Science has long been concentrated in the Western world, but the global research landscape is undergoing a profound reorganization. Using data on 44 million publications from 1980 to 2022, we document the geography of science in terms of who produces it, what it studies, and where it diffuses....

Structural economic models, while parsimonious and interpretable, often exhibit poor data fit and limited forecasting performance. Machine learning models, by contrast, offer substantial flexibility but are prone to overfitting and weak out-of-distribution generalization. We propose a...

This study investigates the effects of artificial intelligence (AI) adoption in organizations. We ask: (1) How should a principal optimally deploy limited AI resources to replace workers in a team? (2) In a sequential workflow, which workers face the highest risk of AI replacement? (3) How does...

I describe nine implications of the interconnectedness of fiscal and monetary policy that surface in Heterogeneous Agent New Keynesian (HANK) models. Not all are unique to HANK models. (i) Long run fiscal changes force monetary adjustments. (ii) Sustainable permanent deficits are feasible. (iii)...