Data Augmentation for Fake Review Detection Based on Large Language Model with Multi-stage Prompting
摘要
Fake reviews on e-commerce platforms mislead consumer decisions, damage merchant reputations, and undermine market order. Detecting fake review has become vital for protecting customer rights and maintaining platform fairness. Existing fake review datasets often suffer from severe class imbalance, which degrades the performance of detection model. To address this issue, we propose a data augmentation method based on Large Language Models with Multi-Stage Prompting (LLM-MSP) for fake review detection. First, the original reviews are parsed by LLMs to extract key elements such as review targets, detailed descriptions, and sentiment tendencies, and converted into structured data. Second, prompts are then constructed based on the extracted structures to guide LLMs to generate natural and semantically coherent reviews, and the high-quality generated reviews are selected to augment the original dataset. Finally, different classification models based on BERT are adopted to test the effectiveness of LLM-MSP for fake review detection. Experimental results show that, compared with the single-stage prompting, LLM-MSP improves the novelty and diversity of the generated fake reviews. Furthermore, among various data augmentation methods, LLM-MSP achieved the best classification performance. Specifically, compared with the original imbalanced dataset, the classification accuracy increased about 10% by incorporating the data generated by LLM-MSP. These findings validate the effectiveness and practical value of LLM-MSP for data augmentation task of fake review detection.