"Weighted GPA", "set rating"...

Steve1124

Can anyone explain, or show me where these terms are defined, and what FORMULA is used to determine a PSA Registry set's score? Do the collectors have a say in what determines the "weight" of a card--i.e. it's scarcity, which ultimately affects the scores? Seems that since it's the collector who spends months, even years, and much money on building a set, it is US that know it's true scarcity. I'd like to see a link somewhere on the PSA Set Registry site (maybe it's there, but i just haven't seen it) that goes into an explanation of how this all works.

kingraider75

Seems like the star or "money cards" get what a 10 factor, SP lesser stars around 5 or 6 and other get a 1 factor. I, too have no idea how that was determined.

wolfbear

Here's basically how it works.
I've made up a small pretend set of 10 cards,
but the same principles apply regardless of the set size.

The weight for each card is based roughly on the dollar value
of each card compared to the other cards in the set.
The exact weight number is determined by whichever collector submits the list to PSA,
but is subject to approval and tweeking by the registry people at PSA.

Pretend set using only as an example :

1. - common, but 1st card in set : weight = 2
2. - common : weight = 1
3. - common short-print : weight = 2
4. - semi-star : weight = 3
5. - semi-star short-print : weight = 5
6. - big star : weight = 9
7. - common short-print : weight = 2
8. - minor star : weight = 4
9. - common : weight = 1
10. - semi-star and last card in set : weight = 4

When you add up all the weights in this set you get the number 33, which becomes the divisor for this set.

Say you had cards in the set in the following grades :

1. - weight 2 times PSA 7 = 14
2. - weight 1 times PSA 8 = 8
3. - weight 2 times PSA 6 = 12
4. - weight 3 times PSA 7 = 21
5. - weight 5 times PSA 9 = 45
6. - weight 9 times PSA 9 = 81
7. - weight 2 but no card
8. - weight 4 times PSA 7 = 28
9. - weight 1 times PSA 6 = 6
10. - weight 4 times PSA 8 = 32

Add those numbers up and you get 247.
No card # 7, so deduct the weight of 2 from the divisor of 33 for 31.
Divide 247 by 31 and you get 7.96 which is your set GPA.

Your 'Set Rating' can be determined by dividing the 247 by the set divisor which would be 7.48

See, it's all really very simple ...

NickM

PSA makes the final weight decisions, but they do listen to input from collectors. If multiple participants in a set registry collaborate on a weighting for a large group of cards, PSA is highly likely to listen to it. If a collector points out a serious weighting discrepancy on one or two cards in a set (such as when the '72 Topps Staubach Pro Action had a weight of 8 or 9, when the card routinely sells for less than a high number common), PSA is highly likely to listen to it. If one collector wishes to weight a set that has never been weighted, PSA is highly likely to listen to it. If a collector, however, wants to undertake a reweighting of a set by himself when many others are collecting that set, PSA won't give it that much consideration.

Nick

tennesseebanker

How come some pretty decent sets are not weighted? I noticed this when I started building the 83 topps football set. Granted this is not the 52 topps baseball , but i thought it would at least be weigted. A gem mint marcus allen is 5-600 hundred bucks.

kingraider75

PSA is bias toward vintage.

Amazing how tough it is to find a Gem mint card that was DP. Marcus Allen was an awesome player, Al Davis shafted him! Anyways, maybe you can let PSA know, then they might have someone weight the set.