloured by continent, with bubble size proportional to population. Log-linear regression explains 74.6% of the variance in life expectancy across countries, confirming that national wealth is the single strongest predictor of population health outcomes. Countries in high-income 5 continents cluster in the upper-right, while lower-income nations occupy the steeply-sloped portion of the curve where each additional dollar of GDP yields the largest health gains.

Median life expectancy has risen in every continent between 1952 and 2007. Asia recorded the largest gain of 25.9 years — the most dramatic health improvement of any world region over this period. Oceania improved by the smallest margin (8.6 years), though this still reflects meaningful progress given its already-high baseline. The trend lines show no sustained reversals, though growth rates slowed in some regions during the 1980s and 1990s.

In 2007, Oceania had the highest median GDP per capita at $25,896, compared to $1,278 in Africa — a 20.3× gap between the wealthiest and poorest world regions. This economic divide directly maps onto the continental life expectancy disparities visible in the Preston Curve scatter plot. Closing this GDP gap even partially would, based on the regression model, translate into measurable improvements in population health outcomes.

The box plots reveal the spread of life expectancy across individual countries within each continent, pooling all available years of data. 5 continents are shown; Asia exhibits the widest interquartile range (14.8 years), indicating the greatest inequality in health outcomes among its member countries. Continents with narrow distributions have more uniform health standards, while wide spreads point to pockets of very high and very low life expectancy coexisting within the same region.

In 2007, New Zealand led the world with a life expectancy of 80 years — the highest among all 34 countries in the dataset. Of the top 20 countries by longevity, 8 are from Europe, confirming that high-longevity leaders cluster in particular continents. The ranking highlights both the geographic concentration of health success and the role of institutional development, diet, and social cohesion in achieving lifespans that exceed what GDP alone would predict.

The continental development profile for 2007 benchmarks each world region on three key metrics: total population, median GDP per capita, and median life expectancy. Asia has the largest population, Oceania the highest median income, and Oceania the longest median lifespan. Comparing income and longevity columns side-by-side reveals which continents deliver health outcomes above or below what their GDP level would predict — the signature of efficient (or inefficient) development pathways.