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What is retrieval-augmented generation (RAG) and how can it reduce hallucinations in GenAI applications?

By Volodymyr Zhukov

Retrieval Augmented Generation (RAG) is a technique in natural language processing that aims to improve the accuracy and reliability of responses from large language models (LLMs) like GPT-3.

To better comprehend the concept of Retrieval-Augmented Generation (RAG), it's beneficial to understand the basics of word embedding in NLP.

RAG works by retrieving relevant information from an external knowledge base to provide additional factual context to the LLM. This helps ground the LLM on accurate, up-to-date information instead of relying solely on its training data.

Some key benefits of RAG:

  • Provides factual, specific responses instead of inconsistent, random facts

  • Allows LLMs to incorporate domain-specific information

  • Enables generative responses grounded in recent, verifiable data

  • Can reduce hallucination and improve overall quality of LLM outputs

Challenges of using LLMs alone

Large language models (LLMs) like GPT-3 and BERT have shown impressive capabilities in generating human-like text. However, when used alone, LLMs also face some key challenges:

LLMs can be inconsistent and regurgitate random facts

  • LLMs are trained on vast amounts of text data scraped from the internet

  • This training process is statistical - LLMs learn patterns but not meaning

  • As a result, LLMs may generate responses that are:

    • Inconsistent across questions

    • Contain random, irrelevant facts from training data

    • Lack a coherent underlying meaning

LLMs lack up-to-date real world information

  • Most LLMs are static after initial training

  • They lack knowledge of current events and facts

  • LLMs may generate plausible-sounding but incorrect responses about recent news or data

LLMs lack domain-specific information

  • LLMs are generally trained on open-domain data

  • They lack access to proprietary organizational data

  • Struggle to respond accurately to domain-specific questions

Consequences

  • Hallucination - generating confident but incorrect responses

  • Factual inaccuracy

  • Irrelevant responses

  • Inability to handle context-dependent queries

  • Lower quality outputs

This presents challenges in building production AI systems using LLMs. Relying solely on LLMs results in outputs that:

  • Cannot be fully trusted

  • Lack specificity and grounding in facts

  • Fail to adapt as circumstances change

Summary of LLM limitations:

LLM Limitation

Description

Consequence

Inconsistency

Statistical learning leads to irregular outputs

Lower quality, less reliable

Information staleness

Static after training, no knowledge of recent events

Factually inaccurate

Lack of domain knowledge

Trained on open-domain data only

Struggles with domain-specific queries

To address these limitations, we need solutions that provide LLMs with up-to-date, contextual information. This is where Retrieval Augmented Generation comes in.

While RAG models have their strengths, there are also alternatives to ChatGPT that are worth considering.

How Retrieval Augmented Generation (RAG) works

Retrieval Augmented Generation (RAG) is a technique that combines large language models (LLMs) with a retrieval mechanism to provide contextual information.

Retrieval-Augmented Generation (RAG) operates through a unique two-step process that sets it apart from traditional language models. This process involves both the retrieval of relevant documents and the generation of responses based on these documents.

In the first step, the RAG model receives an input, such as a question or a prompt. It then uses a retrieval system to search through a vast database of documents to find the ones that are most relevant to the input. This retrieval system is powered by a dense vector retrieval method, which allows the model to efficiently sift through the database and pinpoint the most pertinent documents.

Once the relevant documents have been retrieved, the RAG model moves on to the second step: response generation. Here, the model uses a sequence-to-sequence transformer to generate a response. This transformer takes into account both the original input and the retrieved documents, ensuring that the generated response is not only accurate but also contextually relevant.

The beauty of the RAG model lies in its ability to combine the strengths of retrieval-based and generative models. By retrieving relevant documents before generating a response, the RAG model can provide more accurate and contextually appropriate responses than traditional language models. This makes RAG models particularly useful for tasks such as question answering and dialogue systems.

