RAG Series: GraphRAG

By 
Axel Sjöberg
December 19, 2024

Introduction to RAG

Retrieval-Augmented Generation (RAG) has emerged as a transformative framework in the AI landscape, combining the generative capabilities of large language models (LLMs) with the precision of retrieval mechanisms. By linking LLMs to external knowledge sources, RAG systems ensure that generated content is both contextually relevant and grounded in factual information. This approach mitigates common challenges like hallucination and outdated responses, offering an efficient way to leverage AI for various applications, from customer support to research assistance. 

Limitations of LLMs

While LLMs have impressive linguistic capabilities, they face significant limitations:

1. Access to Private Datasets: LLMs trained on public datasets lack access to proprietary or sensitive data, limiting their use for private enterprise data and reducing their effectiveness for certain domain-specific tasks without fine-tuning or additional mechanisms.

2. Up-to-Date Information: As LLMs are trained on snapshots of data, they may not reflect recent developments, leading to outdated or irrelevant responses.

These limitations underscore the need for solutions like RAG, which enhance LLMs with the ability to retrieve and incorporate the latest and proprietary information dynamically.

Predli Studio: An Easy and Powerful Approach to RAG for your organization

Predli Studio provides customized RAG solutions designed to help organizations easily access and utilize their internal knowledge bases. This enables teams and stakeholders to find and use critical information quickly and efficiently, tailored to the unique needs of your business. For more details on how Predli Studio can benefit your organization, explore our platform. You can also learn about our collaboration with Tyréns, where we developed SvenAI, a solution that earned nominations in five categories at the Nordic DAIR Awards 2024.

Introducing GraphRAG

GraphRAG, introduced earlier this year, offers a new take on RAG systems. It integrates knowledge graphs with LLMs, combining the retrieval-based approach of RAG with the structural clarity and relationships defined in knowledge graphs. Here’s how it works:

• Dynamic Knowledge Representation: Knowledge graphs provide a structured way to represent data, capturing entities, relationships, and hierarchies. This structure enables GraphRAG to retrieve not just isolated facts but interconnected insights.

• Graph Index Creation: Source documents are divided into chunks, and an LLM extracts entities, relationships, and communities from these to construct a knowledge graph. Entities represent people, organizations, and concepts, while communities group related nodes into cohesive clusters.

• Query Processing: When a query is received, the generated answer is based on retrieved context. With GraphRAG, the retrieved context can be constructed using entities, relationships, chunks, and communities, rather than relying solely on chunks as in standard vanilla RAG. This enriched and structured approach provides a more holistic understanding of the data, enabling the LLM to generate more accurate and insightful answers.

Advanced Efficiency: LazyGraphRAG

In November, LazyGraphRAG was introduced as a more efficient alternative. Unlike the standard GraphRAG approach, LazyGraphRAG defers certain operations to query time, reducing indexing and processing costs.

• On-Demand Summarization: Constructs lightweight graphs and performs processing only as needed, ensuring efficient use of resources.

• Iterative Search Strategy: dynamically adjusts its search strategy based on a set budget. It starts by prioritizing the most relevant communities (best-first search), systematically evaluates additional content (breadth-first search), and explores deeper layers when necessary (iterative deepening), stopping when the budget is met.

Although the package is not yet publicly available, Microsoft’s evaluations indicate that LazyGraphRAG consistently outperforms regular RAG systems and, in many cases, standard GraphRAG implementations, all while operating at a fraction of the cost. This approach holds great promise for addressing the time and cost challenges associated with the indexation in GraphRAG systems.

When to Use GraphRAG Instead of Vanilla Vector RAG

GraphRAG, along with its variations, is particularly effective in addressing the following scenarios:

• Complex Data Relationships: When insights depend on understanding and analyzing connections between various data points. Examples include analyzing previous legal verdicts by a specific judge to predict outcomes and inform strategies for ongoing cases, or identifying key contributors to AI projects within an organization and evaluating their roles and impact.

• Global Insights from Large Text Corpora: For questions that require summarizing overarching themes or extracting main ideas across an entire dataset, such as “Which topics are most frequently discussed in client feedback?” or “What recurring concerns appear in annual reports across multiple years?”

At Predli, we have been conducting extensive research on GraphRAG, and are extremely optimistic about its potential to redefine how organizations access and interact with their internal knowledge efficiently. If you are interested in learning how this can bring value to your organization or are passionate about the future of knowledge graphs in RAG systems, we would love to connect.

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