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Evaluation
 Contents 
The Problem
The Solution
The Examples
Other Examples
Evaluation#
Note
Conceptual Guide
This section of documentation covers how we approach and think about evaluation in LangChain.
Both evaluation of internal chains/agents, but also how we would recommend people building on top of LangChain approach evaluation.
The Problem#
It can be really hard to evaluate LangChain chains and agents.
There are two main reasons for this:
# 1: Lack of data
You generally don’t have a ton of data to evaluate your chains/agents over before starting a project.
This is usually because Large Language Models (the core of most chains/agents) are terrific few-shot and zero shot learners,
meaning you are almost always able to get started on a particular task (text-to-SQL, question answering, etc) without
a large dataset of examples.
This is in stark contrast to traditional machine learning where you had to first collect a bunch of datapoints
before even getting started using a model.
# 2: Lack of metrics
Most chains/agents are performing tasks for which there are not very good metrics to evaluate performance.
For example, one of the most common use cases is generating text of some form.
Evaluating generated text is much more complicated than evaluating a classification prediction, or a numeric prediction.
The Solution#
LangChain attempts to tackle both of those issues.
What we have so far are initial passes at solutions - we do not think we have a perfect solution.
So we very much welcome feedback, contributions, integrations, and thoughts on this.
Here is what we have for each problem so far:
# 1: Lack of data
We have started LangChainDatasets a Community space on Hugging Face.
We intend this to be a collection of open source datasets for evaluating common chains and agents.
rtdocs_stable/api.python.langchain.com/en/stable/use_cases/evaluation.html