The ratings system

Discuss Crisis in Command Volume II: Drive on Moscow. Designed by Ted Raicer
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s_nkarp
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The ratings system

Post by s_nkarp »

Several people have inquired how ratings are calculated. We use a pretty standard methodology called "Elo" (after the inventor) that uses two parameters:

The F-factor (“rating disparity” or “skill gap") of 400 is the score range at which chance of winning rises by an order of magnitude. For example, a 1600 player has theoretical 2x chance of beating a 1200 player. This factor is less useful to adjust - a larger F-factor will merely “spread the rankings out” further (think larger standard deviation), but with not change the order in which players are ranked. The leading chess ranking systems all seem to agree on an F-factor of 400.

The K-factor of 32 is the maximum a player’s rating can shift as a result of a single game. A larger K-factor means that players can find their true range faster, but that scores place higher emphasis on recent events (versus longer historical performance). The USCF uses a tiered K-factor system, applying 32 to players under 2100, 24 to players under 2400, and 16 for players above 2400. FIDE uses a similar 30/15/10.

Sources:
Overview: http://en.wikipedia.org/wiki/Elo_rating_system
K-Factor: http://en.wikipedia.org/wiki/Elo_rating ... e_K-factor
F-Factor: http://en.wikipedia.org/wiki/Elo_rating ... al_details (see Para. 7)
F-Factor: http://www.chess-mind.com/en/elo-system#formule (see factor breakdown)
Eldnas
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Re: The ratings system

Post by Eldnas »

I'm enjoying your game head to head thru Game Center. I've noticed the following things about the ratings system:

After finishing my first 4 games of the Typhoon scenario and losing 3 with one win, my rating went down below 1500. The next morning my rating was above 1500 and it showed I'd played 10 games and won 6 of them.

I've noticed a further oddness with the rating system. Just finished a game with a fellow Qt3 player that ended on my turn as the Soviets. I passed on my last turn and the game ended in a draw with 14 VPs. I closed the draw window, but the game did not clear my Game Center icon showing I still had a turn to make in this game. I restarted the game and it replayed the turn and showed the draw screen again. I closed the draw screen again and the icon still remained showing my turn in Game Center. I did this twice more. Each time I did this my rating went down by 16 (I think) and my total draws (in the game under extras, Gameplay Statistics, Show) went up from 0 to 4.

I went to the iOS Settings app, picked the game and turned the Restore State to Off. This stopped the problem.
daviddunham
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Re: The ratings system

Post by daviddunham »

Unfortunately, there are some issues with end-of-game tracking (since Game Center doesn’t let you track on behalf of your opponent). We are currently testing a fix for at least one of them.
Jarling
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Re: The ratings system

Post by Jarling »

If you look at the rating leaderboard, all ratings (after the initial 1500 is subtracted) are divisible by 16.

If the ELO works right, the only way this could have happened is if absolute all games have been played between players of exactly the same rating. I don't think this is the case so something must be wrong.

Examples on how the ELO should work (with the parameters you've listed):

Let's say Players A and B play a few games:

Player A - Old rating 1516 - win - new rating 1531
Player B - Old rating 1500 - lose - new rating 1485

Player A - Old rating 1531 - win - new rating 1545
Player B - Old rating 1485 - lose - new rating 1471

Player A - Old rating 1545 - lose - new rating 1526
Player B - Old rating 1471 - win - new rating 1490

So; are there any known issues with the ratings, except that resigned gamed doesn't seem to be registered?
thedudeabidez
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Re: The ratings system

Post by thedudeabidez »

I've got a game where it was an Axis Victory, Moscow taken, and the Victory screen flashed up, but the game is still showing up in the "Opponent's Turn" column and I can't clear it or receive Rating points for the win. Any advice? It even says "Axis Victory" in the "Opponent's Turn" Game Details section but it's stuck there....

Note that it is impossible to send a screenshot and report a bug once the Victory screen has appeared....
daviddunham
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Re: The ratings system

Post by daviddunham »

Opponent's Turn is correct, in that Game Center needs to pass them the game so they can see the defeat.

We are working on some fixes for tracking victory (it can depend on which player moves last).
Tigre
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Re: The ratings system

Post by Tigre »

thedudeabidez wrote:I've got a game where it was an Axis Victory, Moscow taken, and the Victory screen flashed up, but the game is still showing up in the "Opponent's Turn" column and I can't clear it or receive Rating points for the win. Any advice? It even says "Axis Victory" in the "Opponent's Turn" Game Details section but it's stuck there....

