One comment and one question for Cheetah.
Comment: Piggybacking off of the other boardies' insights, one issue is the criterion. Specifically, it would be nearly impossible for any grader to submit exactly the same grades as CGC because there is variability within their own ratings.
Let me make it clear, I'm NOT knocking CGC; it's just the reality of this line of work. One question might be, given two different rater teams at CGC rating the exact same books, what percentage would be an exact match? If it were 75% that would be amazing. The truth is that there are many books that are right on the border of grades. If God's rater were to evaluate them they would receive 1.9s, 7.75s, 9.1s, etc. The problem is that people just can't be trained to make such distinctions consistently. In earthly operations, the "1.9" will be 1.8 half of the time, and 2.0 half of the time. That type of error is inescapable. You can't stop rating error, you can only hope to contain it
Question for Cheetah. Could you post scans of the most severely over-rated books (8GIs!!)? Assuming that there wasn't foul play, those books must have posed some unusual rating challenges. I would love to hear your hypotheses about why these books threw off raters so badly.
Again, AWESOME job Jeff!