Tuesday, May 06, 2008

Updated Arena Rating System

Back in 2006 I wrote a post on the Arena Rating System which still gets linked to all over the place. It's been driving me crazy that people might be reading a 2 year old post to get current information about the constantly changing arenas. I finally found the time and sat down and rewrote the post using the most current information I could find. I promise not to make a habit fo reposting.


Team Rating
The initial arena system was based on the ELO chess system where teams had a rating that changed depending on the toughness of their opponents. I'll leave the basic explanation of team ratings the same since they haven't changed that much. Team ratings are still primarly how arenas points are rewarded and how team's are matched up against each other. Players who have used holes in the arena system or switched between a lot of different teams will find that their personal rating is used instead of their team rating.

Lets have team A and team B who meet in the arenas. Team B has a moderately higher score then Team A which means their odds of winning are calculated as being higher for the match. This means that Team B's rating will decrease more if they lose and increase less if they win. Team A's rating on the other hand will do the opposite. There is also an arbitrary number in the formula which decides the maximize number of points lost or won for the match. I'm using the number 30 but honestly this number probably changes based on the rating difference between teams.

Team A's Current Score: 1500pt
Team A's Chance of Winning: 1500 / (1500 + 1580) = .48701

Team B's Current Score: 1580pt
Team B's Chance of Winning: 1580 / (1500 + 1580) = .51298

Now Lets say Team A won the battle then
Team A's New Score: 1500 + (30*(1-.48701)) = 1500 + 15.39 = 1516
Team B's New Score: 1580 + (30*(0-.51298)) = 1580 + -15.39 = 1566

Now Lets say Team B won the battle then
Team A's New Score: 1500 + (30*(0-.48701)) = 1500 + -14.61 = 1485
Team B's New Score: 1580 + (30*(1-.51298)) = 1580 + 14.61 = 1595

Personal Rating
Personal Rating works just like a seperate version of the Team Rating for each player who actually participated in the match. Blizzard put Personal Rating requirements on certain rewards because highly rated arena teams were selling spots to people who wanted to quickly gain points. Each player actually has a Personal Rating for each of the arena brackets in the game. Thus a person could have a very high 2v2 personal rating and an average one in the 3v3 and 5v5 brackets. If a player switches teams then their personal rating for that bracket is set back to 1500.

New rules for Season 4 (May 2008) actually use the personal rating for matching and point rewards over the team rating.

- If a character’s personal rating is more than 150 points below the team rating, they will earn points based on their personal rating instead of the team rating.
- If the average personal rating of the players queuing for a game is more than 150 points below the team’s rating, the team will be queued against an opponent matching or similar to the average personal rating.

Awarding Points
Blizzard has an arena calculator on their wowarmory.com website which can be used to tell how many points your team will earn with your current rating. Only teams that have played more then ten games that week will be awarded points. Also only players on that team that have participated in at least 30% of the matches will get points.

Exploits being Addressed in Season 4

Smurfing is the practice of creating smurf teams by taking a well equiped arena player and putting them on a team with a low rating. These players then artificially inflate the rating of the team and then switch back to their main team. They then use certain methods to make sure they play their smurf team which throws the match. The method works especially well in the 3v3 bracket which is easier to control the matching then the 2v2 bracket and doesn't require as many players as the 5v5 bracket. The new changes for awarding points based on personal rating will of course penalize teams that have players that frequently change teams.

Arena Scouting
Also Blizzard is making a change to arena scouting which is commonly used to make sure their opponents are a smurf team instead of a serious challenger. This method is also used in Win Trading where teams make aggreements to lose a match against a certain opponents. In general Arena Scouting is used at low population times when very few teams are in the queue. This allows arena teams to be fairly certain if both their queues pop at the same time that they are going to be matched together. If one team's queue pops before another then they re-queue.

- "If a team does not enter an arena match that is starting they will lose points equal to the amount that would have been deducted if they had played and lost."


Anonymous said...

The changes are promising but I do not see how this might combat the biggest concern I have in Arenas, which are mercenary teams where individuals "hire" highly rated players to play on their low ranked or newly formed to boost their ratings.