Note that it is impossible to send a screenshot and report a bug once the Victory screen has appeared....
Same is hapening to me, also I got 16 pts for the win but my openent did not loose anything, because the game is stuck on my pad !? To skip the victory screen I can go on the rewiew mode and manage to press the continue, still the victory screen pops Up and the game is still stuck in the queue ..
marc9600
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Re: The ratings system

Post by marc9600 »

Two wins (both cases the other player resigned) and one draw so far. The draw was against a player who has two wins and two draws (includes the game against me). Why has my rating dropped to 1,484 ?
thedudeabidez
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Re: The ratings system

Post by thedudeabidez »

Hey Dave,

Here's an example that's really easy for everyone at Shenandoah to investigate.

The game of Typhoon we just played resulted in an Axis win -- just barely, good game! -- but go into Main Menu - Play - Choose and in the Completed Games column instead of "Axis Victory" it says "Turn 5, Soviets to move". Also my Rating did not change for the win. I do know the game engine recognised it as an Axis victory because the victory screen flashed at the end of it. But it didn't register as a victory in the ratings/gamed details for some reason.

Also, this may be connected to the last move bug described above. You made a final move that ended the game but I had to send you a couple of chat messages asking before it finally showed up. A couple of other players have mentioned that the last move of the game doesn't always go through until the player who made the last move goes back and watches it again thru to the game-end victory/defeat screen.

Anyway, hope you can find the solution. At this point only my defeats seem to registering in the ratings ;-)

Gio
thedudeabidez
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Re: The ratings system

Post by thedudeabidez »

Actually, this seems to have happened before too. Below is a photo of my "Games Completed" column; you'll note that there is one game listed as "Axis to Move" -- not "Axis Victory" -- despite being in the Completed column. I played the Axis in that game (full campaign), I won with 26 points, saw the Victory screen flash, and yet no win registered. This is more than a little frustrating since I played the same opponent twice, and when he beat me in the next game, I lost Ratings points for it.

Clearly the Ratings system is broken/buggy; wouldn't it be better to disable it until its fixed?
s_nkarp
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Re: The ratings system

Post by s_nkarp »

thedudeabidez wrote:Clearly the Ratings system is broken/buggy; wouldn't it be better to disable it until its fixed?
No way to disable it remotely -- we do have a fix, which will be be released with others before Xmas. Unlike (for example) a Facebook app, every update has to be reviewed by Apple -- frustrating as it is, there's no way to roll out changes piecemeal.
thedudeabidez
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Re: The ratings system

Post by thedudeabidez »

Well, glad to hear there's a fix at least. I've won twice as many as I've lost yet am only at 1516. Two wins went unrecorded while all the losses registered just fine :x
sa_gibson
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Re: The ratings system

Post by sa_gibson »

Call me crazy, but I'd scrap the rating system entirely, and not replace it at all. It seems to generate a lot of obsession about one's own rating combined with debate about how it works leading to suggestions about how it ought to work. I don't see anything it actually adds to the game. Just play!
Dugrim
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Re: The ratings system

Post by Dugrim »

sa_gibson wrote:Call me crazy, but I'd scrap the rating system entirely, and not replace it at all. It seems to generate a lot of obsession about one's own rating combined with debate about how it works leading to suggestions about how it ought to work. I don't see anything it actually adds to the game. Just play!
I totally agree.
This is not chess, nor a competitive league.
ELO or other rating systems in casual games are a terrible choice, in my opinion.
Steiner7
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Re: The ratings system

Post by Steiner7 »

I agree with Scott Gibson. Even if the Elo was functional, I dont see what use it is. In chess, for example,there are so many games on offer you can always get paired with someone of equal ranking. Here, you take whatever is on offer.

In any case,as it is now, the elo system is only getting people annoyed. Personally I have won seven lost three and I am showing a 3 to 2 loss ratio. Furthermore some great Bob players I know are showing loss ratios.

I realize its not important in essence, but I think it rubs off negatively insofar as what we humans think is fair or not...
thedudeabidez
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Re: The ratings system

Post by thedudeabidez »

> Personally I have won seven lost three and I am showing a 3 to 2 loss ratio.

Same here. I'm 10-3 and but showing up as 6-3.

It seems like any game where the opponent resigns does not register as a win for me, or a loss for him.
But that doesn't explain all the missing data; some games were played through to the end but didn't register as victory or defeat.
Frustrating, as you have to really work for a win in this game!
thedudeabidez
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Re: The ratings system

Post by thedudeabidez »

Yeah, just won another game of Typhoon, opponent resigned, no shift in Rating. Resign is clearly not working.
daviddunham
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Re: The ratings system

Post by daviddunham »

As we have said, there are several ratings bugs, which will be fixed in an upcoming update.
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