New Elo Ranking System for Tennis Ladders

Hi Trevor,
This new feature is great. I have a few questions though.

1. I wrote a program that uses Canada's Rogers ELO Rating but using my own table for gains/loss and we also started with initial rating of 1600, 1550 and 1500 for our Level 3.0, 2,5 and 2.0 level players and I've entered all our tournament and ladder matches from last year so we have an up to date ratings. Is it possible to manually enter them in Ladder?

2. Can we use this rating system instead of the Registered Level in tournaments? If not, maybe you can incorporate this in future site upgrade where the player has the option to enter a rating (1500, 1550, etc) aside from the Player Level?

Thanks.

I'll wait for the day when we can use this as the official ranking system instead of the Player Level. I'm assuming that for this to happen. we'll have to change the registered player level from the current 2.0, 2.5, 3.0 etc to ratings 1500, 1450, 1400 and so on.

Thanks for the prompt reply. Trying to satisfy my curiosity, I applied the ELO on our last year's Ladder and recalculated all players ratings. Here's one match that I want to clarify.

Dennis Aldon 6 10 10 1484 1496 - gained 12
Ray Armada 4 18 18 765 759 - lost 6

Based on the above numbers, the Rogers ELO calculations would have
Dennis gain 6 if he wins, Ray loses 6 points.
Ray gains 12 points if he wins, Dennis loses 12 points.

Since Dennis is the higher rated player, his lost points should be greater than his won points.

And depending on the gain/lost points table, that BIG rating points difference may have earned Dennis ZERO points if he wins and Ray ZERO point lost.

Trevor Meier wrote: You can always change a team's points on your tennis ladders. So if you wanted all your 2.5 players to start the ladder at 1450 points, you could do that.

I was able to change the points but it didn't recalculate with the already played match. It assigned it as the new ladder points.

Before the change:
Carlos Buencamino 8 1 1 1500 1516
Nandi Nacu 0 1 3 1500 1484

After the change
Nandi Nacu Points Change Tooltip 3 4 1484 1400

4 Nandi Nacu Wins: 0
1400 Level: 2.00 Losses: 1

Or will it recalculate it tonight?

Thanks.

Hi Trevor,

I'm glad you have been working on an improved ranking system. Something seems a bit amiss however, at least in the early going. I converted our completed ladder ( www.globaltennisnetwork.com/network/tenn...dder-end-jan-31-2016 ) to the new ELO system and noticed the following for our first three matches:

Match 3
Daniel / Ted 6 1920 / 1080 2120 / 1280
Deb / Rob 2 1920 / 1080 1720 / 880

Match 2
Daniel / Deb 6 1484 / 1484 1920 / 1920
Rob / Ted 4 1516 / 1516 1080 / 1080

Match 1
Rob / Ted 6 1500 / 1500 1516 / 1516
Daniel / Deb 0 1500 / 1500 1484 / 1484

What you'll see is:
- that there was very little points movement (16 points) after the first match - fine
- the second match (which is a repeat of the first match) has a monstrous swing in points (436 points). Why?
- So after the 2nd match, even though everybody was 1-1, there was now a significant differential in points between the players (seems very strange and doesn't reflect reality very much). In addition, the team that lost by a closer score (6-4) now has lower points than the team that got skunked (6-0). Seems unfair.
- We switched up teams for the third match and you'll note that Ted, even though his record is 2-1, has significantly fewer points (440) than Deb, even though Deb is 1-2. Deb, who shares the same 1-2 record as Robert has 840 points more than Rob.

thanks for all your work on this site. I so appreciate it.
ted