Uncovering Latent Topics with TopicGPT: A Novel Framework for Interpretable Topic Modeling
Topic modeling, a technique used to uncover the underlying thematic structure in large text corpora, has long been limited by traditional methods such as Latent Dirichlet Allocation (LDA). These methods often generate topics that are incoherent and difficult to interpret, hindering their practical application in content analysis and other fields requiring clear thematic categorization.
However, a new framework, TopicGPT, is revolutionizing the field of topic modeling by leveraging large language models (LLMs) to generate and refine topics in a corpus. This novel approach produces topics that are more in line with human categorizations, providing natural language labels and descriptions for topics, and allowing for customization without the need for model retraining.
The Limitations of Traditional Topic Modeling Methods
Traditional topic modeling methods, such as LDA, SeededLDA, and BERTopic, have been widely used for exploring latent thematic structures in text collections. However, these models often fail to produce high-quality and easily interpretable topics. LDA, for instance, represents topics as distributions over words, which can result in incoherent and difficult-to-interpret topics. SeededLDA attempts to guide the topic generation process with user-defined seed words, while BERTopic uses contextualized embeddings for topic extraction.
The TopicGPT Framework
TopicGPT operates in two main stages: topic generation and topic assignment. In the topic generation stage, the framework iteratively prompts an LLM to generate topics based on a sample of documents from the input dataset and a list of previously generated topics. This process encourages the creation of distinctive and specific topics. The generated topics are then refined to remove redundant and infrequent topics, ensuring a coherent and comprehensive set.
In the topic assignment stage, the LLM assigns topics to new documents by providing a quotation from the document that supports its assignment, enhancing the verifiability of the topics. This method has been shown to produce higher-quality topics compared to traditional methods, achieving a harmonic mean purity of 0.74 against human-annotated Wikipedia topics, compared to 0.64 for the strongest baseline.
Topic modeling with TopicGPT
Evaluating TopicGPT’s Performance
The framework’s performance was evaluated on two datasets: Wikipedia articles and Congressional bills. The results demonstrated that TopicGPT’s topics and assignments align more closely with human-annotated ground truth topics than those generated by LDA, SeededLDA, and BERTopic. The researchers measured topical alignment using external clustering metrics such as harmonic mean purity, normalized mutual information, and the adjusted Rand index, finding substantial improvements over baseline methods.
The Future of Topic Modeling
TopicGPT, a groundbreaking advancement in topic modeling, not only overcomes the limitations of traditional methods but also offers practical benefits. By using a prompt-based framework and the combined power of GPT-4 and GPT-3.5-turbo, TopicGPT generates coherent, human-aligned topics that are both interpretable and customizable. This versatility makes it a valuable tool for a wide range of applications in content analysis and beyond, promising to revolutionize the field of topic modeling.
TopicGPT framework
