How much more inclusive has access to health and education become in recent decades? Are we on track for global convergence in human capital, well-being, and productivity—or will we need substantial increases in education and health investments to achieve that goal during the 21st century?
In a new study, World Inequality Lab researchers Nitin Bharti, Amory Gethin, Thanasak Jenmana, Zhexun Mo, Thomas Piketty, and Li Yang investigate the relationship between human capital, inequality of opportunity, and global productivity convergence.
The study draws on a new global historical database on public expenditure and revenue and their components—particularly education and health expenditure. This is the first database of its kind to cover all world regions over the period from 1800 to 2025.
KEY FINDINGS
- Total public expenditure rose from about 3% of global GDP in 1800 to around 31% today. The world’s richest regions—Europe and North America/Oceania—have consistently had higher levels of public spending (see Figure 2). This long-term rise is largely driven by the expansion of the “global social state”, supported by states’ growing capacity to collect direct income taxes and social contributions. In the 19th century, public spending was mostly devoted to military needs and basic services such as justice, policing, administration, and infrastructure. Spending on health, education, and social protection was almost non-existent in the early 20th century (see figure 3).
- Over the past two centuries, human capital expenditure (as % of GDP) have largely increased in all parts of the world, but with enormous and persistent inequality between regions (see Figures 8a, b, c and Figures 9a, b, c) .
- Public education expenditure per school-age individual in Sub-Saharan Africa is about 3% of the level observed in Europe and North America in 2025 in PPP terms.
- If we were to provide all children worldwide with the same average expenditure on education and health as is currently available in Europe and North America, it would cost 32% of the world’s GDP.
- Over the 1800-2025 period, human capital expenditure has had a large impact on productivity growth. Estimated returns are around 10% or more. Returns are higher for education than for health, and for public spending compared to private. Returns are especially large in poorer countries (those with productivity below €10 PPP/hour), with an annual return of 15-20% or more (see Table 5).
- Based on these historical trends, the paper explores future scenarios:
- In a “business-as- usual” scenario – where human capital expenditure stops rising and remains at 2010-2025 levels, the productivity gaps will persist. Productivity in Sub-Saharan Africa would remain around 9€/hour compared to 80€/hour in Europe and North America/Oceania (see Figure 17b).
- In a more optimistic scenario – where public and private education and health expenditure converge toward 38% of GDP in all countries, average global productivity would increase to around 100€/hour in all regions compared to 16€/hour at the global level today (see Figure 16b). All countries and regions would be better off. For example, the US would be better off with an hourly productivity equal to 120€ rather than 80€, even though this would require spending 38% of its GDP on human capital each year. Sub-Saharan Africa would require spending 38% of its GDP on human capital expenditure rather than 8% to achieve an hourly productivity of 100€ rather than 9€.
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
This paper is the third in a series of research papers and technical notes that will form the backbone of the Global Justice Report, due to be released in June 2026.
AUTHORS
- Nitin Bharti, NYU Abu Dhabi & WIL
- Amory Gethin, World Bank & WIL
- Thanasak Jenmana, PSE & WIL
- Zhexun Mo, CUNY & WIL
- Thomas Piketty, PSE & WIL
- Li Yang, ZEW & WIL
MEDIA CONTACT
- Alice Fauvel, Communications Manager, alice.fauvel[at]psemail.eu ; press[at]wid.world
