ReHoPER: Receding-Horizon Planning for Enhanced Reasoning
Organizations: Department of Computer Science University of Illinois Chicago
Abstract
We propose ReHoPER, an inference-only, zero-shot method that improves large language models' reasoning by generating and answering intermediate questions along multiple paths before the final answer. It iteratively plans a horizon of candidate intermediate questions, selects one to answer, and replans from the updated history. ReHoPER is task-agnostic, using the same generic instructions across datasets and models without labeled data or task-specific prompt design. Across multiple datasets, including iLLC, a new controlled benchmark for compositional reasoning, ReHoPER outperforms strong baselines, with the largest gains in the most compositional settings. Our implementation and the iLLC generator are publicly available to support future work.
Figures & tables
| MuSR MM | MuSR OP | MuSR TA | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IO | CoT | PS | IO | CoT | PS | IO | CoT | PS | |||||||||||||||||||
| Model | SD | SC | RH | SC | RH | SC | RH | SD | SC | RH | SC | RH | SC | RH | SD | SC | RH | SC | RH | SC | RH | ||||||
| Gemma 3 | 57.6 | 54.4 | 61.2 | 61.2 | 62.0 | 61.6 | 65.6 | 50.0 | 50.4 | 55.1 | 51.6 | 55.5 | 54.7 | 55.9 | 50.0 | 58.8 | 47.6 | 56.0 | 51.2 | 58.0 | 56.0 | ||||||
| gpt-oss | 74.8 | 70.8 | 76.0 | 70.4 | 76.4 | 73.2 | 76.8 | 53.9 | 55.5 | 53.9 | 53.1 | 53.5 | 57.0 | 53.5 | 70.8 | 69.2 | 68.0 | 56.4 | 63.2 | 65.2 | 68.0 | ||||||
| Llama 3.1 8B | 54.0 | 56.8 | 62.4 | 56.4 | 60.8 | 57.2 | 63.6 | 44.5 | 49.2 | 53.1 | 52.0 | 48.4 | 52.0 | 48.4 | 34.8 | 35.2 | 43.6 | 43.2 | 47.6 | 45.2 | 47.6 | ||||||
| Llama 3.1 70B | 64.8 | 65.6 | 71.2 | 66.0 | 70.4 | 66.8 | 71.2 | 42.6 | 46.1 | 55.9 | 46.1 | 54.3 | 48.4 | 55.9 | 57.6 | 62.0 | 57.6 | 62.0 | 59.6 | 60.4 | 59.2 | ||||||
| MuSR MM | MoreHopQA | |||||||||||||||||||||||
| IO | CoT | PS | IO | CoT | PS | |||||||||||||||||||
| Model | -RP | -LA | RH | -RP | -LA | RH | -RP | -LA | RH | -RP | -LA | RH | -RP | -LA | RH | -RP | -LA | RH | ||||||
| Gemma 3 | 57.6 | 58.8 | 61.2 | 59.2 | 58.4 | 62.0 | 62.4 | 62.4 | 65.6 | 64.0 | 66.0 | 64.7 | 66.7 | 66.7 | 68.7 | 70.0 | 69.3 | 74.0 | ||||||
| gpt-oss | 72.4 | 70.0 | 76.0 | 72.0 | 68.0 | 76.4 | 74.0 | 71.2 | 76.8 | 80.7 | 78.7 | 78.7 | 79.3 | 79.3 | 80.0 | 80.7 | 78.7 | 81.3 | ||||||
| Llama 3.1 8B | 61.6 | 58.4 | 62.4 | 61.6 | 61.2 | 60.8 | 64.8 | 60.4 | 63.6 | 52.0 | 57.3 | 57.3 | 56.7 | 58.7 | 60.7 | 60.7 | 66.0 | 63.3 | ||||||
| Llama 3.1 70B | 70.4 | 70.0 | 71.2 | 72.0 | 72.4 | 70.4 | 71.6 | 71.2 | 71.2 | 68.7 | 74.0 | 71.3 | 70.7 | 72.7 | 71.3 | 72.7 | 74.0 | 74.0 | ||||||
| iLLC L1-4 | iLLC L1-6 | iLLC L2-4 | iLLC L2-6 | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model | SC 61 | SC 181 | RH | SC 61 | SC 181 | RH | SC 61 | SC 181 | RH | SC 61 | SC 181 | RH | |||||
| Llama 3.1 70B | Runtime | 1:16 | 3:37 | 2:42 | 1:26 | 4:23 | 4:12 | 2:11 | 6:23 | 7:56 | 2:37 | 9:04 | 11:15 | ||||
| Accuracy | 92.1 | 92.4 | 92.7 | 76.0 | 76.9 | 80.1 | 32.5 | 35.1 | 79.3 | 17.2 | 16.7 | 68.5 | |||||
| Mistral Small | Runtime | 0:38 | 1:38 | 0:54 | 0:43 | 2:03 | 0:55 | 0:48 | 2:08 | 1:15 | 0:56 | 2:41 | 1:13 | ||||
| Accuracy | 90.7 | 90.8 | 91.3 | 76.1 | 76.9 | 73.5 | 3.5 | 2.4 | 11.6 | 0.0 | 0.1 | 2.0 | |||||
| Phi-4 | Runtime | 0:45 | 1:46 | 1:06 | 0:52 | 2:31 | 1:57 | 0:50 | 2:01 | 1:18 | 1:00 | 2:55 | 2:21 | ||||
Appendix figures & tables25 assets
Supplementary material from the paper’s appendix.
