A data driven approach to slab gem rate

Grading
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after doing some internet reading, my impression was that psa is tougher on vintage than cgc.

I decided to take a data driven approach, and compile the data myself. I compared roughly 1100 cgc cards to about 5000 psa cards, all within the same set, with the goal of finding statistical likelihood for 8,9,or 10 grade from each company.

the results were interesting to say the least. The first data table is for the holos in the set

Range CGC PSA
10+ 2.6% 1.4%
9–9.5 9.4% 13.6%
8–8.5 21% 37%

Now this is where is gets interesting. This is for non holos

Range CGC PSA
10+ 2.6% 8.3%
9–9.5 10.3% 38.5%
8–8.5 38.9% 62.9%

I thought it was shocking to see the gem rate difference on the non-holo. It’s a limited data set, but I think it’s enough to understand the potential opportunity. It appears CGC is tighter at the top, and that many CGC grades are compressed towards the middle. Perhaps people submit more “junk” to cgc than psa and skews the numbers?

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Thanks for sharing! Its nice seeing data reinforce a lot of submitters experiences. A few thoughts, having the quantity for each would be useful. If I had to guess why the PSA NH 10’s are higher, since they are lower value, people primarily submit potentially mint-gem copies. This is something I do, and am probably one of the larger WOTC NH submitters.

Another aspect is more cards submitted to cgc are used for mystery packs. There is less concern about individual value. Not to say that isn’t happening with PSA, but more likely a higher rate with CGC. From that perspective, the conditional value isn’t as relevant. Where if the focus is on individual value, conditional value is the primary goal.

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There are documented differences between how PSA and CGC grades cards between sets.

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Thanks for sharing this data. We can infer from this that CGC has a much higher rate of grading these vintage cards below 8.

Similar to what @smpratte commented above, this shows that people are most likely submitting higher quality cards to PSA than CGC.

Anecdotally, a LCS near me has stacks and stacks and stacks of vintage CGC graded cards in low grades (i.e. junk slabs), that just would not be financially worth it to send to PSA.

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