# CotQAEvalChain

> **Class** in `langchain_classic`

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

LLM Chain for evaluating QA using chain of thought reasoning.

## Signature

```python
CotQAEvalChain()
```

## Extends

- `ContextQAEvalChain`

## Properties

- `evaluation_name`

## Methods

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

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/42f8f79293cfb7589e5bc1d74a8ae4dfd0bf15e3/libs/langchain/langchain_classic/evaluation/qa/eval_chain.py#L350)