  ELO rating system is proposed by Arpad Elo, a Hungarian-American physics
professor. Originally, it was proposed for the ranking system of chess players,
but it was soon adapted to many other zero-sum sports fields like football,
baseball, basketball , etc. Nowadays, besides the traditional sports games,
computer/video games are also playing an important role in social lives
especially among the teenagers. In most of the online competition games,
player's performance is usually scored and recorded by the game's ranking
system. Meanwhile, ranking system like ladder in Dota is not the only the
metric for the players to evaluate their gaming strength, an ELO rating score
based on players in-game performance is also a decisive factor for gamers'
matching. Namely, the matching system will refer to players' score in the
ranking system and performance score system to ensure the matched players will
promisingly undergo a balanced game without one team dramatically overwhelming
the other. ELO scheme and its variants in modern online competition games aims
to ensuring the expected winning rate for each team approaches 50\%. However,
ELO rating is also causing compliments among players. In this research, I will
dig into the advantages and drawbacks of leveraging ELO ranking system in
online games and why it is still employed by game developers despite the fact
that it is disliked by most of the players. Also, a new effort based rating
scheme will be proposed and compared with ELO scheme under the simulation
environment.
