Thread:User talk:Chase-san/Approximate ELO/reply

For a precise ELO calculation you would need the full pairwise matrix. But for an approximation based on an APS column, it looks good.

Another way to deal with rating drift (without the full pairwise matrix) is calculating the average of all ELO ratings, then calculate the difference from the average to 1600, then add/subtract the difference to all drifted ratings. So you have ratings centered around 1600. Works with both ELO and Glicko-2 ratings columns.