Part 1. Definition
Given a prompt and two completions from a language model, select the completion that is the most fluent with respect to continuing the prompt. Fluency is defined by coherency and ease of understanding, not necessarily grammatical correctness. Generate either Completion A or Completion B.
Part 2. Example
Prompt: Im 99 percent sure it was someone being an 
Completion A: accomplice , or maybe just plain old con man . whatever it was , it 's over . " 
Completion B: asshole, your right?) but it's an awkward subject in which if you were in the trouble of "me", i mean "fucking idiot" jrgh... i dunno...I guess you are (in a legal context) not a stupid
Answer: Completion A
Explanation: This prompt-completion pair is more fluent because it is more easy to follow and is a realistic statement.
Part 3. Exercise
Prompt: Most people compared the Andrew Luck & RG3 draft to Manning and Leaf. 
Completion A: This makes sense if you look at what Luck did at that time (2014) and how good RG3 is now. But if we look back at 
Completion B: Luck won the 2015-2016 Pro Bowl MVP Award last season after leading the Colts to their first playoff spot in four years. R
Answer:
Completion A