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Marginal Revolution ·Behind the news

A Beautiful Theory Falls to Ugly Data

by Alex Tabarrok

Published 2026-05-26 11:16:47+00:00

If a seller can always lower their price tomorrow, what stops them from doing it today?

0:00 / 5:26 · Narrator Charon

Context

This piece from 26 May 2026 looks at a famous economic theory suggesting that prices for digital goods should crash almost instantly. The Coase Conjecture is elegant on paper, yet the reality of the e-book market tells a different story. The writing moves away from the abstract to ask why the data refuses to cooperate with the math. It considers whether firms are more disciplined than theorists expect, or if the simple presence of alternative ways to spend an afternoon keeps the old models from coming true.

Show notes

An empirical test of the Coase Conjecture—the theory that durable-good monopolists will rapidly lower prices to marginal cost—using data from the electronic book market. Comparing copyrighted prices with public domain benchmarks shows that the predicted rapid price decline does not occur. The analysis evaluates why the conjecture fails in practice, focusing on firm commitment and the role of consumer outside options.

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