ITTF PTT rating system: answers to frequently asked questions

A new player becomes rated only after at least two winq against a player who are already on the rating list. The computer system at that time analyses all his/her recent results and calculates an appropriate initial rating.

This potential issue is covered by 2 rules:

1. The rating system has a depreciation mechanism which decreases player's points by 5% after 1 year of inactivity. We can adjust these 2 parameters to add more incentives to participate.
2. In order to be selected for World Championships or Paralympic Games, each player must have achieved a minimal tournament credit based on tournament ranking factors. For example, to be selected for London 2012, the credit value has been set at 80 (including regional championships) for the period from 4 November 2010 to 31 December 2011, this means up to 4 factor 20 tournaments, the regional championships + 1 Fa40; the regional championships + 2 Fa20, 2 Fa40, 1 Fa40 + 2 Fa20.

Because it's like comparing apples and oranges : singles and doubles are different. Being good in doubles does not necessarily mean that you are good in singles and the reverse is also true. This is a rating system to rate individual players.

Another reason is that in para table tennis, the difference in ability between 2 players can be significant especially when several classes are combined. This is even more obvious when looking at standing players where quick moves are necessary to hit the ball alternately.

Let's take the example of a class 10 player playing with a class 7 partner playing against another pair composed of 2 class 8 players. Now, let's say the class 10 player runs quickly enough to compensate his/her partner's more limited motion and they win, how should their rating evolve? Is it fair to say that the class 7 should half of the points or should he get less but then by how much?

This could be the case with the previous ranking system where a strong player could get points for winning against a weaker one. With the rating system, this is no longer the case.

Let me take a real example from Lignano 2011 in TM9: UKR vs. ESP. The Ukrainian team was much stronger than the Spanish team, a difference more than 500 points in ratings.

The results were as follows based on the rating system:

1. KUBOV,Vadym (2058) wins against Martín,Francisco Manuel (1434) 3:0 ; 4,5,4 -> no point
2. SHCHEPANSKIY,Yuriy (2120) wins against Azcón,Joaquín (1523) 3:0 ; 3,8,7 -> no point

Now let's say that Ukrainian team decides to play one more single by dropping the double (in reality they won the double 3:1 and later on the gold medal). The result on the rating system would be:

4. KUBOV,Vadym (2058) against Azcón,Joaquín (1523) -> no point

So there is no interest in losing the doubles. Players are clever and they will not play more games for nothing. Of course, one could argue that the difference between the 2 teams was too big but remember that if the difference is smaller it means that the risk to lose is higher.

It can happen that a players gets disqualified after having played a match, for example for failing racket control.
If the disqualified player lost the match, the ratings will move as usual.
If the disqualified player won the match, the result will be inverted and ratings will move accordingly.