Appendix
| MuSR | iLLC | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IO | CoT | PS | IO | CoT | PS | |||||||||||
| Model | SD | SC | RH | SC | RH | SC | RH | SD | SC | RH | SC | RH | SC | RH | ||
| Gemma 3 | 52.5 | 54.5 | 54.6 | 56.3 | 56.2 | 58.1 | 59.2 | 24.7 | 7.8 | 16.6 | 30.5 | 30.5 | 37.1 | 32.5 | ||
| gpt-oss | 66.5 | 65.2 | 66.0 | 60.0 | 64.4 | 65.1 | 66.1 | 62.2 | 85.9 | 83.9 | 78.3 | 83.4 | 52.7 | 83.9 | ||
| Llama 3.1 8B | 44.4 | 47.1 | 53.0 | 50.5 | 52.3 | 51.5 | 53.2 | 12.2 | 28.3 | 26.9 | 26.5 | 31.7 | 35.0 | 37.1 | ||
| Llama 3.1 70B | 55.0 | 57.9 | 61.6 | 58.0 | 61.4 | 58.5 | 62.1 | 39.9 | 40.3 | 69.9 | 44.5 | 69.9 | 56.6 | 77.3 | ||
| MuSR MM | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Model | #IQ | #IQ/Path std | #uniqIQ | #uniqIQ/Path std | %uniqIQ | %uniqIQ/Path | |||
| Gemma 3 | 60.00 | 59.29 | 98.82% | 100.00% | |||||
| gpt-oss | 39.38 | 39.29 | 99.77% | 100.00% | |||||
| Llama 3.1 8B | 59.95 | 59.54 | 99.32% | 100.00% | |||||
| Llama 3.1 70B | 60.00 | 56.72 | 94.53% | 100.00% | |||||
| Mistral Small | 59.96 | 55.86 | 93.16% | 100.00% | |||||
| iLLC L1-4 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Model | #IQ | #IQ/Path std | #uniqIQ | #uniqIQ/Path std | %uniqIQ | %uniqIQ/Path | |||
| Gemma 3 | 34.98 | 17.23 | 49.25% | 100.00% | |||||
| gpt-oss | 53.96 | 35.02 | 64.89% | 100.00% | |||||
| Llama 3.1 8B | 23.58 | 17.78 | 75.40% | 100.00% | |||||
| Llama 3.1 70B | 39.54 | 10.14 | 25.65% | 100.00% | |||||
| Mistral Small | 38.87 | 17.58 | 45.23% | 100.00% | |||||
| MuSR MM | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Model | #IQ | #IQ/Path std | #uniqIQ | #uniqIQ/Path std | %uniqIQ | %uniqIQ/Path | |||
| Gemma 3 | 48.73 | 8.12 1.07 | 48.53 | 8.12 1.07 | 99.58% | 100.00% | |||
| gpt-oss | 59.70 | 9.95 0.10 | 59.62 | 9.95 0.10 | 99.87% | 99.99% | |||
| Llama 3.1 8B | 46.69 | 7.78 2.42 | 46.64 | 7.78 2.42 | 99.90% | 99.97% | |||
| Llama 3.1 70B | 50.04 | 8.34 1.20 | 49.74 | 8.34 1.20 | 99.41% | 100.00% | |||
| Mistral Small | 58.78 | 9.80 0.38 | 58.12 | 9.79 0.39 | 98.87% | 99.94% | |||
| MuSR MM | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Model | #IQ | #IQ/Path std | #uniqIQ | #uniqIQ/Path std | %uniqIQ | %uniqIQ/Path | |||
| Gemma 3 | 60.00 | 10.00 0.00 | 58.76 | 9.95 0.09 | 97.93% | 99.53% | |||