Im tired of constantly playing against 2200+ ranked players in my 1500-1600 bracket. Id like to play against teams that belong in the bracket I'm playing in.

Hopefully you can shed some light on whether these changes will address this issue in any way.

Relmstein said...

Unfortunately, I've found no information to suggest that the problem of "ringers" or hiring well geared players is being directly addressed.

Instead Blizzard thinks that most players will not want to hire out their services since switching teams will reset their personal rating to 1500. By the new rules when they switch back to their "main" team with a lower personal rating that's what they'll earn points by.

This might actually prevent the practice early in the season. But once the highly rated teams have earned all their gear they will probably start hiring themselves out again. This is going to be devasting since the rating requirements are going to keep Season 4 out of the hands of everyone except them.

Norzemen said...

I was surprised to learn that personal ratings will not persist through team changes, but on further thought I realized it was a moot point. So in S4 there will be rampant personal rating mercenaries who will be paid to PL players to higher PRs.

Heres how.

Me and my 5 friends who are all full S3 and have fully banked honor and arena points will dominate to 2k with in weeks of S4 opening. Then I simply join my War/Druid full S4 geared duo into your 3v3 team and PL you up.

It wouldn't matter if personal ratings persisted anyway because your personal rating is different in each bracket. There would have to be a single personal rating for all brackets that persists through team cahnges. Looks like point selling will diminish however and that is a good thing.

Relmstein said...

Quite frankly the only way to fix the arena system is to change the matching system to work on the item level of each person participating instead of any sort of rating that can be "exploited".

The original battleground matching system that was deactivated for making the queues too long was based on gear quality. It actively got the max ilevel item you ever had equipped in each slot and gave you an overall rating based on it.

The problem was that battlegrounds were really too large for the system and it increased queue times especially when one faction greatly outnumbered the other.

Jason said...

I am pleased that Blizzard is making these changes, even if some (like the personal ratings on all items) do come pretty late in the season, it shows that they understand what the issues are, and hopefully they will be addressed from season 1 at level 80.

Player power leveling is an issue, as others have listed before me, but the other large issue is the gear difference. In my 3's team, every time we go over a 1600 rating, we meet teams in full s3 (weapons and shoulders) who destroy us, and then gain 18 points from defeating us. I think that the gear matching would be an excellent start to combating this problem. While the shoulders don't mean much (other than the rating) the weapons, especially for melee take an annoyance (scrub warrior in s1 gear and a sword) to deadly (warrior with s3 mace)

The fact that caster's have not scaled as well as melee is also an issue I hope to see addressed in WotLK. If a warrior in full season 3 gets lucky with his executioner enchant, he is essentially doing 25%+ more damage (or more) to my priest because of the armor ignore.

While I know spells are not mitigated by armor, thanks to WotLK, all classes have more stamina than they did before, and smart teams start stacking spell resist at higher brackets because of how predictable the top teams will be. To combat this we have a few spell penetration items, but these items are useless if they don't have spell resist, unlike armor ignore which is always useful. I'd like to see casters, particularly spriests and other classes with low survivability, have some options for scaling better with melee in pvp.

Server: Aegwynn (US)

Kittenor said...

Nice write up, however your numbers are off. You're suggesting that a 240 point rating difference (at ~ 2000 rating mark) would be required to produce a result of 17 points.

In games between teams that are less than 100 points rating separation (ie both between 1900-2000), I'm seeing results that are 19 points and greater when the lower team wins.

Empirically, I believe the change in points is something closer to:
16 +/- [Team_Difference] / 50
Or in other words, for every point above 16 you get when you win a game, the opponent's rating was ~50 points away from you.

Anonymous said...

No Kittenor what he means is not that he is fighting 2k rated teams but that he is fighting people who were at one point 2k rated and have Full S3 gear. These people have either been boosted or have dropped their team, and rerolled to sell the team, points, rating whatever. Boosted players may not seem so bad because they are still lowly skilled scrubs, but you put that S3 Mace in the hands of an unskilled scrub and he becomes a killing machine because warriors take no skill to play and the S3 melee weapons are ridiculous.