The overall workflow is:

  1. Retrieve relevant facts, documents, or passages using a retrieval model

  2. Provide the retrieved information as additional context to the LLM

  3. LLM generates an informed, grounded response

Retrieval Models

RAG relies on efficient retrieval models to find relevant information from a knowledge source given a query:

  • BM25: Probabilistic retrieval model based on term frequency and inverse document frequency

  • TF-IDF: Weights terms based on rarity across corpus

  • Neural network embeddings: Maps text to vector representations and finds semantically similar passages

Providing Retrieved Context

  • The top retrieved results are concatenated into a context document

  • This context document is provided to the LLM along with the original query

  • The LLM leverages the retrieved information to inform its response

LLM Generation

  • With relevant context, the LLM can generate responses that are:

    • Factual and specific

    • Grounded in the provided information

    • More accurate and relevant to query

  • Avoids hallucination and arbitrary responses

Differences from LLM alone

RAG differs from using an LLM alone in a few key ways:

  • Dynamic - retrieves recent facts instead of relying solely on static training data

  • Incorporates external knowledge through retrieval mechanism

  • Provides relevant context to anchor the LLM

  • Allows tracing outputs to retrievals and improves auditability

RAG offers an efficient way to improve responsiveness and accuracy of LLMs by complementing their capabilities with retrievals.

Benefits of using RAG

Embracing Retrieval-Augmented Generation (RAG) brings a host of advantages that can significantly enhance the performance of AI systems. Here are some key benefits:

1. Enhanced Accuracy: By retrieving relevant documents before generating a response, RAG models can provide more accurate and contextually appropriate responses. This is a significant improvement over traditional language models that generate responses based solely on the input they receive.

2. Scalability: RAG models are designed to work with large databases, making them highly scalable. They use a dense vector retrieval method to efficiently sift through vast amounts of data, ensuring that the size of the database doesn't compromise the model's performance.

3. Versatility: The two-step process used by RAG models makes them versatile and adaptable. They can be used for a wide range of tasks, from question answering and dialogue systems to AI-powered knowledge management and enterprise search systems.

4. Continuous Learning: RAG models are capable of continuous learning. As they interact with more data, they become better at retrieving relevant documents and generating accurate responses. This ability to learn and improve over time makes RAG models a valuable asset in the rapidly evolving field of AI.

5. Autonomy: By enhancing the accuracy and relevance of AI responses, RAG models contribute to the development of autonomous digital enterprises. They improve the efficiency and effectiveness of AI systems, enabling businesses to automate more processes and make more data-driven decisions.

Retrieval Augmented Generation (RAG) provides several key benefits over using large language models (LLMs) alone:

Provides LLMs with up-to-date, factual information

  • RAG retrieves recent facts and data from updated knowledge sources

  • Overcomes limitation of LLMs being static after training

  • Reduces hallucinations and factual inconsistencies

  • Enables generating responses grounded in the latest information

Enables LLMs to access domain-specific information

  • RAG allows injecting domain knowledge from proprietary data

  • LLMs can incorporate organization-specific data unavailable during training

  • Vastly improves performance on domain-specific queries

  • Contextual responses aligned with business needs

Generates more factual, specific and diverse responses

  • Retrieved facts make outputs more specific and factual

  • Wider range of external knowledge increases diversity

  • Mitigates generic, inconsistent LLM responses

  • Evaluation shows RAG improves correctness on benchmarks

Allows LLMs to cite sources and improves auditability

  • RAG provides the LLM with context documents

  • Responses can be traced back to original retrievals

  • Enables explaining outputs and sources to users

  • Critical for domains like law, finance that require audit trails

More efficient than retraining LLMs with new data

  • Retraining LLMs is time-consuming and computationally expensive

  • RAG achieves accuracy gains by simply providing new context

  • Faster way to incorporate updated knowledge vs. LLM retraining

  • Saves time and money while boosting performance

Other Benefits

  • Customizable based on use case - index any knowledge source

  • Can be implemented incrementally to augment existing systems

  • Enables hybrid approaches that combine its strengths with LLMs

The integration of RAG models is a significant step towards unifying LLMs and knowledge graphs.

Summary

Benefit

Description

Up-to-date information

Pulls latest facts dynamically

Domain knowledge

Incorporates proprietary data

Improved quality

More accurate, factual and specific

Auditability

Can trace outputs to sources

Efficiency

Faster and cheaper than LLM retraining

RAG provides a flexible, efficient way to boost LLM performance for production systems.

Applications of RAG

Retrieval augmented generation (RAG) has diverse applications across many industries. RAG can enhance large language models (LLMs) in systems for:

Question answering

  • RAG is highly effective for question answering systems

  • Retrieval model finds relevant facts or passages with answers

  • LLM formulates complete answer using retrieved context

  • Improves accuracy on benchmarks like Natural Questions

RAG models are instrumental in AI powered knowledge management systems, enhancing their ability to retrieve and generate relevant responses.

