Monday, October 14, 2019

Simulating 2019 USTA League Nationals - 18 & Over 4.5 Men

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 third weekend of competition, the 40 & Over 4.5 men'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 341 of the million simulations had six teams undefeated.  The chances of five are quote low as well at less than 1%.

Four undefeated would be a nice and tidy result with no drama, but there is only an 8% chance of that, so we are more than likely to have some tie-break scenarios.

That leaves a good chance, 89%, 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 27%, then five at 23% and three at 22%.  There is a healthy 13% chance of 6-way tie, but just 8% chance of 2-way.  The chances of larger ties diminish pretty quickly, but an 11-way tie is theoretically possible, but it appears a multi-way tie is a very high probability and it could be 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 28% chance it comes down to the sets lost tie-breaker, and there is a 66% chance that is between two teams and a 28% 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, the team with the easiest schedule having an opponent average of 4.44 while the team with the toughest schedule having an opponent average of 4.57.  This leads to an easier road for some teams than others, in fact one of the strongest teams got the easiest schedule.

Note that as the size of the potential ties tells us, this is a very competitive group of teams at the top with the top-5 teams separated by just 0.05 on average rating.

So who is most likely to come out in the top-4? Mid-Atlantic, TexasIntermountain, and NorCal head the list, Mid-Atlantic the most likely to make it.  Middle States and Florida are nipping at their heels, Eastern, Southern, and SoCal needing an upset or two..

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.

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