The task involves improving a Retrieval-Augmented Generation (RAG) application’s performance by experimenting with embedding models. The choice of embedding model impacts retrieval accuracy,which is critical for RAG systems. Let’s evaluate the options based on Databricks Generative AI Engineer best practices.

Option A: Pick an embedding model trained on related domain knowledge

Embedding models trained on domain-specific data (e.g., industry-specific corpora) produce vectors that better capture the semantics of the application’s context, improving retrieval relevance. For RAG, this is a key strategy to enhance performance.

Databricks Reference:"For optimal retrieval in RAG systems, select embedding models aligned with the domain of your data"("Building LLM Applications with Databricks," 2023).

Option B: Pick the most recent and most performant open LLM released at the time

LLMs are not embedding models; they generate text, not embeddings for retrieval. While recent LLMs may be performant for generation, this doesn’t address the embedding step in RAG. This option misunderstands the component being selected.

Databricks Reference: Embedding models and LLMs are distinct in RAG workflows:"Embedding models convert text to vectors, while LLMs generate responses"("Generative AI Cookbook").

Option C: Pick the embedding model ranked highest on the Massive Text Embedding Benchmark (MTEB) leaderboard hosted by HuggingFace

The MTEB leaderboard ranks models across general tasks, but high overall performance doesn’t guarantee suitability for a specific domain. A top-ranked model might excel in generic contexts but underperform on the engineer’s unique data.

Databricks Reference: General performance is less critical than domain fit:"Benchmark rankings provide a starting point, but domain-specific evaluation is recommended"("Databricks Generative AI Engineer Guide").

Option D: Pick an embedding model with multilingual support to support potential multilingual user questions

Multilingual support is useful only if the application explicitly requires it. Without evidence of multilingual needs, this adds complexity without guaranteed performance gains for the current use case.

Databricks Reference:"Choose features like multilingual support based on application requirements"("Building LLM-Powered Applications").

Conclusion: Option A is the best strategy because it prioritizes domain relevance, directly improving retrieval accuracy in a RAG system—aligning with Databricks’ emphasis on tailoring models to specific use cases.