Paper #1927

Title:

Keeping in the dark with hard evidence

Authors:

Daniel Bird and Alexander Frug

Date:

October 2025

Abstract:

We present a dynamic learning setting in which the periodic data observed by the decision-maker is mediated by an agent. We study when, and to what extent, this mediation can distort the decision-maker’s long-run learning, even though the agent’s reports are restricted to consist of verifiable hard evidence and must adhere to certain standards. We introduce the manipulation-proof law of large numbers – that delivers a sharp dichotomy: when it holds, the decision-maker’s learning is guaranteed in the long-run; when it fails, the scope for manipulation is essentially unrestricted.

Keywords:

manipulation , selective forced disclosure , long-run beliefs

JEL codes:

D83

Area of Research:

Microeconomics

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