Hi! I’ve learnt a lot since I joined E4 but I am still relatively new to the hobby (I got back into collecting 7 months ago). I am happy to collect and sell enough to sustain my growing collection. To do so I am trying to find my niche(s) and I thought it would be useful to develop a PSA Grading Risk Assessment Calculator (GRAC). I wanted to share it here in case it may be useful to anyone else.
GRAC
If you'd like to use the calculator yourself go to File and click Make a Copy. To use it plug in the following variables of the card you wish to evaluate:
- pop numbers
- buy price
- grading costs
- average price realized at auction
And the calculator will give you the average risk-weighted return. That’s my goal for this tool, but I understand that to evaluate a card it is necessary to consider every possible factor.
Currently, GRAC assumes that when you submit a card with a grade in mind the card may be graded up to two grades lower i.e. a hopeful PSA 10 could result in a PSA 8. A hopeful PSA 8 may result in a PSA 6.
Research Questions
Would it be beneficial to adjust degrees of freedom to accommodate different population sizes?
Is GRAC useful for helping to make an educated guess about sending cards to PSA?
Ideas!
If you have any ideas to improve this calculator please let me know! I don't remember much from my university stats courses so I'm sure this could be better optimized.
Nice sheet! The idea of assessing average return across grades would definitely be helpful. A few thoughts:
Are you including POPs below PSA 8s in the percentage or no? I’m also getting different math when I check the average but maybe I’m doing it wrong, but $160 seems very low average for almost 20% being $1600? Also curious why PSA 9s are half price of PSA 8s. Is the data pulled from PSA auction price history maybe and it’s out of date?
Don’t forget to include shipping costs and seller fees in this. You’ll need to average them in based on your sub size and platform fee based on which site you’re selling on.
Here’s an example of how I did it in my own sheet. You select the grading service & tier and it will adjust the cost according to average shipping cost based on the sub size as well as subtract middleman and ebay fees.
Thank you for taking the time to look at my sheet and offer constructive feedback. Just got back from a hike so I’m going pass out and re-evaluate tomorrow
Thank you for your thoughtful line of inquiry. I’ll do my best to respond here:
I chose to include pops of 2 grades lower than the target grade in the event that the user guesses the wrong grade. I think most people could reasonably guess within that two grade range.
What formula do you use? I’m not great with weighted averages so I had to google it. Currently my formula is (each PSA grade avg sale) x (the percent chance to get that grade) and sum all of those together. You can view the formula logic in the cell if that helps.
The example numbers I put in belong to glossy surf pikachu and the pop numbers are not that robust. For example’s sake I replaced it with the vmax gengar full art which has a pretty fleshed out pop.
What is a sub size, you mean like the size of the pack used to ship the item?
So I’m not a math genius or anything either lol but you’re right how to calculate weighted average. However, there shouldn’t a division at the end, so it should just be $908.87.
By sub size I mean how many cards you include in your submission to PSA or other company. It will affect the average shipping cost per card. I usually send about the same size sub each time but it will depend what you do you’ll have to adjust accordingly.
You’re welcome and happy to give feedback anytime! Spreadsheets are fun!
Is the data pulled from PSA auction price history maybe and it’s out of date?