A new study draws on more than 900 million linked employer–employee records covering the entire formal workforce of Brazil to examine when cities provide upward mobility for the initially poor.

The researchers find that upward mobility for low-wage workers is strongest in workplaces that combine low-wage individuals with high-wage workers. This association is particularly pronounced in Brazil's southern cities, where more complex industries employ workers with a wider range of skills. The association is weaker in northern cities, where formal employment is dominated by the public sector. In practical terms, the paper is aimed at a long-running question in urban economics: whether the mix of jobs inside a city matters as much as the city’s overall size or income level when it comes to economic advancement.

The paper is by Radu Barza, Edward Glaeser, César A. Hidalgo, and Martina Viarengo, and appears in the Proceedings of the National Academy of Sciences (PNAS), a peer-reviewed scientific journal. Glaeser is a Harvard economist known for his research on cities and urban economies. A useful thread on the paper has also been shared on X.

Writing on the economics blog Marginal Revolution, the post's author called the study "one of the best and most important economics papers I have seen in the last few years."

The findings point to a notable regional divide within Brazil: in the south, workplaces in more complex industries that mix low-wage and high-wage workers are associated with stronger upward mobility, while in the north — where public-sector employment dominates the formal labor market — that association is weaker.