SampleLLM: Optimizing Tabular Data Synthesis in Recommendations

TL;DR

SampleLLM is a two-stage framework that improves tabular data synthesis for recommendations by aligning generated data distribution with real data and refining feature relationships, leveraging LLMs and importance sampling.

Contribution

It introduces a novel two-stage approach combining LLMs with distribution alignment and feature importance sampling for enhanced tabular data synthesis in recommender systems.

Findings

Significantly outperforms existing methods on recommendation datasets.

Improves distribution alignment and feature relationship modeling.

Demonstrates effectiveness in online deployment.

Abstract

Tabular data synthesis is crucial in machine learning, yet existing general methods-primarily based on statistical or deep learning models-are highly data-dependent and often fall short in recommender systems. This limitation arises from their difficulty in capturing complex distributions and understanding feature relationships from sparse and limited data, along with their inability to grasp semantic feature relations. Recently, Large Language Models (LLMs) have shown potential in generating synthetic data samples through few-shot learning and semantic understanding. However, they often suffer from inconsistent distribution and lack of diversity due to their inherent distribution disparity with the target dataset. To address these challenges and enhance tabular data synthesis for recommendation tasks, we propose a novel two-stage framework named SampleLLM to improve the quality of LLM-based tabular data synthesis for recommendations by ensuring better distribution alignment. In the first stage, SampleLLM employs LLMs with Chain-of-Thought prompts and diverse exemplars to generate data that closely aligns with the target dataset distribution, even when input samples are limited. The second stage uses an advanced feature attribution-based importance sampling method to refine feature relationships within the synthesized data, reducing any distribution biases introduced by the LLM. Experimental results on three recommendation datasets, two general datasets, and online deployment illustrate that SampleLLM significantly surpasses existing methods for recommendation tasks and holds promise for a broader range of tabular data scenarios.