TreeSearch at SemEval-2025 Task 8: Monte Carlo Tree Search for Question-Answering over Tabular Data

Aakarsh Nair, Huixin Yang


Abstract
Large Language Models (LLMs) can answer diverse questions but often generate factually incorrect responses. SemEval-2025 Task 8 focuses on table-based question-answering, providing 65 real-world tabular datasets and 1,300 questions that require precise filtering and summarization of underlying tables.We approach this problem as a neuro-symbolic code generation task, translating natural language queries into executable Python code to ensure contextually relevant and factually accurate answers. We formulate LLM decoding as a Markov Decision Process, enabling Monte Carlo Tree Search (MCTS) as a lookahead-based planning algorithm while decoding from the underlying code-generating LLM, instead of standard beam search.Execution success on synthetic tests and real datasets serves as a reward signal, allowing MCTS to explore multiple code-generation paths, validate outcomes, assign value to partial solutions, and refine code iteratively rather than merely maximizing sequence likelihood in a single step. Our approach improves accuracy by 2.38x compared to standard decoding.
Anthology ID:
2025.semeval-1.256
Volume:
Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Sara Rosenthal, Aiala Rosá, Debanjan Ghosh, Marcos Zampieri
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1974–1980
Language:
URL:
https://preview.aclanthology.org/corrections-2025-08/2025.semeval-1.256/
DOI:
Bibkey:
Cite (ACL):
Aakarsh Nair and Huixin Yang. 2025. TreeSearch at SemEval-2025 Task 8: Monte Carlo Tree Search for Question-Answering over Tabular Data. In Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025), pages 1974–1980, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
TreeSearch at SemEval-2025 Task 8: Monte Carlo Tree Search for Question-Answering over Tabular Data (Nair & Yang, SemEval 2025)
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PDF:
https://preview.aclanthology.org/corrections-2025-08/2025.semeval-1.256.pdf