History A comparison of income inequality in the Roman and Chinese Han empires

[Maciamo]

There is an interesting study comparing the regional income per capita and income inequality across the Roman Empire and the Han Empire. GDP per capita was considerably higher in the Roman Empire.

Nature: A comparison of income inequality in the Roman and Chinese Han empires

Abstract
The emergence of vast territorial empires is a recurring development in the history of human civilization. Their ability to extract resources from their subjects, and to redistribute them, also increases the potential of higher levels of economic inequality. Here we explore how imperial structures contributed to set the level of inequality in two ancient empires, the Roman Empire ca. 165 CE and the Chinese Han Empire ca. 2 CE. We estimate the overall levels of imperial inequality as the combination of inequality between and within regions. We find that the Han Empire was, overall, more unequal and extractive than the Roman Empire. Other empires, however, were even more extractive, as shown by a comparison with the Aztec Empire ca. 1492. We argue that higher inequality increased the potential for political instability and the collapse of empires.

The third map shows the inequality extraction ratio, a concept that measures the percentage of a country’s maximum potential inequality. That makes it a more accurate measurement of inequality than just income inequality like the Gini index.

 

[Maciamo]

I asked ChatGPT to measure the inequality extraction ratio for the modern United States so that we have a point of comparison for the Roman Empire and Han empire.

IER Formula Recap:​

IER = Observed Inequality / Maximum Feasible Inequality

Where:

• Observed Inequality = Gini coefficient (income-based, from current stats)
• Maximum Feasible Inequality = Theoretical Gini if elites took all income above subsistence for the rest of the population

Step 1: Observed Inequality (U.S.)​

From the U.S. Census Bureau (2023) and OECD:

• U.S. Gini coefficient (post-tax, post-transfer) ≈ 0.39–0.41

Step 2: Maximum Feasible Inequality​

This is more theoretical, but economists like Branko Milanović estimate that:

• The maximum feasible Gini for a modern developed country like the U.S. is about 0.60–0.65
  • Why? Because you can't push inequality beyond a point without threatening political/social stability or reducing productivity below subsistence.

Step 3: Calculate IER​

Let’s use:

• Observed Gini = 0.40
• Max Feasible Gini = 0.65

IER = 0.40 / 0.65 ≈ 0.615 → or 61.5%

Interpretation:​

• This means the U.S. is extracting around 61.5% of its maximum possible inequality.
• Compared to pre-modern societies where elites extracted 70–80%, the U.S. is high, but not maxed out.

Despite the huge income disparities in the US today, an IER of 61.5% is lower than the average of the Roman Empire. It would be in middle yellow on the map like Anatolia. Yet socio-economic inequalities were even higher in China.