Match Maker – Phase 3 – Update
Phase 3 incorporates a variation of Elo and is undergoing testing against the telemetry data the servers have been providing us. Below is how Elo calculations are being processed and giving us an indication of how Match Making Phase 3 will match players of relatively even skill against one another.
In Figure 1, you will notice the highest score a player can have is 2800. The lowest score a player can have is 0. When a player first starts playing MWO, they are assigned an Elo score of 1,300.
The maximum amount a player’s score can change in a single match is ±50.
One of the key calculations that needs to be done is to determine the probability of a lower ranked player beating a higher ranked player.
An example of this is, if two players of the same ranking have a 50% chance of winning each. The bigger the gap between the two player’s scores, the less probability of the lower score player beating the higher scored player.
A player’s new rating, after a match is complete, is calculated using the probability value determined in Figure 1’s formula. In Figure 2, we take a look at a sample of how a player’s score changes between matches.
In the example, one player has a rating of 1,350. Another player has a rating of 1,410.
The first step is to calculate the probability of the 1,350 rated player beating the 1,410 rated player. The rating difference between the two players is found by subtracting the lower player score from the higher player score. In this case it’s 1410 – 1350. There is a difference of 60 points between the two players.
Filling in the formula from Figure 1, we find that the 1,350 rated player has a 0.41 probability of winning (or 41% chance). This is where Elo starts to determine the outcome of a match and the result of player scores after the match is complete.
We now use the probability value of 0.41 to determine the change in player ratings.
Case 1: 1350 Player WINS over 1410 Player
Since the lower rated player won despite the odds against him/her, they are rewarded a much higher change in score than the higher player is. The higher player score will actually be reduced.
One variable that is set by winning or losing is the WinFlag (as seen in Figure 3). The WinFlag is a binary (true/false) value of either 1 (Player has won) or 0 (Player has lost). In this case, the WinFlag value is 1.
Let’s begin the calculation:
Old Rating = 1350
Maximum Change Allowed = +50 for a win, -50 for a loss (as seen in Figure 1)
WinFlag = 1
Probability of Winning = 0.41
1350 Players new ranking = 1350 + 50 x (1 – 0.41)
1410 Players new ranking = 1410 – 50 x (1 – 0.41)
A player’s rating will only go down if they are beaten by a player who has a lower rating than theirs. In this case, if the 1350 player lost, their score would not change since the Match Maker was correct in its prediction.
So how does this affect Match Making – Phase 3?
This formula and scoring system is run against match data that the current dedicated servers are giving us. Basically it’s being tested on real world numbers generated by you, the community.
Once we get a full understanding of how accurately the Match Maker is working, we are going to add some additional parameters to the mix. These include a more defined player skill rating and a Mech weight class balancing system. More info on these when the first pass of Elo testing is done.