mlsanityData to 7 Oct 2026

Implementation Matters in Deep Policy Gradients: A Case Study on PPO and TRPO

arXiv 2005.12729 ↗First posted 25 May 2020cs.LG cs.RO stat.MLcited by 184

Not on the map. Why?

Cited by 54 in LLM alignment / RLHF / preference optimisation, but placed by its own abstract, which didn’t fit.

Abstract (arXiv)

We study the roots of algorithmic progress in deep policy gradient algorithms through a case study on two popular algorithms: Proximal Policy Optimization (PPO) and Trust Region Policy Optimization (TRPO). Specifically, we investigate the consequences of "code-level optimizations:" algorithm augmentations found only in implementations or described as auxiliary details to the core algorithm. Seemingly of secondary importance, such optimizations turn out to have a major impact on agent behavior. Our results show that they (a) are responsible for most of PPO's gain in cumulative reward over TRPO, and (b) fundamentally change how RL methods function. These insights show the difficulty and importance of attributing performance gains in deep reinforcement learning. Code for reproducing our results is available at https://github.com/MadryLab/implementation-matters .

Key facts. Cited by 184 papers in the map (data through 7 Oct 2026). First posted on arXiv 25 May 2020.

Builds on

No reference list yet.

Built on by

Cited by year (2026 to 7 Oct)

Citing papers per year: 2020: 1; 2021: 17; 2022: 16; 2023: 30; 2024: 42; 2025: 37; 2026: 41.

184 papers.

Sort:

By area:

  1. 2023RAFT: Reward rAnked FineTuning for Generative Foundation Model Alignmentcited by 672
  2. 2024Interpretable Preferences via Multi-Objective Reward Modeling and Mixture-of-Expertscited by 369
  3. 2023Iterative Preference Learning from Human Feedback: Bridging Theory and Practice for RLHF under KL-Constraintcited by 346
  4. 2024RLHF Workflow: From Reward Modeling to Online RLHFcited by 265
  5. 2023Detecting and Preventing Hallucinations in Large Vision Language Modelscited by 254
  6. 2024From r to Q^*: Your Language Model is Secretly a Q-Functioncited by 242
  7. 2023Secrets of RLHF in Large Language Models Part I: PPOcited by 226
  8. 2023ReMax: A Simple, Effective, and Efficient Reinforcement Learning Method for Aligning Large Language Modelscited by 184
  9. 2023Mitigating the Alignment Tax of RLHFcited by 181
  10. 2024Arithmetic Control of LLMs for Diverse User Preferences: Directional Preference Alignment with Multi-Objective Rewardscited by 145
  11. 2021Robust Reinforcement Learning on State Observations with Learned Optimal Adversarycited by 133
  12. 2024ODIN: Disentangled Reward Mitigates Hacking in RLHFcited by 133
38 more
  1. 2024DPO Meets PPO: Reinforced Token Optimization for RLHFcited by 126
  2. 2023Revisiting the Minimalist Approach to Offline Reinforcement Learningcited by 121
  3. 2023Structured State Space Models for In-Context Reinforcement Learningcited by 109
  4. 2024Provably Mitigating Overoptimization in RLHF: Your SFT Loss is Implicitly an Adversarial Regularizercited by 109
  5. 2021Learning to Iteratively Solve Routing Problems with Dual-Aspect Collaborative Transformercited by 108
  6. 2024Back to Basics: Revisiting REINFORCE Style Optimization for Learning from Human Feedback in LLMscited by 103
  7. 2025Audio-Reasoner: Improving Reasoning Capability in Large Audio Language Modelscited by 94
  8. 2025Fin-R1: A Large Language Model for Financial Reasoning through Reinforcement Learningcited by 82
  9. 2024RRM: Robust Reward Model Training Mitigates Reward Hackingcited by 75
  10. 2024Simplifying Deep Temporal Difference Learningcited by 71
  11. 2024Towards Analyzing and Understanding the Limitations of DPO: A Theoretical Perspectivecited by 69
  12. 2021Rethinking the Implementation Tricks and Monotonicity Constraint in Cooperative Multi-Agent Reinforcement Learningcited by 68
  13. 2024REBEL: Reinforcement Learning via Regressing Relative Rewardscited by 66
  14. 2024Building Math Agents with Multi-Turn Iterative Preference Learningcited by 66
  15. 2023LMFlow: An Extensible Toolkit for Finetuning and Inference of Large Foundation Modelscited by 58
  16. 2023Pairwise Proximal Policy Optimization: Harnessing Relative Feedback for LLM Alignmentcited by 57
  17. 2025Part I: Tricks or Traps? A Deep Dive into RL for LLM Reasoningcited by 53
  18. 2024Cal-DPO: Calibrated Direct Preference Optimization for Language Model Alignmentcited by 50
  19. 2022Towards a Standardised Performance Evaluation Protocol for Cooperative MARLcited by 48
  20. 2024From Lists to Emojis: How Format Bias Affects Model Alignmentcited by 48
  21. 2023Efficient RLHF: Reducing the Memory Usage of PPOcited by 40
  22. 2024Alignment of Diffusion Models: Fundamentals, Challenges, and Futurecited by 34
  23. 2022Mirror Learning: A Unifying Framework of Policy Optimisationcited by 31
  24. 2025SimPER: A Minimalist Approach to Preference Alignment without Hyperparameterscited by 25
  25. 2021Differentiable Trust Region Layers for Deep Reinforcement Learningcited by 24
  26. 2024Streaming Deep Reinforcement Learning Finally Workscited by 24
  27. 2024Plasticity Loss in Deep Reinforcement Learning: A Surveycited by 24
  28. 2024On the consistency of hyper-parameter selection in value-based deep reinforcement learningcited by 21
  29. 2024Mission Impossible: A Statistical Perspective on Jailbreaking LLMscited by 21
  30. 2021Towards Deeper Deep Reinforcement Learning with Spectral Normalizationcited by 19
  31. 2022You May Not Need Ratio Clipping in PPOcited by 19
  32. 2022Deep Black-Box Reinforcement Learning with Movement Primitivescited by 18
  33. 2021Hyperparameter Selection for Imitation Learningcited by 17
  34. 2025XQC: Well-conditioned Optimization Accelerates Deep Reinforcement Learningcited by 17
  35. 2022Policy-Based Bayesian Experimental Design for Non-Differentiable Implicit Modelscited by 15
  36. 2025A Survey on Progress in LLM Alignment from the Perspective of Reward Designcited by 15
  37. 2024Acquiring Diverse Skills using Curriculum Reinforcement Learning with Mixture of Expertscited by 14
  38. 2024If CLIP Could Talk: Understanding Vision-Language Model Representations Through Their Preferred Concept Descriptionscited by 14

50 most cited of 184 All 184 (JSON)