Taming the Monster: A Fast and Simple Algorithm for Contextual Bandits
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Abstract (arXiv)
We present a new algorithm for the contextual bandit learning problem, where the learner repeatedly takes one of K actions in response to the observed context, and observes the reward only for that chosen action. Our method assumes access to an oracle for solving fully supervised cost-sensitive classification problems and achieves the statistically optimal regret guarantee with only tildeO(√KT/log N) oracle calls across all T rounds, where N is the number of policies in the policy class we compete against. By doing so, we obtain the most practical contextual bandit learning algorithm amongst approaches that work for general policy classes. We further conduct a proof-of-concept experiment which demonstrates the excellent computational and prediction performance of (an online variant of) our algorithm relative to several baselines.
Key facts. Cited by 200 papers in the map (data through 7 Oct 2026). First posted on arXiv 4 Feb 2014.
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Citing papers per year: 2019: 1; 2020: 0; 2021: 36; 2022: 42; 2023: 40; 2024: 31; 2025: 23; 2026: 27.
200 papers.
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- 2021Adapting to Misspecification in Contextual Banditscited by 81
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- 2021Cautiously Optimistic Policy Optimization and Exploration with Linear Function Approximationcited by 53
- 2021Efficient First-Order Contextual Bandits: Prediction, Allocation, and Triangular Discriminationcited by 53
- 2021Achieving Near Instance-Optimality and Minimax-Optimality in Stochastic and Adversarial Linear Bandits Simultaneouslycited by 48
- 2021Distributionally Robust Learningcited by 44
- 2021Efficient and Optimal Algorithms for Contextual Dueling Bandits under Realizabilitycited by 44
38 more
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50 most cited of 200 All 200 (JSON)
- 2026Oracle-Efficient Online Classification with Stochastic Inputs and Adversarial Outputs27 Sep 2026
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50 newest of 200 All 200 (JSON)
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- 2023Importance-Weighted Offline Learning Done Rightcited by 15
- 2023Oracle-Efficient Pessimism: Offline Policy Optimization in Contextual Banditscited by 14
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- 2022On Efficient Online Imitation Learning via Classification26 Sep 2022
- 2021Offline Neural Contextual Bandits: Pessimism, Optimization and Generalization27 Nov 2021
- 2021Representation Learning for Online and Offline RL in Low-rank MDPs9 Oct 2021
- 2019Provably Efficient Imitation Learning from Observation Alone27 May 2019
- 2024Self-Improvement in Language Models: The Sharpening Mechanismcited by 102
- 2021Bellman Eluder Dimension: New Rich Classes of RL Problems, and Sample-Efficient Algorithmscited by 222
- 2021Non-stationary Reinforcement Learning without Prior Knowledge: An Optimal Black-box Approachcited by 98
- 2021Adapting to Misspecification in Contextual Banditscited by 81
- 2021Cautiously Optimistic Policy Optimization and Exploration with Linear Function Approximationcited by 53
- 2021Efficient First-Order Contextual Bandits: Prediction, Allocation, and Triangular Discriminationcited by 53
- 2021Achieving Near Instance-Optimality and Minimax-Optimality in Stochastic and Adversarial Linear Bandits Simultaneouslycited by 48
- 2021Distributionally Robust Learningcited by 44
- 2021Efficient and Optimal Algorithms for Contextual Dueling Bandits under Realizabilitycited by 44
- 2021Provable Model-based Nonlinear Bandit and Reinforcement Learning: Shelve Optimism, Embrace Virtual Curvaturecited by 32
- 2022Contextual Bandits with Large Action Spaces: Made Practicalcited by 32
- 2022Making Decisions under Outcome Performativitycited by 32
- 2022A General Framework for Sample-Efficient Function Approximation in Reinforcement Learningcited by 31
12 most cited of 181 All 181 (JSON)
- 2026Oracle-Efficient Online Classification with Stochastic Inputs and Adversarial Outputs27 Sep 2026
- 2026Nearly Minimax-Optimal Regret for Linear Contextual Bandits with Arbitrary Adaptive Action Sets14 Sep 2026
- 2026When Greedy Sampling Explores: KL-Regularized Contextual Bandits without Eluder-Dimension Dependence11 Sep 2026
- 2026CAROL: Context-Aware Online Learning for Fuzzer Scheduling6 Sep 2026
- 2026Designing for the Next Click: Bandits for Real-Time Page Layout30 Aug 2026
- 2026Optimizing What Policies Learn From: Recoverability-aware Rollout Intervention Learning5 Aug 2026
- 2026Optimal and Efficient Contextual Combinatorial Semi-bandits with General Function Approximation15 Jul 2026
- 2026Policy Regret for Embedding Model Routing: Contextual Bandits with Low-Rank Experts12 Jun 2026
- 2026Belief-Space Control for Personalized Cancer Treatment via Active Inference9 Jun 2026
- 2026Online KL-Regularized Reinforcement Learning with Function Approximation under Misspecification4 Jun 2026
- 2026The Sample Complexity of Multiclass and Sparse Contextual Bandits28 May 2026
- 2026PAC Learning with Bandit Feedback: Sharp Sample Complexity in the Realizable Setting25 May 2026
12 newest of 181 All 181 (JSON)