Simulating 2019 USTA League Nationals - 18 & Over 5.0+ 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 get started just four days from the writing of this preview, the 18 & Over 5.0+ women's event being held in Las Vegas.  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 15 teams playing a random four opponents, it should be possible to avoid more than four undefeated teams from occurring and thankfully the USTA got it right.  And there is just a 1.4% chance of four teams being undefeated which is quite low.

In fact, there is only an 18% chance of three teams being undefeated, so we are likely in-line for some serious tie-break scenarios.

That leaves a very good chance, 92%, 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 four at 28%, but three and five way ties are likely at 23% and 22%, and a 6-way tie is more likely than a 2-way tie at 12% vs 9%!  The chances of larger ties diminish pretty quickly, but a 9-way tie is theoretically possible, but it appears a multi-way tie is a very high probability.

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 42% chance it comes down to the sets lost tie-breaker, and there is a 48% chance that is between two teams, a 37% chance it is between three teams, and a 12% chance it is between four teams.  If the controversial tie-breakers are going to come into play, this is the likely spot.

The schedule strengths do vary a lot, the team with the easiest schedule having an opponent average of 4.80 while the team with the toughest schedule having an opponent average of 4.98.  Someone got a bad draw to pull that schedule!  That can clearly lead to an easier road for some teams than others, in fact the strongest team got the easiest schedule.

So who is most likely to come out in the top-4?  Pacific NW, NorCal, Florida, and Mid-Atlantic head the list, PNW the most likely to make it.  Southern, Intermountain, and Texas are all close behind, in fact one of those three is the highest rated team at the event, but also has the toughest schedule.

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.