Take the 2-minute tour ×
Sports Stack Exchange is a question and answer site for participants in team and individual sport activities. It's 100% free, no registration required.

I am going to run/administer a table tennis ladder in the department and have been reading a bit on different ladder systems. I have read the suggestions on a relevant question but, with all due respect, I can't say I am happy with either answer. I feel like swapping is too extreme where as ELO would be too convoluted for this level, not to mention too much of a pain for me to keep tabs.

I came across ladder rules from a casual table tennis club and decided to modify them a bit. Came up with the following concept, but I am not sure if it is fair. Any help is warmly welcome at this point.

Proposed rules:

  1. All players start with 100 points (due to no prior ranking of players)
  2. Matches are played as challenges, thus can occur asynch
  3. There are three possible cases for the matches with regards to winner (W) and loser (L)

    • If (W) has 50% or more points than (L) --> (W) gets 20p and (L) gets 10p. Example scenario: Player A has 200p and wins over Player B who has 100p. New points would be 220p for A and 110 for B.

    • If (W) has 50% or less points than (L) --> (W) gets delta/2 points, whereas (L) loses delta/2 points [delta = point diff between players prior to the match] Example scenario: Player A has 100p and wins over Player B who has 200p. New points would be 150p for A and 150 for B.

    • If (W) and (L) are within 50% in points to one another --> (W) gets 30p and (L) gets 10p. Example scenario1: Player A has 100p and wins over Player B who has 80p. New points would be 130p for A and 90 for B. Example scenario2: Player B wins over Player A (with the same points as Ex1), then new points would be 110p for A and 110p for B.

The idea here is to give incitement for playing more games, so losing to a better player is not all that bad. I have made up the numbers a bit ad-hoc though so I am not sure if it would be fair in the long run.


Edit1: example scenarios given for three cases.

share|improve this question
    
have no knowledge of table teniis but: "has 50% or more", "has 50% or less". what happens if it is exactly 50% ? the easiest thing to do would be create 4 or 5 random players, and play out a few games (toss a coin for the winner) and see how the league stacks up. questions i would ask is if there is enough incentive for the table leader to accept any challenges from lower players and conversely would lower placed players only ever challenge top places in the table. –  TheCellarRoom Sep 25 '12 at 10:59
    
... you also say if W and L are within 50% of points, how are you calculating this, L is within 50% of the winners score or W is less than 50% ahead of L's score. -- just some thoughts –  TheCellarRoom Sep 25 '12 at 11:01
1  
I am not sure why exactly 50% should be a problem... I wrote down some example scenarios to reflect the idea. Please let me know if I have misunderstood your comment. –  posdef Sep 25 '12 at 11:31
    
as for the incentives, one can enforce the acceptance of challenges, given that the dates are flexible. In other words player are not allowed to ignore challenges. –  posdef Sep 25 '12 at 11:33
    
In my opinion, anything that shies away from the official rules is not fair. Although you did say this was happening in a department? So I'm guessing you mean at work? If that's the case and/or you are just playing for fun and not serious competition, I don't see a problem with tweaking the rules a bit. –  Zack Sep 25 '12 at 12:02

3 Answers 3

up vote 4 down vote accepted

Since this is your custom tournament and the participants are your friends, you can afford to experiment with the rules.

My suggestion would be to start off with this, and whenever you find it biased in some way, just make a few rules changes and proceed. Without having a trial run, you will not be able to find out the drawbacks, and you may also find that the frequency of participation will require you to change the values of the system to give everyone a fair chance.

One thing that I would like to point out is that you will need additional rules to accommodate a participant who joins the tournament after it had started. With that in place, give this system a run and see how it goes.

share|improve this answer
    
any suggestions on how to handle a late entry? –  posdef Sep 25 '12 at 16:29
    
Anyone joining late can challenge any three players. His/her points can be equal to the points of the best player among the 3 whom he/she has beaten. If they lose all three, their points is equal to the last ranked player. These three matches do not affect the points of the players. This is a suggestion. Feel free to improvise. –  Max Sep 25 '12 at 16:39

Why not using a well-know ranking system such as Elo to be fair? I know this website implement it:

http://tt.laddera.com

It evaluates players skill based on Elo rating system but you can customize your ladder to fit your need.

share|improve this answer
    
He already ruled that out, what's the point of just saying "use it"? It looks like you didn't notice he did. Otherwise you could have said "I know you ruled it out, but I think it would be a good idea anyway, because of reasons". –  Lohoris Oct 19 '13 at 14:43
    
@Lohoris posdef thinks keeping track of ELO is too time-consuming. A website that does the complicated calculation would be fine. –  Bernhard Oct 20 '13 at 14:31

I don't understand it, maybe it's good but as you explain it (even with examples) it's too convoluted.

  • Why do you have fixed points in some occasions and % points in others? It would make much sense instead to have always a theoretical % in all cases, with some caps (like always %, but no more than 20 total).

  • In 3.a and 3.c both players gain points, while in 3.b W wins points and L loses points? Did I get it right?

  • Is there some cap on how many matches can a player play? Otherwise I can just play, like, all day, and farm up points. Similarily you should somehow bar two players from playing against each other too many times (not banning it, but giving a negative feedback such as reduced points).

I'm totally unconvinced (disclaimer: I hate ELO-like systems anyway), and I'd suggest you to completely switch to a system which I cosider fairer and that's objectively simple:

  1. keep track of all "pairs" of player, i.e. make a table with all players in rows and columns

  2. every time W beats L, W gets "one point against L" (Andy beats Beatrix, so the virtual match "Andy vs. Beatrix" is "1-0")

  3. everyone is required to play at least twice against everyone else (if this isn't practical, workarounds can be designed)

  4. at the end of the competition, consider each pair of players as a virtual match, and assign them points based on that (2 points for win, 1 for draw, 0 for loss)

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.