Wednesday, October 9, 2019

Simulating 2019 USTA League Nationals - 40 & Over 4.0 Women

As I did last year, I will be doing simulations of each Nationals to predict who the most likely four teams are to make the semi-finals, and also look at other interesting things that may occur.  Last year, the simulations did a pretty good job predicting who would advance to the semis including having all four teams predicted correctly several times.

Why do these simulations you ask?  The primary reason is that the format for USTA League Nationals is now a flight-less random round-robin where each team plays four other random opponents.  This introduces significant variations in schedule strength, the possibility of an undefeated team not making the top-4, and teams vying for the top-4 perhaps not having played head-to-head and unfortunate tie-breakers being used.  The simulations aim to educate folks on how it all works and look at what may happen.  Also see this write-up for some things to know about Nationals.

Nationals are approaching the second weekend of competition, the 40 & Over 4.0 women's event being held in Surprise, AZ.  Here is what the simulation says is likely to happen.

As a reminder, my simulations are done using my Estimated Dynamic NTRP Ratings and looking at the average rating for the top group of players on each team, the actual schedule each team will play, and then doing a million simulations of the matches with some random variation in each team's expected result.

First, with 17 teams playing a random four opponents, it will always be possible for there to be five (or more) undefeated teams.  It is possible to limit it to five with the right schedule, but the USTA did not do that this time around and 52 of the million simulations had six teams undefeated.  The chances of five is just 0.5% and four is just a modest 9%.

Four undefeated would be a nice and tidy result with no drama, but there is a 50% chance of just three so we are more than likely to have some tie-break scenarios.

That leaves a good chance, 87%, that there will be a tie for the last spot and it come down to tie-breakers.  That tie is likely at a 3-1 record.  The most likely size of the tie is three at 32%, but four has a 30% chance, five 17%, and two 15%.  The chances of larger ties diminish pretty quickly, but a 11-way tie is theoretically possible, but it appears a multi-way tie is a very high probability and it could be reasonably large.

Should there be a tie on team record, it comes down first to who has the best court record, then head-to-head (if applicable), then to who lost the fewest sets, then who lost the fewest games, and finally percent of games won.  There is a 20% chance it comes down to the sets lost tie-breaker, and there is a 80% chance that is between two teams and a 19% chance it is between three teams,  If the controversial tie-breakers are going to come into play, this is the likely spot.

The schedule strengths do vary a bit but not too much, the team with the easiest schedule having an opponent average of 3.96 while the team with the toughest schedule having an opponent average of 4.07.  This leads to an easier road for some teams than others, in the strongest team has the second easiest schedule.

So who is most likely to come out in the top-4?  Southwest, Intermountain, Middle States, and Texas head the list, Southwest the most likely to make it and the favorite to win it all.  Eastern, Southern, and Mid-Atlantic are ready to step in if anyone slips up.

For those interested, I offer a variety of reports to make Nationals more fun and help captains prepare.  I have a Simulation Report that has all of the details of the simulation including the average ratings for each team, each team's schedule strength, the most likely record for each team, and the chance of each possible record for each team.  I also offer reports to help teams scout opponents in more detail, both a Flight Report with full roster averages, top-8 averages and played by court averages for each team, as well as full Team Reports with detailed ratings for each rostered player and stats who who plays with who and on which court and how they do together.  Contact me if interested in any of these reports.


  1. You have 18+ instead of 40+ in your title, had me a little confused. Was your simulation for 40+ still?