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Pro Surfer Ratings Need a New Look: Part 2 – Evaluation of Final Rounds

Note: This article was originally written in 2017, before the ratings award system changed (for the better).

Last week I looked at a few cases showing possible issues with the WSL ratings system. Joel Parkinson won the championship in 2012 before winning a single event. And Mick Fanning and Julian Wilson both received only the second place value of 8,000 points at Jeffrey’s bay in 2015.

For this week, I introduce the notion of expected return for evaluating effectiveness of the distribution of ratings points for a given event.

Let’s see if consistency is over-rewarded in elimination rounds:

  • 1st and 3rd (16,500 total reward points) should be worth more than 2 2nds (16,000 total reward points)
  • 2nd and 5th (13,200 total reward points) should be worth more than 2 3rds (13,000 total reward points)

In both cases, I would not yet say that consistency is over-rewarded. But something interesting happens when you instead look at the records of surfers from 2 events after the Quarterfinals: 1st (3-0) 2nd (2-1) 3rd (1-1)  and 5th (0-1):

  • 1st and 3rd (4-1) vs two 2nds (4-2): This feels like too many points for 2 2nds.
  • 2nd and 5th (2-2) vs two 3rds (2-2): In this case the points awarded seems reasonable.

The first bullet feels like a problem. It feels like the point system inherently assumes that the event champion loses the very next round!  The truth is the opposite. He took all comers and get’s a consolation prize. This is where “consistency” is too highly awarded. Because you get too little points for being a champ.  But how many points should he get?

Again, the answer to that question is subjective.  But I think I’ve come up with a method to determine minimum.  I’ve adapted the financial concept of expected return (ER).  In this case, each surfer has an expected return from each round he enters, basically assuming he has a 50/50 shot of winning  a given round. This is a fair assumption given how close surfers are at the top.

Table 1: Expected Return of final rounds using current system.

Win Return (expected) Loss Total points Return from win Return from loss
Final 10,000 8,000 1,000 -1,000
Semifinal 9,000 6,500 1,250 -1,250
Quarterfinal 7,750 5,200 1,275 -1,275
Round 4/5 win 6,475

When you do things this way it starts to look a lot like gambling. At the beginning of the Quarterfinal all surfers have an expected return of 6,475 points. Then they each bet 1,275 points.  The losers keeps the remaining 5,200, and the winners move on to the semifinal, now with a 7,750 point ER each.  Then the semifinalists bet 1,250 points. The losers 6,500 points, but the winners get a 9,000 point ER.  Finally the two finalists bet only 1000 points!  If he wins he leaves the event with 10,000 points. If he loses he keeps his 8,000 points.

Thus – for the case that the finals were cancelled (as in the 2015 shark attack), both finalists SHOULD have received their expected return going in: 9,000 points, instead of the 8,000 points they did receive.

Again, this feels wrong.  You should increase your value by more as you defeat better opponents.  Each round should bet MORE points than the past, so the stakes get higher and higher.

Published in Sports Uncategorized


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