Advancing Ad Auction Realism: Practical Insights & Modeling Implications (2307.11732v2)
Abstract: Contemporary real-world online ad auctions differ from canonical models [Edelman et al., 2007; Varian, 2009] in at least four ways: (1) values and click-through rates can depend upon users' search queries, but advertisers can only partially "tune" their bids to specific queries; (2) advertisers do not know the number, identity, and precise value distribution of competing bidders; (3) advertisers only receive partial, aggregated feedback, and (4) payment rules are only partially known to bidders. These features make it virtually impossible to fully characterize equilibrium bidding behavior. This paper shows that, nevertheless, one can still gain useful insight into modern ad auctions by modeling advertisers as agents governed by an adversarial bandit algorithm, independent of auction mechanism intricacies. To demonstrate our approach, we first simulate "soft-floor" auctions [Zeithammer, 2019], a complex, real-world pricing rule for which no complete equilibrium characterization is known. We find that (i) when values and click-through rates are query-dependent, soft floors can improve revenues relative to standard auction formats even if bidder types are drawn from the same distribution; and (ii) with distributional asymmetries that reflect relevant real-world scenario, we find that soft floors yield lower revenues than suitably chosen reserve prices, even restricting attention to a single query. We then demonstrate how to infer advertiser value distributions from observed bids for a variety of pricing rules, and illustrate our approach with aggregate data from an e-commerce website.
- Gambling in a rigged casino: The adversarial multi-armed bandit problem. In Proceedings of IEEE 36th Annual Foundations of Computer Science, pages 322–331. IEEE, 1995.
- Contextual bandits with cross-learning. arXiv preprint arXiv:1809.09582, 2018.
- M. Banchio and A. Skrzypacz. Artificial intelligence and auction design. In Proceedings of the 23rd ACM Conference on Economics and Computation, pages 30–31, 2022.
- D. Bergemann and S. Morris. Bayes correlated equilibrium and the comparison of information structures in games. Theoretical Economics, 11(2):487–522, 2016.
- Learning equilibria in symmetric auction games using artificial neural networks. Nature machine intelligence, 3(8):687–695, 2021.
- W. J. Choi and A. Sayedi. Learning in online advertising. Marketing Science, 38(4):584–608, 2019.
- Multi-channel autobidding with budget and roi constraints. arXiv preprint arXiv:2302.01523, 2023.
- First-price auctions in online display advertising. Journal of Marketing Research, 58(5):888–907, 2021.
- Internet advertising and the generalized second-price auction: Selling billions of dollars worth of keywords. American economic review, 97(1):242–259, 2007.
- Equilibria in auctions with ad types. In Proceedings of the ACM Web Conference 2022, pages 68–78, 2022.
- Learning to bid without knowing your value. In Proceedings of the 2018 ACM Conference on Economics and Computation, pages 505–522, 2018.
- Convergence analysis of no-regret bidding algorithms in repeated auctions. In Proceedings of the AAAI Conference on Artificial Intelligence, volume 35, pages 5399–5406, 2021.
- Y. Freund and R. E. Schapire. A decision-theoretic generalization of on-line learning and an application to boosting. Journal of computer and system sciences, 55(1):119–139, 1997.
- D. Fudenberg and D. K. Levine. The theory of learning in games. MIT press, 1998.
- D. Fudenberg and D. K. Levine. Learning and equilibrium. Annu. Rev. Econ., 1(1):385–420, 2009.
- Optimal bidding strategy without exploration in real-time bidding. In Proceedings of the 2020 SIAM International Conference on Data Mining, pages 298–306. SIAM, 2020.
- Bidding and pricing in budget and roi constrained markets. arXiv preprint arXiv:2107.07725, 8(8.1):3, 2021.
- Robust learning of optimal auctions. Advances in Neural Information Processing Systems, 34, 2021.
- Optimal no-regret learning in repeated first-price auctions. arXiv preprint arXiv:2003.09795, 2020.
- J. C. Harsanyi. Games with incomplete information played by “bayesian” players, i–iii part i. the basic model. Management science, 14(3):159–182, 1967.
- No-regret learning in bayesian games. Advances in Neural Information Processing Systems, 28, 2015.
- Learning to bid with auctiongym. Proceedings of the 28th ACM SIGKDD Conference on Knowledge Discovery and Data Mining AdKDD Workshop (AdKDD’22), 2022.
- A probabilistic framework to learn auction mechanisms via gradient descent. In AAAI 2023 Workshop on AI for Web Advertising, 2023. URL https://www.amazon.science/publications/a-probabilistic-framework-to-learn-auction-mechanisms-via-gradient-descent.
- M. Kanmaz and E. Surer. Using multi-agent reinforcement learning in auction simulations. arXiv preprint arXiv:2004.02764, 2020.
- Efficient learning by implicit exploration in bandit problems with side observations. In Advances in Neural Information Processing Systems, volume 27, 2014.
- V. Krishna. Auction theory. Academic press, 2009.
- T. Lattimore and C. Szepesvári. Bandit algorithms. Cambridge University Press, 2020.
- A theory of auctions and competitive bidding. Econometrica: Journal of the Econometric Society, pages 1089–1122, 1982.
- R. B. Myerson. Optimal auction design. Mathematics of operations research, 6(1):58–73, 1981.
- Bayesian meta-prior learning using empirical bayes. Management Science, 68(3):1737–1755, 2022.
- Econometrics for learning agents. In Proceedings of the Sixteenth ACM Conference on Economics and Computation, pages 1–18, 2015.
- Robust multi-agent counterfactual prediction. Advances in Neural Information Processing Systems, 32, 2019.
- O. Rafieian and H. Yoganarasimhan. Targeting and privacy in mobile advertising. Marketing Science, 40(2):193–218, 2021.
- Auction learning as a two-player game. In International Conference on Learning Representations, 2021. URL https://openreview.net/forum?id=YHdeAO61l6T.
- T. Roughgarden and J. R. Wang. Minimizing regret with multiple reserves. ACM Transactions on Economics and Computation (TEAC), 7(3):1–18, 2019.
- H. R. Varian. Online ad auctions. American Economic Review, 99(2):430–34, 2009.
- C. J. C. H. Watkins. Learning from delayed rewards. 1989.
- Online learning in repeated auctions. In Conference on Learning Theory, pages 1562–1583. PMLR, 2016.
- Budget constrained bidding by model-free reinforcement learning in display advertising. In Proceedings of the 27th ACM International Conference on Information and Knowledge Management, pages 1443–1451, 2018.
- R. Zeithammer. Soft floors in auctions. Management Science, 65(9):4204–4221, 2019.