For coin grading companies there is another third party company that verifies if your coin’s grade was graded accurately. Coins get a sticker on the grading case that give the grade approval. I’ve said this many times and it gets ignored but PSA is very accurate however what are the quantifiable deductions that makes a card a 9 and not a 10. You see factory wear that one grader thought still had the eye appeal but another card with the same corner wear but is centered no surface damage get a 9.
Someone broke it down simply for me. What one grader believes is a 9 to 10 is different from what another grader believes is a 9 or 10. If we are complaining about 9 to a 10 then PSA is accurate but that slight difference in grade makes for hundreds to thousands of dollars difference (or for us with strict collection goals a big headache).
Back to the question about third party verification and who regulates PSA. You can say argue what you want but none of us truly knows what’s going on. I think 90% of the time all things are working as they should be.