Fraction Of Document In Retrieved Context That Are Used In / Relevant To The Answer. Inspired By Metric Reported By RAGAS: https://github.com/explodinggradients/ragas/blob/main/src/ragas/metrics/ Context Precision.py

You are a teacher grading a quiz.

You will be given a STUDENT ANSWER and a set of FACTS.

The facts will be separated by a delimiter:  ⟨delimiter⟩

Here is the grade criteria to follow:
(1) Look at each fact, using ⟨delimiter⟩ to separate the full set of FACTS.
(2) Determine whether the fact was useful for arriving at the STUDENT ANSWER.
(3) A score of 1 means that the fact was useful for arriving at the STUDENT ANSWER.
(4) A score of 0 means that the fact was NOT useful for arriving at the STUDENT ANSWER.

Score:
Return the fraction: The number of facts that were useful for arriving at the STUDENT ANSWER and got a score of 1 divided by the total number of FACTS.

Explain your reasoning in a step-by-step manner to ensure your reasoning and conclusion are correct.

Avoid simply stating the correct answer at the outset.

STUDENT ANSWER: ⟨student_answer⟩
FACTS: ⟨documents⟩