# ContextQAEvalChain

> **Class** in `langchain_classic`

📖 [View in docs](https://reference.langchain.com/python/langchain-classic/evaluation/qa/eval_chain/ContextQAEvalChain)

LLM Chain for evaluating QA w/o GT based on context.

## Signature

```python
ContextQAEvalChain()
```

## Extends

- `LLMChain`
- `StringEvaluator`
- `LLMEvalChain`

## Properties

- `requires_reference`
- `requires_input`
- `model_config`
- `evaluation_name`

## Methods

- [`is_lc_serializable()`](https://reference.langchain.com/python/langchain-classic/evaluation/qa/eval_chain/ContextQAEvalChain/is_lc_serializable)
- [`from_llm()`](https://reference.langchain.com/python/langchain-classic/evaluation/qa/eval_chain/ContextQAEvalChain/from_llm)
- [`evaluate()`](https://reference.langchain.com/python/langchain-classic/evaluation/qa/eval_chain/ContextQAEvalChain/evaluate)

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/f0c5a28fa05adcda89aebcb449d897245ab21fa4/libs/langchain/langchain_classic/evaluation/qa/eval_chain.py#L219)