Content generation

  • Can aid tasks like summarization, story generation, etc.

  • Retrievals provide factual details and context

  • LLM integrates facts into coherent narratives

  • Outputs are more informative and engaging

Reducing hallucination in LLMs

  • Hallucination is a key risk when using LLMs

  • RAG mitigates this by grounding LLM on retrieved info

  • Constraints LLM responses to provided context

  • Lowers chances of arbitrary or incorrect responses

Customer service and chatbots

  • RAG enables chatbots to incorporate customer data

  • Can retrieve customer history and profile information

  • Allows providing personalized and contextually relevant replies

  • Significant benefits for customer service use cases

Domain-specific implementations

  • Legal: Retrieve relevant case law and precedents

  • E-commerce: Fetch product specs, inventory, orders

  • Finance: Incorporate market data, risk models

  • Healthcare: Use medical ontologies, patient records

  • Custom index of domain knowledge

Other applications

  • Structured data retrieval from databases

  • Real-time event and news tracking

  • Integrating multimedia information

  • Incorporating organizational policies

  • Numerous possibilities based on indexed knowledge

Example Implementations

Industry

Knowledge Source

Use Cases

Legal

Case law, precedents

Litigation support, contract review

E-commerce

Product catalogs, orders

Customer support, product recommendations

Finance

Market data, risk models

Investment advice, compliance

Healthcare

Ontologies, patient records

Diagnosis support, personalized care

RAG is a flexible technique that can enhance LLMs across many verticals by grounding them in specialized knowledge.

The power of RAG models is evident in their application in AI-powered enterprise search systems.

Conclusion

In summary, Retrieval Augmented Generation (RAG) offers an effective technique to overcome key limitations of large language models (LLMs) and improve the quality and specificity of AI system outputs.

Key strengths of the approach

  • Combines strengths of performant retrieval models and creative LLMs

    • Retrieval provides relevant facts and context

    • LLMs generate fluent, coherent responses

  • Enables dynamic, up-to-date responses by retrieving recent information

  • Handles domain-specific use cases by injecting organizational data

  • Reduces hallucination by grounding LLMs on retrievals

  • Improves auditability by tracing LLM responses back to sources

  • More efficient alternative to ongoing LLM retraining

Range of applications

  • Question answering systems

  • Chatbots and customer service

  • Content generation

  • Reducing hallucination

  • Domain-specific implementations in legal, healthcare, e-commerce, and more

Future directions

Some promising areas for further development of RAG:

  • Advanced retrieval models like dense retrievers to improve context

  • Methods to retrieve structured, multimedia data

  • Tighter integration between the retriever and LLM components

  • Hybrid approaches combining RAG strengths with other techniques

  • Scaling RAG across massive corpora and datasets

It models play a pivotal role in the evolution towards an autonomous digital enterprise.

RAG provides an important tool for building production-ready AI systems that can meet business needs for accuracy, specificity, and relevance. As LLMs continue advancing, RAG offers an efficient method to improve their capabilities and ground them in real-world knowledge.

When it comes to choosing the best AI search engine, the capabilities of RAG models can't be overlooked.

With further innovation in retrieval methods and system integration, RAG is poised to enable the next generation of useful, reliable AI applications across many industries.

FAQ

Retrieval-Augmented Generation (RAG) is a revolutionary AI model that combines the best of retrieval-based and generative systems. It uses a two-step process to generate responses, first retrieving relevant documents and then generating a response based on the retrieved documents.

Traditional language models generate responses based solely on the input they receive. In contrast, RAG models retrieve relevant documents from a database before generating a response, allowing them to provide more accurate and contextually relevant responses.

RAG models are instrumental in AI powered knowledge management systems and AI-powered enterprise search systems. They enhance the ability to retrieve and generate relevant responses, making them ideal for tasks such as question answering, dialogue systems, and more.

Yes, there are alternatives to RAG models, such as ChatGPT. While RAG models have their strengths, it's important to consider different models based on the specific requirements of your task.

RAG models play a pivotal role in the evolution towards an autonomous digital enterprise by enhancing the ability of AI systems to retrieve and generate accurate, contextually relevant responses. This improves the efficiency and effectiveness of AI systems, contributing to the development of autonomous digital enterprises.

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