How to Use ELO Ranking for Team Deathmatch with Formula and Example

Include example file, you can get it here if you don't want to scroll :)

Have you ever wondered about Ranked Play mechanism of League of Legends, DOTA2 and Overwatch? Maybe you read about it somewhere, that they use the so-called ELO system to calculate the points gained/lost after match.



Let's assume you want to  build the same thing for the coming game, and Riot or Valve isn't going to reveal how they implement the system, which let us to this post.

So, make it short, I'm going to show you how to use the ELO system for Team Deathmatch (a mode in which two teams consist of player with the same skill are gathered and fight for victory). Although this term is widely used for FPS game,

I believe it's OK if we considered League of Legends and DOTA 2 are, at core, Team Deathmatch

Introducing ELO Rating System

I'm not going into details about this system since you can find a lot of useful information here on Wiki

In a nutshell, this system introduces a way to calculate the relative skill levels of players in competitor-versus-competitor games, such as chess. And although it was first used as a way to improve chess rating system, ELO Rating system has found its way into many video games with the PvP mode.

Please note, ELO itself has its own strong and weak points and isn't the only rating system in the world, so you can find other system to suit your needs.
In my opinion, the strong and weak points of the ELO system are

Strong Points 

• Easy to Understand: it does require doing some MAth stuff, but don't worry, it's easy.

Weak Points

• If implement in game, especially in Team Deathmatch, the ELO system doesn't care about your performance in the game, it just gives you a flat point based on the final result. If you played well and your team loses, sorry, the points are lost.

Note :

This is what I came up using my own research and I have no idea if Riot and Valve or any big game company could use the same thing as mine. They surely have their own system and we don't know the heck about it. 

This is a very basic ELO system and it may have errors (I'm not so good in Math :) ), I'm open to your comments and contributions. (And use it in your own risk)

OK, let's go

ELO Rating System for Team Deathmatch

Methodology

• Since ELO system is initially built for personal match, to use it for Team Deathmatch, we must assume two teams are two players, each with the ELO summed up from all teammates.
• If one team has bigger ELO points than the other team, the team is more likely to win. So if it's not, then it loses more points.
• The member with the most ELO Point in team will get smallest share in ELO points when team wins, and lose more points when the team loses.

Calculation

(this site provides the calculation of ELO system for chess, which I use for my method https://metinmediamath.wordpress.com/2013/11/27/how-to-calculate-the-elo-rating-including-example/)

Step 1 : Get current ELO Points for each team

Step 2 : %ELO Point of each team mate



Step 3 : Compute transformed ELO rating points of each team

           

r(1) and r(2) : current Elo points of each team.

Step 4: Compute the expected score of each team (E)



                                   
Step  5 : After the match is over, get the actual score





Step 6 : Get the updated ELO point of each team





r’(1) và r’(2) : updated Elo point of each team.

K -factor: K = 32

Step 7 :Get delta_r of each team


It's the difference between old and new ELO Point


Step 8 : Compute new ELO Point of each teammate

Multiply %r  of each member with the Dr, sort the result in ascending order

·         If the team lost: The member with the biggest %r will get subtracted the most point.

·         If the Team Won: The member with the biggest %r will get the smallest point..

Confused? Get this file and I'll illustrate the system in step by step

https://drive.google.com/open?id=0BzRDev8MAFcaZEp1bjlKWWNtWkE

Do you have any comment, please share with me.

Reference

https://support.riotgames.com/hc/en-us/articles/201752954-Matchmaking-Guide

http://dota2.gamepedia.com/Matchmaking_Rating

https://en.wikipedia.org/wiki/Elo_rating_system

https://metinmediamath.wordpress.com/2013/11/27/how-to-calculate-the-elo-rating-including-example/

https://steamcommunity.com/sharedfiles/filedetails/?id=312582297

http://steamcommunity.com/sharedfiles/filedetails/?id=260702087