Research map / Reinforcement learning / Visual and representation RL
Explaining RL Decisions with Trajectories': A Reproducibility Study
Read the paperCheck your idea against 108,967 papers
AI-extracted summary. Written by AI from the paper's full text. Numbers and claims can be wrong or missing context, so check the paper before you cite or build on it.
A reproducibility study of the trajectory-attribution XRL method ("Explaining RL decisions with trajectories"), partially confirming its claims on Grid-World and extending experiments to Seaquest, HalfCheetah, Breakout and Q*Bert.
Problem
Whether the claims of an offline RL explainability method that attributes agent decisions to clusters of training trajectories hold up under independent reproduction across environments.
Approach
Re-implements the trajectory-attribution pipeline (trajectory encoding, XMeans clustering, complementary datasets retraining policies, attribution frequency) for Grid-World, partially from authors' code and from scratch for other environments, then tests four claims with extra metrics, DBSCAN clustering, and alternative encoders.
Key results
- On Grid-World the original policy achieves the highest ISV (0.307), and the mean-cluster ISV (0.3029 reproduced vs 0.3027 original) closely matches the original paper.
- Seaquest reproduction differed substantially from the original paper's numbers, and only one of three high-level Seaquest behaviours was identified.
- Human study with 20 participants gave ~72.5% correct identification of one attributed trajectory and ~63% identifying all attributed trajectories, but the authors judged the evidence insufficient to confirm the claim.
Measured effects reported in the paper
| What was changed | Where | Measured | Effect |
|---|---|---|---|
| train on all trajectories rather than excluding a cluster | trajectory-attribution policies · Grid-World | ISV: 0.287 ± 5e-03 -> 0.307 ± 2e-04 | Helped |
| train on all trajectories rather than excluding a cluster | trajectory-attribution policies · Seaquest | ISV: 2.010 ± 4e-02 -> 3.569 ± 1e-04 | Helped |
| train on all trajectories rather than excluding a cluster | trajectory-attribution policies · HalfCheetah | ISV: 3.3615 -> 3.5280 | Hurt |
| train on all trajectories rather than excluding a cluster | trajectory-attribution policies · Q*Bert | ISV: 1.075 -> 1.118 | Hurt |
| train on all trajectories rather than excluding a cluster | trajectory-attribution policies · Breakout | ISV: 0.764 -> 0.812 | Helped |
| add cluster 5 trajectories to training (ablation) | HalfCheetah trajectory-attribution policy · HalfCheetah | ISV: 3.5280 -> 3.3615 | Hurt |
| add cluster 1 trajectories to training (ablation) | Q*Bert trajectory-attribution policy · Q*Bert | ISV: 1.118 -> 1.075 | Hurt |
| replace XMeans with DBSCAN (ablation) | Grid-World trajectory clustering · Grid-World | ISV: 0.3059 | No clear effect |
| replace the LSTM encoder with a Trajectory Transformer (ablation) | Grid-World trajectory encoding · Grid-World | ISV: 0.3451 -> 0.3413 | Hurt |
| replace the LSTM encoder with BERT (ablation) | Grid-World trajectory encoding · Grid-World | ISV: 0.3451 -> 0.3427 | Hurt |
| use 250 trajectories instead of 60 (ablation) | Grid-World clustering · Grid-World | presence of the same-length trajectory pattern | Hurt |
| use DBSCAN instead of XMeans (ablation) | Grid-World clustering · Grid-World | visual cluster overlap | Helped |
Surprising findings
- Q*Bert highest ISV assigned to cluster 1, contradicting the claim that removing trajectories lowers ISV.
- Grid-World XMeans attribution yields no state explained solely by trajectories passing through it, with most attributed trajectories far from the state.
Limitations
- Original code only partially available (Grid-World); other environments implemented from scratch with unknown hyperparameters.
- Human study limited to 20 participants and Grid-World only.
- Only one cluster allowed per attribution, which the authors note as a limitation of the original method.
Experimental setup
Datasets: d4rl-Atari Seaquest Expert-offline RL Breakout and Q*Bert D4RL HalfCheetah Grid-World (generated with Dyna-Q)
Benchmarks: Grid-World 7x7 Grid-World Four Room 11x11 Seaquest HalfCheetah Breakout Q*Bert
Metrics: initial state value local mean absolute action-value difference action contrast measure Wasserstein distance cluster attribution frequency average distance of attributed trajectories
Baselines: DBSCAN BERT
Builds on: Explaining RL decisions with trajectories Dyna-Q XMeans DBSCAN SAC Decision Transformer
Closest papers by meaning
- Offline Preference-Based Trajectory Evaluation (NeurIPS 2026 · similarity 0.82)
- Decision Information Meets Large Language Models: The Future of Explainable Operations Research (ICLR 2025 · similarity 0.81)
- RL Squeezes, SFT Expands: A Comparative Study of Reasoning LLMs (ICLR 2026 · similarity 0.81)
- Think Twice, Act Once: A Co-Evolution Framework of LLM and RL for Large-Scale Decision Making (ICML 2025 · similarity 0.80)
- LARK: Learnability-Grounded Trajectory Selection for Efficient Reasoning Distillation (NeurIPS 2026 · similarity 0.80)
- Thought Branches: Interpreting LLM Reasoning Requires Resampling (ICLR 2026 · similarity 0.80)
Writing a paper in this area? scime draft is a free LaTeX editor with AI included, real-time co-authors and a check of your references and venue rules before you submit. It also imports OpenAI Prism projects.
