← Search

Quarterly Journal of Economics Vol. 140 No. 2 2025

The Diffusion of New Technologies

Aakash Kalyani1; Nicholas Bloom2; Marcela Carvalho3; Tarek A. Hassan4; Josh Lerner5; Ahmed Tahoun3

1 Federal Reserve Bank of St. Louis · 2 Stanford University and National Bureau of Economic Research · 3 London Business School · 4 Boston University and National Bureau of Economic Research , · 5 Harvard University and National Bureau of Economic Research

Abstract

We identify phrases associated with novel technologies using textual analysis of patents, job postings, and earnings calls, enabling us to identify four stylized facts on the diffusion of jobs relating to new technologies. First, the development of economically impactful new technologies is geographically highly concentrated, more so even than overall patenting: 56% of the most economically impactful technologies come from just two U.S. locations, Silicon Valley and the Northeast Corridor. Second, as the technologies mature and the number of related jobs grows, hiring spreads geographically. This process is very slow, taking around 50 years to disperse fully. Third, while initial hiring in new technologies is highly skill-biased, over time the mean skill level in new positions declines, drawing in an increasing number of lower-skilled workers. Finally, the geographic spread of hiring is slowest for higher-skilled positions, with the locations where new technologies were pioneered remaining the focus for the technology's high-skill jobs for decades.

DOI
10.1093/qje/qjaf002
Volume
140
Issue
2
Pages
1299-1365
Language
en
Sources
bibtex:phds-export.bib openalex crossref

Cite