Comparison
LLM-as-Judge vs Online Evaluation
LLM-as-Judge and Online Evaluation are both common AI/LLM terms but cover different ideas. Here is a quick side-by-side.
When you would reach for LLM-as-Judge
When you need to evaluate thousands of open-ended outputs cheaply and quickly.
MT-Bench: GPT-4 scoring 80 multi-turn questions.
When you would reach for Online Evaluation
After offline eval is solid and you have meaningful production volume. Stretch your eval coverage from a fixed set to a live one.
Phoenix running a faithfulness eval on 5% of production RAG traces, dashboard charts the rolling 7-day mean.
Frequently asked
What is the difference between LLM-as-Judge and Online Evaluation?
LLM-as-Judge: LLM-as-judge uses a strong LLM to score or compare outputs from other LLMs. It is how most production teams evaluate quality at scale when human review is too slow. Online Evaluation: Online evaluation runs scoring functions over live production traffic — usually a sample of recent traces — to monitor quality continuously instead of relying solely on a fixed offline dataset.
When should I use LLM-as-Judge vs Online Evaluation?
When you need to evaluate thousands of open-ended outputs cheaply and quickly. After offline eval is solid and you have meaningful production volume. Stretch your eval coverage from a fixed set to a live one.
Are LLM-as-Judge and Online Evaluation the same thing?
No. LLM-as-Judge is evaluation; Online Evaluation is evaluation. They are related but address different parts of the AI stack.