The Property Graph Index is a modular component of LlamaIndex that allows for customizable graph construction and retrieval. It uses a property graph data structure, where nodes have labels and optional node properties. The index is designed to be flexible and adaptable, with various graph constructors and retrievers available. In this blog post, the authors explore how to implement entity deduplication and design custom retrieval methods to enhance GraphRAG accuracy. They demonstrate how to construct a knowledge graph using schema-guided extraction, perform entity deduplication using text embedding similarity and word distance, and implement a custom retriever that uses entity detection and vector context retrieval. The authors also discuss the importance of entity disambiguation and provide guidance on how to customize the retriever for specific use cases. Overall, the Property Graph Index offers a powerful toolkit for building knowledge graphs and improving graph-related accuracy.