
Experimentally Validated Digital Twins with Raj Chetty & Jamie Fogel | Ep. 168
Follow the link for the full summary: https://markusacademy.substack.com/p/experimentally-validated-digital Link to sign up for the webinar series: https://markusacademy.substack.com/ Watch on Youtube: https://youtu.be/UlJGLmLoVLI Paper: https://opportunityinsights.org/paper/digital-twins/ Raj Chetty and Jamie Fogel joined Markus' Academy to present their new paper, "Experimentally Validated Digital Twins: Evaluating Workforce Training Programs in the Age of Big Data". Chetty is a Professor of Economics at Harvard University and the Director of Opportunity Insights, where Fogel is a Research Scientist. A summary in three bullets: ● The US has more than 5,000 workforce training programs. Fewer than 1% have been evaluated in a randomized controlled trial (RCT) because trials are expensive ● Chetty et al. (2026) provides a toolbox to do policy evaluation based on observational data using machine learning ● In the age of big data, RCTs may be most valuable for validating observational models rather than for identifying treatment effects themselves Timestamps: [00:00] Big data and workforce training programs [12:21] Validation against 37 randomized trials [27:11] What changed since LaLonde (1986) [33:52] How results can differ across cities and years [45:51] What's next for applied economics and AI?