| gpt-oss | 59.97 | 10.00 0.01 | 59.29 | 9.88 0.21 | 98.86% | 98.88% | |||
| Llama 3.1 8B | 60.00 | 10.00 0.00 | 57.86 | 9.69 0.47 | 96.43% | 96.87% | |||
| Llama 3.1 70B | 60.00 | 10.00 0.00 | 59.11 | 9.95 0.10 | 98.51% | 99.49% | |||
| Mistral Small | 60.00 | 10.00 0.00 | 57.53 | 9.62 0.52 | 95.88% | 96.15% | |||
| Gemma 3 | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MuSR MM (N: 250) | MoreHopQA (N: 150) | iLLC L2-4 (N: 250) | ||||||||||||||||
| Step | T std | %T/N std | R std | %R/T std | %R/N std | T std | %T/N std | R std | %R/T std | %R/N std | T std | %T/N std | R std | %R/T std | %R/N std | |||
| 1 2 | 250.00 0.00 | 100.0 0.0 | 249.83 0.37 | 99.9 0.1 | 99.9 0.1 | 138.17 2.27 | 92.1 1.5 | 122.50 3.69 | 88.7 3.0 | 81.7 2.5 | 250.00 0.00 | 100.0 0.0 | 209.33 21.02 | 83.7 8.4 | 83.7 8.4 | |||
| 2 3 | 250.00 0.00 | 100.0 0.0 | 250.00 0.00 | 100.0 0.0 | 100.0 0.0 | 124.33 2.49 | 82.9 1.7 | 105.50 2.14 | 84.9 2.6 | 70.3 1.4 | 250.00 0.00 | 100.0 0.0 | 131.00 34.24 | 52.4 13.7 | 52.4 13.7 | |||
| 3 4 | 250.00 0.00 | 100.0 0.0 | 249.83 0.37 | 99.9 0.1 | 99.9 0.1 | 118.17 3.13 | 78.8 2.1 | 101.33 3.68 | 85.8 2.0 | 67.6 2.5 | 248.17 1.21 | 99.3 0.5 | 73.83 16.87 | 29.7 6.8 | 29.5 6.7 | |||
| 4 5 | 250.00 0.00 | 100.0 0.0 | 250.00 0.00 | 100.0 0.0 | 100.0 0.0 | 106.00 5.32 | 70.7 3.5 | 90.50 3.91 | 85.4 2.3 | 60.3 2.6 | 241.17 7.60 | 96.5 3.0 | 74.83 18.96 | 31.1 8.0 | 29.9 7.6 | |||
| Llama 3.1 8B | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MuSR MM (N: 250) | MoreHopQA (N: 150) | iLLC L2-4 (N: 250) | ||||||||||||||||
| Step | T std | %T/N std | R std | %R/T std | %R/N std | T std | %T/N std | R std | %R/T std | %R/N std | T std | %T/N std | R std | %R/T std | %R/N std | |||
| 1 2 | 250.00 0.00 | 100.0 0.0 | 250.00 0.00 | 100.0 0.0 | 100.0 0.0 | 109.67 5.12 | 73.1 3.4 | 101.83 4.52 | 92.9 1.4 | 67.9 3.0 | 221.83 8.63 | 88.7 3.5 | 219.17 9.10 | 98.8 1.0 | 87.7 3.6 | |||
| 2 3 | 250.00 0.00 | 100.0 0.0 | 249.00 1.00 | 99.6 0.4 | 99.6 0.4 | 105.67 4.15 | 70.4 2.8 | 99.00 6.14 | 93.6 2.8 | 66.0 4.1 | 210.33 9.62 | 84.1 3.8 | 199.00 9.27 | 94.6 2.3 | 79.6 3.7 | |||
| 3 4 | 249.67 0.47 | 99.9 0.2 | 248.83 0.90 | 99.7 0.3 | 99.5 0.4 | 94.67 2.49 | 63.1 1.7 | 88.67 2.21 | 93.7 2.3 | 59.1 1.5 | 201.83 11.91 | 80.7 4.8 | 186.50 9.39 | 92.5 1.0 | 74.6 3.8 | |||
