What do you want to be the determining factor?
Goals conceded?
Goals conceded per minute?
Lowest against?
Most saves?
That's how they award goalkeeper awards overseas as well.
Not saying it's deterministic of the "best goalkeeper" but it's the goalkeeper with the most clean sheets.
Same as the player with the most goals gets the golden boot or "striker Of the year". Maybe they aren't the best striker but they scored the most goals.
Maybe a terminology chance to "golden glove".






