Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

World Rugby Rankings

  • 29-11-2014 5:16pm
    #1
    Clauric
    Registered Users, Registered Users 2 Posts: 610 ✭✭✭


    I'm trying to replicate the calculations for the World Rugby rankings. However, the formulae are not exactly readily available.

    The IRB's (sorry, World Rugby) website does not really give a good idea of how the rankings work, and doesn't give any formulae. I did find a formula in the French Wikipedia article about the subject, but it is not really satisfactory either.

    From what I can gather, the formula is:
    • If a higher ranked team wins it gets C x (1 - D / 10); the lower ranked team loses the same amount.
    • If a lower ranked team wins, it get C x (1 + D / 10); the higher ranked team loses the same.
    Where:
    • C = 1, 1.5, 2 or 3 depending on whether the the team wins by more or less than 15 points, and whether the match is a World Cup match or not.
    • D = Team's world rankings - team's opponent's world rankings + 0/3 points based on whether the team is away or home, with a max/min of 10/-10

    This all seems reasonably straight forward. However, I can't work out what happens if the teams are tied in points before starting the match. Who does the system view as being the higher ranked team?


Comments

  • #2
    cython
    Registered Users, Registered Users 2 Posts: 4,792 ✭✭✭cython


    Clauric wrote: »
    I'm trying to replicate the calculations for the World Rugby rankings. However, the formulae are not exactly readily available.

    The IRB's (sorry, World Rugby) website does not really give a good idea of how the rankings work, and doesn't give any formulae. I did find a formula in the French Wikipedia article about the subject, but it is not really satisfactory either.

    From what I can gather, the formula is:
    • If a higher ranked team wins it gets C x (1 - D / 10); the lower ranked team loses the same amount.
    • If a lower ranked team wins, it get C x (1 + D / 10); the higher ranked team loses the same.
    Where:
    • C = 1, 1.5, 2 or 3 depending on whether the the team wins by more or less than 15 points, and whether the match is a World Cup match or not.
    • D = Team's world rankings - team's opponent's world rankings + 0/3 points based on whether the team is away or home, with a max/min of 10/-10

    This all seems reasonably straight forward. However, I can't work out what happens if the teams are tied in points before starting the match. Who does the system view as being the higher ranked team?

    I'd say it's probably a remote enough possibility for teams to be on the exact same points to 2 decimal places to be joint in the rankings, but I would guess they would cancel each other out in the section below in that the bolded would be 0:
    D = Team's world rankings - team's opponent's world rankings + 0/3 points based on whether the team is away or home, with a max/min of 10/-10
    So it doesn't matter if D is added or subtracted since it's 0? In essence, a 3rd point to yours above
    • If the teams are equally ranked wins, the winning team gets C ; the losing team loses the same.


  • #3
    Clauric
    Registered Users, Registered Users 2 Posts: 610 ✭✭✭Clauric


    cython wrote: »
    So it doesn't matter if D is added or subtracted since it's 0?

    If 2 teams are on 30 points, the home team is playing for 1+/- 0.3 points, while the away team is playing for 1 point, assuming that neither teams wins by more than 15 points, and it is not a World Cup match


  • #4
    cython
    Registered Users, Registered Users 2 Posts: 4,792 ✭✭✭cython


    Clauric wrote: »
    If 2 teams are on 30 points, the home team is playing for 1+/- 0.3 points, while the away team is playing for 1 point, assuming that neither teams wins by more than 15 points, and it is not a World Cup match

    Ah, sorry, misread that piece in my one. I'm not sure so, but you could try some experimentation in this calculator to see how he handles it? I think this is a long standing one, and has been tested quite a bit. Again though, this might be a sufficiently unlikely scenario not to have been tested there either.


  • #5
    Clauric
    Registered Users, Registered Users 2 Posts: 610 ✭✭✭Clauric


    cython wrote: »
    Ah, sorry, misread that piece in my one. I'm not sure so, but you could try some experimentation in this calculator to see how he handles it? I think this is a long standing one, and has been tested quite a bit. Again though, this might be a sufficiently unlikely scenario not to have been tested there either.

    Interesting website, where I originally found the French wikipedia article.

    His website seems to assign the 1 + 0.3 points to both teams depending if they win or lose, even in a neutral ground, which I don't think is right.


Advertisement