Decoder. plain-English AI glossary

Grader

▲ Rising

A function or model that takes a model's output and a reference and produces a score—automating the evaluation step.

Think of it like

Like an automated essay grader that reads your essay and assigns a score.

Example

Grader function: takes model output and gold answer, returns 1 if correct, 0 if wrong. Used in eval pipeline.

How it actually works

Graders can be rule-based (exact match, length checks) or learned (LLM-as-judge, a fine-tuned model trained to score outputs). Learned graders are more flexible but require training data. Graders should be fast (not calling APIs repeatedly) and deterministic when possible.

For product teams

Good graders are force-multipliers. They let you evaluate at scale.

For engineers

Build deterministic rule-based graders for simple metrics; train graders for complex judgments.

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