| 4 5 | 250.00 0.00 | 100.0 0.0 | 249.00 0.82 | 99.6 0.3 | 99.6 0.3 | 79.67 2.29 | 53.1 1.5 | 74.17 2.91 | 93.1 1.7 | 49.4 1.9 | 176.50 13.46 | 70.6 5.4 | 154.50 13.51 | 87.5 1.9 | 61.8 5.4 | |||
| iLLC L2-4 (Development Set) | MoreHopQA | |||||||||||||||||||||||||||||
| IO | CoT | PS | IO | CoT | PS | |||||||||||||||||||||||||
| Model | T=.2 | T=.3 | T=.5 | T=.7 | T=.2 | T=.3 | T=.5 | T=.7 | T=.2 | T=.3 | T=.5 | T=.7 | T=.2 | T=.3 | T=.5 | T=.7 | T=.2 | T=.3 | T=.5 | T=.7 | T=.2 | T=.3 | T=.5 | T=.7 | ||||||
| Gemma 3 | 6.8 | 6.8 | 5.6 | 7.6 | 5.6 | 7.6 | 5.6 | 8.4 | 4.0 | 4.8 | 6.0 | 6.8 | 64.7 | 67.3 | 64.0 | 66.0 | 66.0 | 66.0 | 66.7 | 67.3 | 70.7 | 71.3 | 74.7 | 73.3 | ||||||
| gpt-oss | 90.8 | 92.4 | 93.2 | 94.8 | 89.2 | 92.0 | 93.6 | 94.8 | 89.6 | 92.8 | 91.2 | 93.6 | 78.7 | 78.7 | 81.3 | 80.0 | 78.0 | 79.3 | 80.0 | 80.0 | 80.0 | 80.7 | 82.0 | 79.3 | ||||||
| Llama 3.1 8B | 10.8 | 8.8 | 16.8 | 20.0 | 16.4 | 12.4 | 18.4 | 11.2 | 40.4 | 30.0 | 38.4 | 42.4 | 57.3 | 58.7 | 56.7 | 55.3 | 56.0 | 57.3 | 58.0 | 62.0 | 58.7 | 60.7 | 63.3 | 64.7 | ||||||
| Mistral Small | 8.0 | 7.2 | 9.2 | 7.2 | 5.6 | 8.8 | 9.2 | 6.0 | 8.8 | 8.4 | 8.4 | 6.4 | 66.0 | 70.7 | 71.3 | 70.0 | 67.3 | 68.0 | 67.3 | 72.0 | 70.7 | 70.7 | 70.7 | 68.0 | ||||||
| iLLC L2-4 (Development Set) | MoreHopQA | |||||||||||||||||||||||||||||
| IO | CoT | PS | IO | CoT | PS | |||||||||||||||||||||||||
| Model | 5-12 | 6-10 | 10-6 | 12-5 | 5-12 | 6-10 | 10-6 | 12-5 | 5-12 | 6-10 | 10-6 | 12-5 | 5-12 | 6-10 | 10-6 | 12-5 | 5-12 | 6-10 | 10-6 | 12-5 | 5-12 | 6-10 | 10-6 | 12-5 | ||||||
| Gemma 3 | 6.0 | 6.8 | 5.6 | 4.8 | 8.0 | 8.0 | 5.6 | 5.6 | 6.4 | 7.6 | 6.0 | 5.6 | 66.0 | 64.7 | 64.0 | 62.7 | 66.7 | 64.7 | 66.7 | 64.0 | 74.0 | 74.7 | 74.7 | 74.0 | ||||||
| gpt-oss | 94.0 | 94.4 | 93.2 | 94.8 | 93.6 | 93.6 | 93.6 | 93.6 | 93.2 | 94.4 | 91.2 | 92.8 | 78.0 | 78.0 | 81.3 | 80.0 | 78.0 | 81.3 | 80.0 | 79.3 | 79.3 | 82.0 | 82.0 | 78.7 | ||||||
| Llama 3.1 8B | 23.6 | 21.2 | 16.8 | 10.8 | 19.6 | 20.8 | 18.4 | 16.0 | 38.4 | 40.0 | 38.4 | 33.6 | 54.7 | 56.0 | 56.7 | 54.7 | 60.7 | 59.3 | 58.0 | 56.0 | 65.3 | 63.3 | 63.3 | 61.3 | ||||||
| Mistral Small | 10.0 | 10.0 | 9.2 | 5.6 | 12.8 | 12.8 | 9.2 | 8.0 | 11.2 | 9.6 | 8.4 | 6.4 | 70.7 | 71.3 | 71.3 | 72.0 | 67.3 | 67.3 | 67.3 | 67.3 | 71.3 | 70.7 | 70.7 | 71.3 | ||||||
