Straight off the PSA website:
Each grader receives the order and they will enter the order number into the computer. Once that is done, the contents of that order will appear on the PSA grading screen. Grader #1 will then enter his grade for the card in question (and for each card within the order until the order is completed if there is more than one card) and close the order on his screen. Once that is done and after redistribution of the order, Grader #2 will do the same - not knowing the opinion of the first grader on any of the cards within that order.
If their grades match in the computer, the card would then eventually reach a 3rd grader for verification of the grade. If the opinion of the first two graders does not match, that card will be assigned to a 3rd grader whose opinion is required to break the tie so to speak. As with the first example, the card would still be assigned to another grader for verification (a 4th grader in the process) to make sure the grade is accurate and consistent with our standards.
They forgot to mention if you don't like the opinions of the original 2-3 graders and the grader assigned to verify that it is accurate and consistent with their standards you can resubmit it and overrule them by writing your own grade in on the minimum grade column.
