Writing Code vs. Shipping Code: Productivity Effects Across Generations of AI Coding Tools

The transformative power of LLMs in coding has been irrefutable, and it feels like we are living through a magical computing renaissance. On the socials, we hear impressive numbers of lines of code generated, features delivered, and bugs fixed. But, the macroeconomic indicators seem to be still lagging. Heck, if you talk with an engineering manager, you find that their product shipping dates haven't miraculously compressed by a factor of five, either.This paper just landed 10 days ago. It is from MIT and Wharton by Mert Demirer, Leon Musolff, and Liyuan Yang. Their study attempts to provide a structured economic model for evaluating actual productivity obtained from AI coding tools. By pairing confidential Microsoft telemetry with the public footprints of over 100,000 GitHub developers (tracking everything from open-source utilities to web app repositories), the authors show significant systemic friction downstream of AI code generation.Of course, I do my usual skeptical critic of the…