| MoreHopQA | iLLC L2-4 | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IO | CoT | PS | IO | CoT | PS | |||||||||
| Model | SC | RH | SC | RH | SC | RH | SC | RH | SC | RH | SC | RH | ||
| Gemma 3 | 61.8 0.4 | 65.8 1.0 | 64.7 0.7 | 68.7 0.0 | 66.7 0.7 | 74.7 1.2 | 7.3 0.2 | 6.9 1.3 | 7.6 0.0 | 6.9 0.9 | 3.6 0.8 | 8.1 1.7 | ||
| Llama 3.1 8B | 60.7 1.2 | 57.1 1.7 | 60.0 0.7 | 60.0 1.8 | 62.4 1.5 | 63.1 0.4 | 11.9 0.8 | 17.5 4.1 | 12.5 3.2 | 18.4 2.0 | 30.4 1.1 | 41.6 1.4 | ||
| Mistral Small | 70.2 0.4 | 71.3 0.0 | 69.1 1.0 | 68.7 1.2 | 72.2 0.4 | 71.1 1.4 | 1.9 0.5 | 10.5 0.6 | 2.4 0.4 | 9.6 1.7 | 3.1 0.8 | 10.8 1.2 | ||
| Phi-4 | 77.3 0.7 | 76.0 1.8 | 76.4 0.4 | 80.4 1.0 | 77.6 0.4 | 78.4 1.7 | 13.2 0.4 | 54.3 0.8 | 10.0 0.4 | 62.0 1.7 | 9.7 0.8 | 62.7 1.3 | ||
| iLLC L1-8 | iLLC L2-8 | |||||||||||||||||
| IO | CoT | PS | IO | CoT | PS | |||||||||||||
| Model | SD | SC | RH | SC | RH | SC | RH | SD | SC | RH | SC | RH | SC | RH | ||||
| Gemma 3 | 26.4 | 7.6 | 12.4 | 36.0 | 28.8 | 52.8 | 32.8 | 0.0 | 0.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | ||||
| gpt-oss | 58.8 | 84.0 | 76.4 | 78.4 | 74.8 | 77.6 | 76.0 | 45.6 | 76.4 | 80.0 | 61.6 | 80.8 | 6.0 | 81.2 | ||||
| Llama 3.1 8B | 7.6 | 31.2 | 27.6 | 24.0 | 39.2 | 39.2 | 34.4 | 0.0 | 0.8 | 2.0 | 0.0 | 4.0 | 0.4 | 2.4 | ||||
| Llama 3.1 70B | 56.0 | 59.2 | 62.8 | 48.8 | 63.2 | 68.8 | 70.4 | 0.8 | 1.2 | 44.0 | 3.6 | 46.4 | 12.8 | 54.0 | ||||
| Model (as used) | Org / Family | Params | Context |
|---|---|---|---|
| google/gemma-3-12b-it | Google / Gemma 3 | 12B | 128K |
| openai/gpt-oss-20b | OpenAI / gpt-oss | 21B (3.6B active) | 128K |
| meta-llama/Llama-3.1-8B-Instruct | Meta / Llama 3.1 | 8B | 128K |
| hugging-quants/Meta-Llama-3.1-70B-Instruct-AWQ-INT4 | Meta / Llama 3.1 | 70B | 128K |
| stelterlab/Mistral-Small-24B-Instruct-2501-AWQ | Mistral / Mistral Small 3 | 24B | 32K |
| microsoft/phi-4 | Microsoft / Phi | 14B | 16K |
| Dataset | Task | Test Set Size | Answer Format |
|---|---|---|---|
| Per Task | |||
| MuSR | Murder Mysteries, Team Allocation | 250 | Choice number |
| Object Placement | 256 | ||
| MoreHopQA | - | 150 | Short text answer |
| iLLC | L1-4, L1-6, L1-8, L2-4, L2-6, L2-8 | 250 | Concatenated letters |