Global Economic Inequality

OWID presents work from many different people and organizations. When citing this entry, please also cite the original data source. This entry can be cited as:

Max Roser (2016) – ‘Global Economic Inequality’. Published online at Retrieved from: [Online Resource]

This data entry is concerned with the inequality of global interpersonal income.

# Empirical View

# Global divergence followed by convergence – Economic history in one chart

This chart shows the distribution of the annual income between all world citizen. To make incomes comparable across countries and across time the annual incomes are measured in International Dollars – this is a currency that would would buy a comparable amount of goods and services a U.S. dollar would buy in the United States in 1990.

The distribution of incomes is shown at 3 points in time:

  • In 1820 only few countries achieved economic growth. The chart shows that the majority of the world lived in poverty with an income similar to the poorest countries in Africa today (around 500 International Dollars). The data entry on global poverty shows that in 1820 between 85% and 95% of the world lived in absolute poverty.
  • In the year 1950, 150 years later, the world has changed – it became very unequal. The world income distribution has become bimodal. It has the shape of a camel. One hump at around 500 International Dollars and a second hump at around 5,000 International Dollars – the world was divided into a poor developing world and a 10-times richer developed world.
  • Over the following 3 decades the world income distribution has again changed dramatically. The poorer countries, especially in South-East Asia, have caught up. The two-humped camel shaped has changed into a one-humped dromedar shape. World income inequality has declined. And not only is the world more equal again, the distribution has also shifted to the right – the world is much richer.
# World income distribution, 1820, 1970 and 2000 – Max Roser1

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# Global income inequality increased for 2 centuries and is now falling

The visualization below shows the distribution of incomes between 1988 and 2011. The data was compiled by the economists Branko Milanovic and Christoph Lakner.2
To see the change over time select the years just above the distribution.
The previous visualization that showed the the change from the year 1820 to the year 2000 is based on estimates of inflation-adjusted average incomes per country (GDP per capita) and a measure of income inequality within a country only. It gives us a rough idea of how the distribution of incomes changed, but it is not very detailed and not very precise. In contrast to this the work by Branko Milanovic and Christoph Lakner is based on much more detailed household survey data. This data is measuring household income at each decile of the income distribution and the two authors used this information to arrive at the global income distribution. The downside of this approach is that we can only go as far back in time as household surveys were conducted.
The visualization shows the end of the long era in human history in which global inequality was increasing. Starting with the industrialization in North-Western Europe incomes in this part of the world started to increase while material prosperity in the rest of the world remained low. While some countries followed the European industrialization – first Northern America, Oceania, and parts of South America and later Japan and East Asia – other countries in Asia and Africa remained poor. As a consequence of this global inequality increased over a long period of time. Only in the period shown in the visualization below did this change: With rapid growth in much of Asia in particular did the global distribution of incomes become less unequal. The incomes of the poorer half of the world population rose faster than the incomes of the richer half of the world population.


# Global inequality between world citizens and its components 1820-1992 – Max Roser3

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# Within-country income percentiles vs world income percentiles by country – Milanovic (2010)4



# World distribution of income by world region, 1970 and 2006 – Sala-i-Martin & Pinkovskiy (2010)5

World-Distribution-of-Income-by-Region,-1970 – Sala-i-Martin-&-Pinkovskiy-(2010)

World-Distribution-of-Income-by-Region,-2006 – Sala-i-Martin-&-Pinkovskiy-(2010)


# World distribution of income, 1970-2006 – Sala-i-Martin & Pinkovskiy (2010)6

World-Distribution-of-Income,-1970-2006 – Sala-i-Martin-&-Pinkovskiy-(2010)


# World inequality in different measures and world GDP per capita, 1970-2006 – Sala-i-Martin & Pinkovskiy (2010)7

Before the publication of the previously shown paper, the economists Sudhir Anand and Paul Segal reviewed the research literature on the distribution of global income inequality. In this very thorough study, that is still interesting and very relevant, the author found ‘no consensus regarding the direction of change’ showing that ‘findings of a rise or fall in global income inequality are not robust across different estimation methods and datasets’.8

# Maps – Current World Income Distribution

# World map of GDP per square km – Gallup and Sachs (1999)9
World-Map-of-GDP-per-square-km– Gallup-and-Sachs-(1999)

# World GDP density map, 1990 and 2025 – SEDAC (NASA)10

World GDP Density Map 1990 and 2025 – SEDAC (NASA)0

# Economic Convergence between Countries

# Strong convergence in Europe, 1950-2006 – World Development Report (2009)11

Strong Convergence in Europe between 1950 and 2006 – World Development Report (2009)


# Annual real GDP growth in poorer and richer countries, 1961-2013 – Max Roser12

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# GDP accumulated change, 1990-2006 – Wikipedia (originally from the IMF)13
GDP accumulated change (1990-2006) – Wikipedia (from IMF originally)

# Past Level of GDP and Subsequent Growth

# Growth vs initial income (population-weighted) – Sala-i-Martin (2006)14
Growth Versus Initial Income (Population-Weighted) – Sala-i-Martin (2006)

# Growth of Given Size by Time – Speed of Catching up

# Years for income per capita to grow from $2,000 to $4,000 (1990$ US) – Aghion & Durlauf [Eds.] (2006)15
Years for income per capita to grow from 2,000 to 4,000 (1990$ US) – Aghion & Durlauf [Eds.] (2006)

# Number of years for GDP per person to double, 1700-2040 – The Economist16
Number of years for GDP per person to double (1700-2040) – The Economist


# Shares of world GDP (% of world total), 1700-2030 – Max Roser17

# The world’s shifting economic center of gravity, 1 CE – 2025 CE – Oxford Martin School (2013)18
The world's shifting economic centre of gravity (1 CE - 2025 CE) – Oxford Martin School (2013)

# Present World and Future

Wikipedia’s list of estimates of real gross domestic product growth rate for the latest available year is here.

# Data Quality & Definition

# Growth convergence vs absolute income convergence, 1990-2003 – Todaro & Smith (2011)19
Growth Convergence versus Absolute Income Convergence (1990 to 2003) – Todaro & Smith (2011)
The already mentioned study by Sudhir Anand and Paul Segal is a very good review of this topic.20

# Total and between inequality: comparisons of different studies – Liberati (2013)21

Total-and-Between-Inequality-–-Comparisons-of-different-Studies-– Liberati-(2013)0

# Data Sources

# Clio-Infra Database
  • Data: Various economic and social indicators, including income inequality
  • Geographical coverage: Global
  • Time span: Depends on indicator being used
  • Available at: Online here