I wrote yesterday about some observations from looking at WTN levels by NTRP level for women's doubles players, and key one being that the range of WTN levels for each NTRP level was quite large. After giving it some thought, I wanted to make a slight adjustment to what I did to perhaps be a little more fair to WTN.
My approach to the analysis was to look at players that had a 2021 year-end 'C' NTRP rating/level and look at the WTN's for these players. The idea was that if the USTA was able to give the player a 'C' rating, it should be good enough for WTN too.
Upon looking deeper, I found that a fair number of players I looked at did not have the blue check mark indicating a high confidence in their WTN rating, so it only seemed fair to take another pass at the analysis to only include those with a high confidence.
On to the new chart then!
For comparison, here is the previous chart.
The new chart does look better, the unexpected non-"normal" right half of the chart now looks better. So it would seem it was low-confidence players that were not rated accurately and causing the strange looking chart.
However, we see the counts at each WTN are down over 30%, so about half of the players that NTRP found had enough matches to get a 'C' rating, WTN does not give a high confidence rating. Now, this is in part because WTN calculates separate singles and doubles ratings so that shouldn't be ignored.
While the above few things are improved, the ranges of WTN levels for an NTRP level are still very large. At 4.0 for example, we still see significant numbers of players from 15 to 26 which is 12 levels, still more than I would have expected.
Standard deviations came down a bit but are still pretty large:
- 3.0 went from 3.1 to 2.9
- 3.5 went from 3.2 to 2.9
- 4.0 went from 3.3 to 3.0
- 4.5 went from 3.8 to 3.3
A small/modest improvement, but not a dramatic change.
So I thought it was only fair to use high confidence WTNs, but the observations don't change a whole lot.
What do you think?
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