Endogenous versus exogenous drivers of the ancient–modern ECI correlation

Determine whether the significant positive correlation between the Economic Complexity Index rankings of modern countries covered by the Roman Empire—computed using (i) occupational data extracted from 1st–4th century CE Latin inscriptions and (ii) 1962–2022 UN Comtrade trade data—is explained by endogenous persistence of economic complexity across centuries or by exogenous determinants such as geographic positioning, trade node location, or natural resource endowments.

Background

The paper reconstructs the occupational structure of Roman provinces from over 525,000 Latin inscriptions, builds an Occupation Space, and computes an Economic Complexity Index (ECI) for provinces. It then maps these to modern countries and compares ancient ECI (from inscriptions) with modern ECI (from UN Comtrade SITC Rev 2 trade data, 1962–2022), finding a significant positive rank correlation.

While the correlation indicates temporal stability of relative economic complexity, the mechanism behind this stability is unresolved. The authors explicitly note they cannot determine whether the observed correlation arises from endogenous persistence of economic capabilities or from exogenous factors such as geography and natural resources. Clarifying this mechanism is central to understanding long-run development and the difficulty of changing economic capability endowments.