Public Persuasion with Endogenous Fact-Checking

TL;DR

This paper analyzes how the cost of fact-checking influences a sender’s strategy in public persuasion, showing that cheaper verification leads to less informative signals to reduce scrutiny, with implications for transparency and repression.

Contribution

It introduces a model of Bayesian persuasion with endogenous, heterogeneous fact-checking costs, revealing how verification technology impacts information design and manipulation strategies.

Findings

Cheaper verification reduces the informativeness of public signals.

Lower verification costs increase the likelihood of manipulation and repression.

The framework predicts co-movement of transparency, manipulation, and repression with verification technology.

Abstract

We study public persuasion when a sender communicates with a large audience that can fact-check at heterogeneous costs. The sender commits to a public information policy before the state is realized, but any verifiable claim she makes after observing the state must be truthful (an ex-post implementability constraint). Receivers observe the public message and then decide whether to verify; this selective verification feeds back into the sender's objective and turns the design problem into a constrained version of Bayesian persuasion. Our main result is a reverse comparative static: when fact-checking becomes cheaper in the population, the sender optimally supplies a strictly less informative public signal. Intuitively, cheaper verification makes bold claims invite scrutiny, so the sender coarsens information to dampen the incentive to verify. We also endogenize two ex-post instruments - continuous falsification and fixed-cost repression - and characterize threshold substitutions from persuasion to manipulation and, ultimately, to repression as monitoring improves. The framework provides testable predictions for how transparency, manipulation, and repression co-move with changes in verification technology.