# Summarization coherence

`SummarizationCoherenceJudge` evaluates the writing quality of a summary: structure, clarity, and logical flow. It complements `SummarizationConsistencyJudge` by focusing on how the summary reads rather than whether it is factual, returning a 0.0–1.0 score derived from a raw 0–10 judgement.

```python title="Improving summary readability"
from opik.evaluation.metrics import SummarizationCoherenceJudge

metric = SummarizationCoherenceJudge()

score = metric.score(
    output="""SUMMARY: First, the product launched. Revenue grew. Margins fell. Next steps TBD.""",
)

print(score.value)   # 0.0–1.0 after normalisation
print(score.reason)
```

## Inputs

| Argument | Type  | Required | Description                                                         |
| -------- | ----- | -------- | ------------------------------------------------------------------- |
| `output` | `str` | **Yes**  | Summary text to evaluate.                                           |
| `input`  | `str` | Optional | Original document/talk track for additional context (not required). |

## Configuration

| Parameter      | Default      | Notes                                                          |
| -------------- | ------------ | -------------------------------------------------------------- |
| `model`        | `gpt-5-nano` | Upgrade when assessing long-form or domain-specific summaries. |
| `temperature`  | `0.0`        | Raise slightly (≤0.3) to expose diverse stylistic critiques.   |
| `track`        | `True`       | Toggle off to skip logging.                                    |
| `project_name` | `None`       | Override when tracking across projects.                        |

Pair this judge with `SummarizationConsistencyJudge` to ensure summaries are both factual and easy to skim. The evaluator returns a 0–10 integer that Opik normalises to 0–1.

## Related pages

- [Overview](./evaluation-metrics-overview.md)
- [Heuristic metrics](./evaluation-metrics-heuristic-metrics.md)
- [Hallucination](./evaluation-metrics-hallucination.md)
- [LLM Juries](./evaluation-metrics-llm-juries.md)
- [G-Eval](./evaluation-metrics-g-eval.md)
- [Conversation-level GEval Metrics](./evaluation-metrics-g-eval-conversation-metrics.md)
- [Compliance risk](./evaluation-metrics-compliance-risk.md)
- [Prompt uncertainty](./evaluation-metrics-prompt-diagnostics.md)
- [Moderation](./evaluation-metrics-moderation.md)
- [Meaning Match](./evaluation-metrics-meaning-match.md)

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