CounterBench: A Benchmark for Counterfactuals Reasoning in Large Language Models
Yuefei Chen, Vivek K. Singh, Jing Ma, Ruxiang Tang
TL;DR
CounterBench introduces a formal, causality-grounded benchmark of 1K counterfactual questions to evaluate LLMs beyond commonsense reasoning. The authors show that contemporary LLMs struggle with counterfactual inference, even with prompting strategies like CausalCoT. They propose CoIn, a two-phase reasoning framework with iterative search and backtracking, achieving substantial gains and demonstrating strong generalization on the CLADDER dataset. The work provides a rigorous benchmark and a robust reasoning paradigm that can enhance causal reasoning in LLMs, with potential impact on domains requiring robust counterfactual analysis.
Abstract
Counterfactual reasoning is widely recognized as one of the most challenging and intricate aspects of causality in artificial intelligence. In this paper, we evaluate the performance of large language models (LLMs) in counterfactual reasoning. In contrast to previous studies that primarily focus on commonsense causal reasoning, where LLMs often rely on prior knowledge for inference, we specifically assess their ability to perform counterfactual inference using a set of formal rules. To support this evaluation, we introduce a new benchmark dataset, CounterBench, comprising 1K counterfactual reasoning questions. The dataset is designed with varying levels of difficulty, diverse causal graph structures, distinct types of counterfactual questions, and multiple nonsensical name variants. Our experiments demonstrate that counterfactual reasoning poses a significant challenge for LLMs, with most models performing at levels comparable to random guessing. To enhance LLM's counterfactual reasoning ability, we propose a novel reasoning paradigm, CoIn, which guides LLMs through iterative reasoning and backtracking to systematically explore counterfactual solutions. Experimental results show that our method significantly improves LLM performance on counterfactual reasoning tasks and consistently enhances performance across different LLMs.Our dataset is available at https://huggingface.co/datasets/CounterBench/CounterBench.
