Thursday, July 27, 2023

Has the ITF updated the WTN algorithm? Is it any better?

I received an e-mail today from the USTA titled "Now Here: Updates to ITF World Tennis Number" and it goes on to describe the ITF on-boarding several new federations, but also says the ITF has taken the opportunity to "enhance the ITF WTN calculation" and as a result player's WTNs may change.

I've written about the WTN before (see a list of all WTN related posts here) and done some analysis (men's singles, women's singles, men's doubles, women's doubles) that raised some questions about its accuracy.  Since then, I haven't written that often as 1) the ITF/USTA have made it difficult to gather data to do analysis and 2) casual monitoring showed the same initial observations still stood.  This new announcement may cause me to revisit things, although it may be hard to do so broadly.

An initial/personal look though reveals there have been some big changes!

I'd had a WTNs of around 13 forever based on singles play from years ago, and checking today, I see my WTNs is now 26.9!  I'd say that is a change.

In doubles, I've been around a 22 WTNd and today, 29.2!

Whoa, overnight I've gotten a lot worse!

For reference, I'm a middling 4.5 playing primarily (only lately) doubles with a few wins in men's this year but more losses, although several were in match tie-breaks.  Even if NTRP were to bump me down to 4.0 at year-end, the new WTN algorithm seems to be saying that I as a 4.0/4.5 male is a 26.9 WTNd.

If this is done across the board and it is consistent, perhaps it is better, relatively at least, but on the surface the mapping between NTRP and WTN seems even worse than before now.  A 4.5 male at 26.9 doesn't leave a lot of room for the 2.5-4.0 players, and there is a lot of room for the 4.5-7.0 players.

Looking at some players around me, I've recently been playing 8.0 mixed with 3.5 women partners, and have done better (4-1 this season) and WTNd had my partners similarly rated to me, around 21-24.  That screams that something is wrong with the gender neutral part of WTN, and this algorithm change as my 3.5 women partners are still similarly rated to me, 28-32 or so.

I'm sure there will be naysayers out there who say I must be playing like a 3.5 woman, perhaps that is true, but then the folks I've beat must be at that level or worse.

So there seems to have been a blanket shift up numerically (down in rating strength as WTN has 1 as the best and 40 as the worst) to give more room for high rated players, but no significant change to making gender neutral relativity more accurate.

I'll try to do some more analysis later, but what are you seeing?  What do you think?  Is WTN even something relevant to you in any way at this point?

7 comments:

  1. In my anecdotal experience - WTN is pretty worthless. I have beaten by bagel/donut scores a couple of guys ranked quite a bit better than me on WTN. Even after winning those matches, our relative rankings barely budge. Both tennisrecord and UTR are much better assessment of who I am likely to beat or lose to. I am a middling 3.5 male.

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  2. I thought this article was very interesting. I have been an 9 in doubles (I don’t really play singles ever) and jumped to a 20 in doubles. I am a high 4.5 female that goes from 4.5 to 5.0 and back down frequently. I don’t think the WTN seems to be accurate enough.

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    1. Thanks for the feedback. A change of +11 is awfully big, but a 4.5/5.0 female at a 9 doesn't leave a lot of room for college and pro women in the 1-8 range let alone male players. So 20 _may_ be more appropriate, I guess we'll wait and see how things play out.

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    2. Totally agree. I always wondered how accurate 9 was. I thought at first it was ridiculous. Agree 20 would be a better number. Personally I don’t understand WTN well enough to balk at anything, lol. I guess as long as I end the year 4.5 I’ll be pretty happy 😂 But I’m interested to see how that would relate to league players and recreational players going forward. We know the NTRP system so well, I wonder what WTN will truly bring to the table.

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    3. I think WTN is primarily the ITF/USTA/LTA's attempt at heading off UTR, meaning the focus is on junior and college players and to some degree pros. I think there is limited usefulness to league players, at this point at least.

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    4. Thanks! Makes total sense!

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