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G-Eval

G-Eval is an LLM-based technique for evaluating generated text against natural-language criteria, often by generating evaluation steps and assigning scores.

How 2 Manning books explain it

Machine Learning Platform Engineering

G-Eval is an evaluation technique that uses a large language model to judge another model’s outputs against natural-language criteria.

How it is used
Tests assistant responses against domain-specific quality and safety criteria.
How deep it goes
Works through criteria, test-case fields, thresholds, and combined metrics; does not detail the judge model’s internals.
Examples
Uses a security-sensitive credentials request, correctness and completeness tests, and documentation-grounded hallucination checks.
What you can do after
Apply it via DeepEval to test response quality and safety against configurable criteria and thresholds.

Read how Machine Learning Platform Engineering explains G-Eval →

Generative AI in Action

G-Eval is an LLM-based framework for evaluating generated text according to specified quality criteria without requiring reference texts.

How it is used
Evaluates generated text when suitable reference answers are unavailable, including summaries and case-specific content.
How deep it goes
Works through criterion prompts, scoring steps, an API call, and score comparison without deriving model internals.
Examples
Compares an NLP-generated summary with an LLM-generated summary using relevance, coherence, consistency, and fluency scores.
What you can do after
Apply it via Azure OpenAI GPT-4 to score and compare summaries against defined criteria.

Read how Generative AI in Action explains G-Eval →

Related concepts

These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.