Do we really want to score 3-0 wins differently from 3-2 wins?, For nerds only.

We can. It would be that great a change to the RC calculations. In addition there is much more computing power available today than there was 10 years ago so computer power and memory are not a problem anymore.

On a recent thread I initially thought it would be a great idea to score 3-0 wins higher than 3-1 wins. I did the math, it took me only a few minutes to get the shocking result and more time to pretty print it.

In short scoring 3-0 wins differently than 3-2 wins is something that I don't think most TT players would want or are ready for.
Below are calculations of the probability of winning games for best 3 out of 5. No big deal yet. The shocker occurs when one player is much better than the other. I start with the assumption that the best player will win 11 out of 12 matches. That is approximate difference of 138 ratings points which isn't much. From the probability of winning the match I can calculate probability of winning each game. Then I calculate the probability for
each win loss combination. Notice all the probabilities must add up to 1 and the probability of winning 3-0, 3-1 and 3-2 must add up to the probability of winning the match. This is my sanity check.

There are two ways of looking at this.
1. One is to multiply the probability of winning a game * games played . This is relatively simple.
For example compare a 3-5 win to the expected wins 5*p.game=3.85. . In this case the winner did not does well as expected. Should the winner actually have his ratings points go up or stay the same when he didn't perform up to the expected level for the ratings difference?
Another example. Compare a 3-0 win to the expected wins. 3*p.game=2.31 . In this case the higher player did slightly better than expected. Maybe he deserves more points than what the current RC system would provide.

2. The second method involves adding up the probabilities.
A 3-2 win involves adding up the probabilities for 0-3, 1-3, 2-3 and finally the 3-2 win. The sum is less that 0.5 which means the winner didn't do as well as expected and should maybe lose points.

Now when the ratings are much much closer to being equal the distribution of win combinations is closer to symmetrical binomial function and would work out much closer to the way people would expect.

Look at the chart below. The calculations are not too difficult.

The question I have is does anybody really care? People usually oppose change. That is clear to see. People usually don't like 'better' if they can't see why it is better for them.

I just thought I would but this 3-0 and 3-2 issue to sleep forever.

I think this puts this topic to rest.
Let the thread be dead.

David Marcus makes a good point about not using scores but here and in the other thread we were talking about games won and lost, not scores. If people wanted to score by games it is very possible. The mathematics/probabilities is not a problem. Computing power is not a problem. People don't need to see or understand the complications. It should be hidden from them.

The first reason I started this thread was I saw the possibility of better players losing points for not beating low players by a wide enough margin. It raises the importance of each game by a lot. I didn't think that would be accepted and it appears I was right.

The second reason was to show that the scoring would be much more complicated than saying winning 3-0 gets you all the points and 3-1 gets you 75% of the points. Hopefully this idea never comes up again.

The next reason is to keep people from trying to waste time "improving" RC.

Finally, ERT's thread had gone off the tracks.

I did learn something from reading the using scores link above. It is interesting that new players are supposed to be started with a rating of 1400 with a standard deviation of 450. I know for a fact that this has not be done where I play. Where I play the where started out with much lower scores and not so large a standard deviation. This brings the RC ratings of all the players down even though RC is not a zero sum rating system. It is still hard to get points if every one is rated 200-400 points too low.

I have always felt the RC ratings in my area were too low for a long time and now I know why. I could bitch but that would do me no good. I know my first coach would not play in RC events. He came from the NE with a regular RC rating. There were no points to win here because his RC rating was 200 points more than everybody else.

My point is that the RC rating system is really very good. Sometimes the people that run the tournaments and enter the data are not.

zeio said:

Here is the problem. Once you incorporate the games scored in the evaluation of ratings, you need to answer the question why not the points scored as well?
Is the latter any less important, given the former is the direct consequence of the latter?

Click to expand...

In theory you are right but David Marcus makes a good case against. I don't like the fact that each net ball or edge ball affects ratings.

The effect would be that people would fight for every point even if they know they have lost. This could be a good thing.

Consider the 3 semifinal encounters between Wang Hao and Ma Long in the WTTC in 2009, 2011, and 2013. The scores were as follows:

Games(Points), Total Points/Difference
2009 - 4:1(10, 8, -10, 9, 9), 55:48/7
2011 - 4:2(7, -9, -7, 10, 7, 9), 61:55/6
2013 - 4:2(9, 7, 3, -7, -12, 3), 63:47/16

The match in 2011 proved to be the closest, followed by the one in 2009, and lastly the one in 2013. The total points scored is more or less in line with that observation. However, the same game score of 4:2 in 2011 and 2013 didn't reflect the striking difference in intensity at all. ML led 2:1 in games before dropping the next 3 in 2011. WH led 3:0 in games before dropping the next 2, then ML gave up in the 6th in 2013. Would you rate both players the same way in both matches just because the game score happened to be the same?

Click to expand...

Or it could be a bad thing.

Like I said in ERT's thread, I don't have a bone in this fight. I only want to make it clear what the consequence are of using games won and lost to adjust the scoring. Now you bring up points won or lost. There are consequences to that too.

I have tables for scoring by points too. Now what? Ratings adjustments by points won and lost would effectively eliminate the need to play games to 11. Just play to whomever gets to 33 points first or go back to winning 42 points ( 2/3 games to 21 ). People with weird styles would like that because they could get an early lead while the opponent adjusted. As it stands now you can afford the lose the first game without a penalty except being behind by a game in the match.

Again, I just want to show the consequences of taking games won or lost.
So far it seem most people are against using games won or lost to affect the ratings.

So the question zeio asks is if adjusting ratings by point won or lost is even better would you like the change?
My vote is I don't care.
What do others say about adjusting ratings by points won or lost?