Population density and its effect on economic activity have long been of interest to scholars. This column develops a new measure of land quality which takes into account agricultural productivity, biomes, proximity to the sea, navigable rivers, large lakes, natural harbours, terrain roughness, and elevation. The measure is used to compute quality-adjusted land area as well as population density for each country in the world. Correlating quality-adjusted population density with income per capita, it finds a starkly negative relationship, which is suggested to be the result of differential population growth between poor and rich countries over the last 200 years.
https://voxeu.org/article/adjusting-population-density-account-land-quality
