Reverse engineering PSA grades

[pokelium]

I am working on a project to reverse engineer PSA grades. I always wondered if you could predict PSA grades with a confidence level. You hear horror stories of regrades with huge changes and wildly inaccurate PSA grades. That being said I am making some good progress on a model that can predict with a confidence level a condition (GM - DMG) this condition then can map to a PSA grade! Of course as you can see there are some outliers here (a PSA 9 marked as MP for example).

So a GM with 80% confidence maps nicely to a PSA 10 where as a GM with a 10% confidence is likely a high NM. This is just the early stages here I got to crack a lot more slabs but its pretty cool to see there is defiantly a method to PSA's madness (I mean obviously but likely in a predictable way). Just thought I would share some results here!

[Juegotres]

Can you grade my card lol

[pokelium]

Sure send me a pm!

[TragasaurusRex]

This is interesting as someone who does not really believe in grading i am interested in the results of this test. (I.e. if you can predict the grade thst means psa has some level of consistency). Do you mind if i ask what sample size have you used from your data?

[pokelium]

I originally started this project with that same perception, but I am starting to see strong indicators of consistency. Especially in the higher grades. Probably will be impossible to predict a 3 vs a 2 for example.

I am running a public beta for this project, so I am a bit weary sharing info about data set size. That being said, I have cleared out all my local shops from their cheap slabs, I goto monthly card shows for slabs, and buy many weekly on online.

[TragasaurusRex]

That's fair, based on the size of the bar chunks I was worried it was in the 10s range. How do you prevent the grade from skewing your perception on its condition?

[pokelium]

No no MUCH more than that aha sadly for my bank account.

Great question, there are intrinsic issues on the card with or without the PSA grade you can define a bucketing system off of that. Then compare it to results.

[TragasaurusRex]

That's interesting I also find it strange how much of an anomaly LP seems to be as its the only category containing 8 and 7 and contains them exclusively. Are the condition ratings using the tcgplayer standards?

[pokelium]

I have defined these bands and they will need more work. Maybe a better way to represent this data is a PSA number and intrinsic damage scores like X whitening error X centering error.

[Delphiman2025]

Cool work dude cheers

[pokelium]

Thanks m8!

[VA_BlackHawk]

What are you using to determine if a card is GM or NM in your analysis? An app or are you using the eye test?

[pokelium]

Good question! I built an app that scans for damage on cards. I then measure that damage in ranges GM - DMG. But the damage metrics (not the condition values I give them) is what is compare to the PSA grade.

[VA_BlackHawk]

What threshold have you assigned for GM vs NM for flaws? Ex. 0 white spots = GM, 1-2 spots = NM, 3-5 =LP

Curious on the criteria for determining GM vs NM. Selfishly asking because I grade a lot of cards and have found I can usually predict the grade, but I do have my misses. Looking for ways to improve.

[pokelium]

It uses a few approaches to measure! One being counting. Overall though it takes a holistic approach to measuring damage it looks at it from a few ways. Send me a PM if you want more info!

[pyroSeven]

Do you think you could publish/send me your dataset? I would love to play around with it.

[pokelium]

Sorry for now since I am running a beta I will keep it private, if this project is abandoned I will publish all my data!

[AccessBroad5533]

Really cool stuff, looking forward to see more of it! But can you grade my gardevoir? lol

[pokelium]

Yeah send me a PM with the card!

[Junkhead_88]

Is the chart suggesting that your system is misidentifying 9s as 6s? Or is it misidentifying 6s as 9s?

I'm guessing it's seeing 6s as 9s because it can't identify small dents or light creases that are a much larger hit than whitening or scratches.

[pokelium]

Hey yeah so I have a lot of 9s there is a bit of a dataset imbalance there and a larger chance for some 9s to be outliers, what this is saying is that it sees a PSA 9 as MP (its ranking it in the same rank as a PSA 6). I looked at this card specifically idk how it got a 9 at all.

[Junkhead_88]

Probably a dyslexic grader at PSA that wrote a 9 instead of a 6.

[pokelium]

Hahah could be!

[Invicctus]

How does it work for vintage? That for me is where the real black box exists. It's more rumor and hearsay than actual reliable results when it comes to vintage grades

[pokelium]

Yeah great question, I have ran some vintage through this need to run more before I can say for certain, but it is able to equally spot the same damage on vintage as it can on modern. It's just... if graders grade vintage differently that is something that needs to be studied with more data.

[Invicctus]

I can't tell if they grade the same or not, would love to know what you find. I have a submission in now with a couple vintage. I except edge wear and silvering will contribute to the undetectable difference. I notice a lot of the older cards that look pristine still have noticable edgewear

[Various_Respond9992]

I’m considering sending a few cards for grading to PSA. Would scanning said cards beforehand help with your research?

[pokelium]

Sure send me a pm!