Odds of Different PSA Grades?

hamilton989 · April 17, 2020 5:11AM

I am programming a vintage pack "simulator" in which users can simulate the experience of opening wax packs from different years. Furthermore, to be able to show a predictive ROI, for example, to calculate the relative values of individual cards versus the price of the pack. To execute this, I am trying to determine the approximate probabilities of obtaining different PSA values from, for example, a 1986-87 Fleer Basketball pack. This doesn't have to be perfect, just "fairly close." I am working with these assumptions and using the 86-87 fleer pack as an example. The percentage chance that any given card is:

PSA 6 - 5%
PSA 7 - 30%
PSA 8- 30%
PSA 8 - OC - 20%
PSA 9 - 10%
PSA 10 - 1%
Other - 4%

This is assuming the pack is not tampered with. Does this remotely close? I'd highly value your thoughts. Thank you.