The Elo Rating System (popularized in AI evaluation by LMSYS Chatbot Arena) is an adaptive ranking framework that computes global capability scores for competing LLMs via aggregated crowdsourced blind pairwise battles; given current ratings
RA,RB, model A's expected win probability is
EA=1+10(RB−RA)/4001; following a battle with outcome
SA (Win=1, Tie=0.5, Loss=0), ratings update dynamically via
RA′=RA+K⋅(SA−EA), where
K controls update magnitude.