Calibrated Net Influence for Collusion Detection: Confounders, Masking and LLM Agents
Francise Liang
Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
Net influence (Bonjour et al. 2022) flags a colluding pair from action logs with a fixed 0.05-bit threshold. We add two calibrated tests and evaluate them in repeated four-player rock-paper-scissors. With scripted agents, a permutation test finds a planted pair (collusion probability 0.2, 1,200 rounds) in 98.5% of runs, against 46.5% for the fixed threshold, but with no collusion accuses some pair in 55.5% of runs where two followers copy one leader. A bootstrap test of whether a pair stands out keeps observed false accusations at or below 5% under four of five confounders, but cannot find colluders when a third player copies one of them more strongly than the partner does. With Kimi agents, instructed pairs lose points and honest pairs are about as dependent; tests that sometimes single out the colluders also single out an honest pair, and the bootstrap test never flags them.
Reviews
The project highlights useful limitations of existing detectors, particularly how they can flag honest players while missing actual colluders. The masking scenario is especially interesting. The experiments are reasonably thorough, and the authors are transparent about limitations. My main concern is that the LLM colluders actually lost points, so it's unclear whether the method can detect successful collusion. Testing this across more models would strengthen the work.
Cite this project
@misc{liang2026calibrated,
title = {{Calibrated Net Influence for Collusion Detection: Confounders, Masking and LLM Agents}},
author = {Francise Liang},
year = {2026},
month = oct,
note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/calibrated-net-influence-for-collusion-detection-confounders-masking-and-llm-agents-qj76}},
url = {https://apartresearch.com/sprints/projects/calibrated-net-influence-for-collusion-detection-confounders-masking-and-llm-agents-qj76}
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