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Question Answering Benchmarking: Paul Graham Essay

Here we go over how to benchmark performance on a question answering task over a Paul Graham essay.

It is highly recommended that you do any evaluation/benchmarking with tracing enabled. See here for an explanation of what tracing is and how to set it up.

Loading the data​

First, let's load the data.

from langchain.evaluation.loading import load_dataset

dataset = load_dataset("question-answering-paul-graham")
    Found cached dataset json (/Users/harrisonchase/.cache/huggingface/datasets/LangChainDatasets___json/LangChainDatasets--question-answering-paul-graham-76e8f711e038d742/0.0.0/0f7e3662623656454fcd2b650f34e886a7db4b9104504885bd462096cc7a9f51)



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Setting up a chain​

Now we need to create some pipelines for doing question answering. Step one in that is creating an index over the data in question.

from langchain.document_loaders import TextLoader

loader = TextLoader("../../modules/paul_graham_essay.txt")
from langchain.indexes import VectorstoreIndexCreator
vectorstore = VectorstoreIndexCreator().from_loaders([loader]).vectorstore
    Running Chroma using direct local API.
    Using DuckDB in-memory for database. Data will be transient.

Now we can create a question answering chain.

from langchain.chains import RetrievalQA
from langchain.llms import OpenAI
chain = RetrievalQA.from_chain_type(
    llm=OpenAI(),
    chain_type="stuff",
    retriever=vectorstore.as_retriever(),
    input_key="question",
)

Make a prediction​

First, we can make predictions one datapoint at a time. Doing it at this level of granularity allows use to explore the outputs in detail, and also is a lot cheaper than running over multiple datapoints

chain(dataset[0])
    {'question': 'What were the two main things the author worked on before college?',
     'answer': 'The two main things the author worked on before college were writing and programming.',
     'result': ' Writing and programming.'}

Make many predictions​

Now we can make predictions

predictions = chain.apply(dataset)

Evaluate performance​

Now we can evaluate the predictions. The first thing we can do is look at them by eye.

predictions[0]
    {'question': 'What were the two main things the author worked on before college?',
     'answer': 'The two main things the author worked on before college were writing and programming.',
     'result': ' Writing and programming.'}

Next, we can use a language model to score them programatically

from langchain.evaluation.qa import QAEvalChain
llm = OpenAI(temperature=0)
eval_chain = QAEvalChain.from_llm(llm)
graded_outputs = eval_chain.evaluate(
    dataset, predictions, question_key="question", prediction_key="result"
)

We can add in the graded output to the predictions dict and then get a count of the grades.

for i, prediction in enumerate(predictions):
    prediction["grade"] = graded_outputs[i]["text"]
from collections import Counter

Counter([pred["grade"] for pred in predictions])
    Counter({' CORRECT': 12, ' INCORRECT': 10})

We can also filter the datapoints to the incorrect examples and look at them.

incorrect = [pred for pred in predictions if pred["grade"] == " INCORRECT"]
incorrect[0]
    {'question': 'What did the author write their dissertation on?',
     'answer': 'The author wrote their dissertation on applications of continuations.',
     'result': ' The author does not mention what their dissertation was on, so it is not known.',
     'grade': ' INCORRECT'}