Jul 18, 2026
The Excel Error That Ran the World
In early 2013 a third-year economics PhD student at the University of Massachusetts Amherst was given a routine assignment: take a famous empirical paper and try to reproduce it. Thomas Herndon, then 28, picked the most influential macroeconomics paper of the decade. He could not make the numbers come out. He emailed the authors, and to their considerable credit they sent him their original working spreadsheet.







