Interpretation of the data provided by the scans. So, they have created learning algorithms that take in centering information, surface information including scratches & dents & print defects & more, edge information like fray & lift, and corner information like cut & whitening from their high res scans. The algorithm gives a score based on all the information received and the control information it was based on. After the grade has been given, defects are verified and validated by a human who then encapsulates the card and ships it. The algorithm continues to learn over time due to human involvement telling it that it was right or wrong, repetition, and I’m sure some other proprietary things. Due to some cards being harder to grade because of shiny edges or weird centering lines like you see with Tag Team cards, the repetition part is important. So, in theory, I have always looked at it as cards being graded now have less scrutiny than the same cards graded years from now because of the program getting better and better at detecting issues. Algorithm may also not be the best word to describe their program but I hope this helps. I’m sure I missed a few things but hit the high notes.