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Catching Bid-rigging Cartels with Graph Attention Neural Networks

David Imhof, Emanuel W Viklund, Martin Huber

arXiv 16 Jul 2025 · Econometrics

arXiv:2507.12369 · PDF · DOI · OpenAlex · Extracted main text

Abstract

We propose a novel application of graph attention networks (GATs), a type of graph neural network enhanced with attention mechanisms, to develop a deep learning algorithm for detecting collusive behavior, leveraging predictive features suggested in prior research. We test our approach on a large dataset covering 13 markets across seven countries. Our results show that predictive models based on GATs, trained on a subset of the markets, can be effectively transferred to other markets, achieving accuracy rates between 80% and 90%, depending on the hyperparameter settings. The best-performing configuration, applied to eight markets from Switzerland and the Japanese region of Okinawa, yields an average accuracy of 91% for cross-market prediction. When extended to 12 markets, the method maintains a strong performance with an average accuracy of 84%, surpassing traditional ensemble approaches in machine learning. These results suggest that GAT-based detection methods offer a promising tool for competition authorities to screen markets for potential cartel activity.

Citation extraction

48
references
125
in-text mentions
48
distinct cited
7
self-citations
11,513
main-text words

appendix boundary found by appendix_titled_section at “Appendix A: Statistical features” · 84% of the source is main text. Read the extracted text to check this.

Most heavily cited references

The works this paper leans on most, across its whole bibliography — not restricted to papers in our corpus. Ranked by composite intensity, which combines how often a work is mentioned, how many sections mention it, and how much of that falls in the main text rather than the appendix.

ReferenceIntensityMentionsSectionsMain text
1Aaltio, A., R. Buri, A. Jokelainen, and J. Lundberg, Complementary b… (2025)1.00073100%
2Aryal, G., and M. F. Gabrielli, Testing for collusion in asymmetric… (2013)1.00064100%
3Garcia, M. J. R., V. R. Montequin, F. O. Fernandez, and J. M. V. Bal… (2022)1.00053100%
4Wallimann, H., M. Huber, and D. Imhof, A machine learning approach f… (2022)0.9619589%
5Huber, M., D. Imhof, and R. Ishii, Transnational machine learning wi… (2022) self0.92815680%
6Huber, M., and D. Imhof, Machine learning with screens for detecting… (2019) self0.88810470%
7Imhof, D., and H. Wallimann, Detecting bid-rigging coalitions in dif… (2021) self0.87452100%
8Imhof, D., Detecting bid-rigging cartels with descriptive statistics… (2020) self0.8434375%
9Anysz, H., A. Foremny, J. Kulejewski, and A. Nical, Collusion and bi… (2018)0.81142100%
10Huber, M., and D. Imhof, Flagging cartel participants with deep lear… (2023) self0.81142100%

Showing the top 10 of 48 scored citations.