AI & ML

Evaluating LLMs in Production: Metrics That Matter

SK

Sarah Kim

Principal AI Engineer

Nov 28, 2025
7 min read

# Evaluating LLMs in Production

Moving LLMs from prototype to production requires a robust evaluation framework. Standard machine learning metrics often fail to capture the nuances of generative AI.

1. Beyond ROUGE and BLEU Traditional NLP metrics like ROUGE and BLEU are insufficient for evaluating creative or complex outputs. Instead, focus on: * **LLM-as-a-Judge**: Using a larger model (GTP-4) to grade the output of a smaller model. * **Deterministic Tests**: Checking for specific keywords, JSON structure, or valid code.

2. Human-in-the-Loop Automated metrics are only half the story. Implement a "thumbs up/down" feedback loop in your UI to collect ground-truth data from actual users.

3. Latency vs. Quality In production, every millisecond counts. We measure "Time to First Token" (TTFT) and "Tokens Per Second" (TPS) alongside semantic accuracy.