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A global project rewrites the origins of economic inequality from an archaeological dataset to investigate inequality in the long run. Mattia Fochesato is among the researchers involved

What does the foundation of a prehistoric house tell us about the wealth of its owner? More than you might think. It is from this simple question that the GINI project - Global Dynamics of Inequality - one of the most ambitious scientific endeavors ever undertaken to reconstruct the economic dynamics of the distant past, takes its cue. The result has just been published in a special issue of the prestigious journal PNAS, and represents a breakthrough for archaeology, economic history and the social sciences in general.

Underlying the project is an extraordinary dataset: about 45,000 dwellings analyzed in more than 1,000 archaeological observations from around the world: from more than 20,000 years ago in West Asia to the 20th century in Melanesia. The data include living areas and, when possible, storage capacities, used as proxies for material wealth. The researchers calculated site-by-site Gini coefficients to estimate levels of inequality within past communities.

But the GINI project is not limited to historical reconstruction. Indeed, one of the goals is to understand whether and how these same metrics-the distribution of housing size, in particular-are still an effective indicator of economic inequality today. The researchers compared archaeological data with large contemporary housing databases and associated economic indicators.

“This allows us to come full circle, comparing archaeology with the present,” points out Mattia Fochesato, economic historian and assistant professor at Bocconi University's Department of Social and Political Sciences, co-author of three articles in the special issue. “We are trying to understand whether the mechanisms that link the shape of settlements to the distribution of wealth still work today, and to what extent the regularities we observe in the past speak to us about contemporary societies. Economic inequality is not just a problem of today,” Fochesato adds, “it is a structural expression of the ways in which humans produce, accumulate and transmit resources over time. Studying these processes over the long term helps us recognize the forces that generate them, even in the present.”

When land beats work

In the first study, Labor, land, and the global dynamics of economic inequality, Fochesato and colleagues test a fundamental economic model: societies in which production is constrained by land rather than labor tend to exhibit higher levels of inequality. This is because land - or other inheritable material goods such as draught livestock - can be accumulated and passed on between generations, unlike free human labor.

The analysis, conducted on hundreds of sites classified by type of production regime, shows that “land-limited” societies have significantly higher Gini than “labor-limited” societies. And the figure holds true across continents, from the Inca agricultural terraces of South America to the irrigated countryside of Mesopotamia.

“The transition from labor-based to land-based regimes is not only related to agriculture per se,” Fochesato points out. “It matters how production is organized, whether there are traction animals, irrigation systems, whether the surplus is concentratable. These factors have long-term effects on the distribution of wealth.”

Hierarchies that generate inequality

In the second study of which Fochesato is co-author, Economic inequality is fueled by population scale, land-limited production, and settlement hierarchies across the archaeological record, we show how the expansion of societies in terms of population scale and political structure is another powerful driver of inequality.

Using indicators such as the number of hierarchical levels in settlement systems and the relative position of sites (“basal” or “apex”), the study shows that inequality tends to increase in larger and more connected centers. The highest Gini are found in sites at the top of regional hierarchies, while the most peripheral villages remain more egalitarian, even centuries after the introduction of agriculture.

“It's not just the economy that matters,” Fochesato explains. “When population grows, the opportunities to concentrate power also grow, and inequality is amplified. Settlement hierarchies become tools of accumulation for local elites.”

The effect is even more pronounced in societies that adopt complex political systems with centralized institutions or structured business networks. The project calls this process the polity-scale effect: the larger and more complex the political organization, the greater the potential for inequality.

Measuring inequality at multiple levels

In the third study, Toward multiscalar measures of inequality in archaeology, authored by Enrico Crema, Fochesato and others, the team addresses a crucial methodological issue: the scale of observation matters. So far, most analyses of inequality have focused on the single site. But what happens when we broaden our gaze to a region or an entire cultural system?

The paper proposes a three-level model:

  • α-inequality: the inequality within each site;
  • β-inequality: the variation in inequality among different sites in the same region;
  • γ-inequality: the aggregate inequality at the regional level.

The study shows that γ-inequality can be much higher than the average local Gini, especially in complex societies where large cities coexist with much more modest rural settlements. This gap (δ-inequality) becomes a valuable indicator for understanding how much a society concentrates wealth in a few urban elites.

“Looking only at the local site can make us miss the complexity of regional inequalities,” Fochesato comments. “In contrast, multiscalar comparison shows us where and when wealth accumulates in a systematic way.”

An archive for the future

The GINI project is not just a data collection: it is a new scientific infrastructure for investigating the historical origins of economic inequality. The database-which continues to grow-includes sites from regions largely overlooked in previous studies, such as sub-Saharan Africa, South Asia, the Andes and Melanesia. It is based on systematic analysis of housing areas and storage capacities, supplemented by cultural, political and environmental indicators, and supported by a broad interdisciplinary research network.

The project is led by: Amy Bogaard (University of Oxford); Timothy A. Kohler (Santa Fe Institute); and Scott Ortman, (Santa Fe Institute). 

The main funding for the project comes from the National Science Foundation, with additional support from the Coalition for Archaeological Synthesis (CfAS) and the Center for Collaborative Synthesis in Archaeology (CCSA).

Also making the creation of a dataset of global scope possible was the collaboration of more than twenty academic and scientific institutions around the world: these include the University of Oxford, the Field Museum in Chicago, the University of Cambridge, CONICET in Argentina, the University of Bonn, and, for Italy, Bocconi University through the Dondena Centre for Research on Social Dynamics and Public Policy and the Bocconi Institute for Data Science and Analytics (BIDSA).

“Studying inequality in the long run helps us see the regularities behind the complexity,” Fochesato concludes. “Not to justify the present, but to understand its deep roots. It is also a way to reflect on which societies have been able to limit the concentration of wealth - and why.”

Research