Friday, February 27, 2015

USTA League match tie-breaks are stressful

My 40 & over team had our first match of the season this evening and three of the five matches went to match tie-breaks.  My match was over, so I got to watch them all and it only reiterated to me how stressful it is to watch, especially since I'm captaining this team this year.

I'm not a big fan of match tie-breaks, but I'd rather be playing one than watching.  Every point means to much that you are on the edge of your seat, and as a captain you stress about thinking if you did your best job getting the line-up right to give your players the best shot of winning.

I understand the reasoning for match tie-breaks, but would still rather play out third sets.  I think fitness and being able to play a full third set should matter and it would help increase the chances the best player(s) win the match and that it isn't decided by a fluke point or two.  But especially where I play, indoor facilities are used the we have limited court times and thankfully we don't do timed matches, so third set tie-breaks give a match a better chance of finishing within the allocated time.

My team was fortunate that we won two of the three tie-breaks and won the team match, so we are off to a good start.  But I'm not looking forward to having to watch more match tie-breaks this year.  So lets win all our matches in straight sets!

Monday, February 23, 2015

2015 USTA League tennis is well under way, estimating dynamic NTRP ratings is too!

If you are a regular reader of this blog, and even if you aren't, you likely know that the USTA "year" for ratings purposes runs roughly from November thru October.  However, "2015" leagues started way back in July 2014 and perhaps earlier where sections/districts have early start leagues.

The way things work, even though these early start leagues are "2015", any applicable matches played on or before 11/9/14 would be included in the 2014 year-end rating and only those matches played after 11/9/14 count towards the 2015 rating.  Similarly, any "2014" leagues that go past 11/9/14 will have those matches count towards the 2015 rating as well.

The result is that matches that are part of 2015 ratings have actually been being played for over three months now and despite it being winter and a particularly harsh one in some parts of the country, due to indoor courts and good enough weather in the southern and western states, a lot of leagues are in full flight.  Many players have played 5-10 matches already, some even more.

That means there are more than enough matches to start calculating Estimated Dynamic NTRP Ratings and generating associated reports.  I've actually been doing 2015 reports since December, even some reports for teams headed to playoffs where their early start or winter league finished up.  I've made a lot of refinements to my year-end calculations to further improve accuracy so I'm fully up and running for 2015.

I can generate a variety of reports including custom reports and lists, the standard offerings being individual, team, and sub-flight reports.  And if you haven't seen the examples or gotten a report in awhile, I've made improvements to all the reports giving you more data and insight.

Individual reports show detailed statistics, match by match analysis and charts, and a partner report showing how a player's matches rate when they play with their different partners.  These give a lot of insight into how each match rated, how your game is doing early in the year and which direction your rating is heading, and who you play the best with.  These reports start at just $20 and once you get a first report updates are just $10 during the regular season.

Team reports show each player's rating and team statistics along with a partner report for the entire team.  These are very useful for captains to know who their strongest players are and who to pair with each other.  They are also a great way to scout opponents to see their trends and tendencies and plan for upcoming matches, particularly in the playoffs where you may not know a lot about the opponents.  These start at $75 during the regular season due to the additional work required and number of players to be analyzed, but you get the ratings and stats for the entire team regardless of roster size and so are a lot more affordable than individual reports for an entire team.

Sub-flight reports show average ratings by team within a sub-flight so you can see who the strongest teams appear to be.  These are a very affordable way to get an idea which matches you need to make sure you have your best line-up available for at just $10 for a sub-flight.


I should note that my reports will always include all matches played to date and always include any relevant playoff matches.  You will never get reports based on stale or incomplete data and you will get the full detail mentioned above including my analysis, comments, and explanations, not just a number.

If you are interested in a report, see the examples at the links above and contact me with any questions or to get started.

Sunday, February 22, 2015

USTA Combo League - Combo doesn't count towards your NTRP rating, but you still want to win!

Many of the USTA sections run Combo Leagues as a secondary league when the standard 18 & over and 40 & over leagues are not being played.  These are doubles only leagues where the combined ratings of the players on the court cannot exceed the level and the level is typically on a half point boundary.

For example, an 8.5 Combo League would have 4.0 and 4.5 players on it typically, although some sections may allow more than a 0.5 ratings gap and so that same 8.5 team could have 3.5s on it and perhaps even a 3.5/5.0 combination getting to the 8.5.  These leagues thus allow friends that aren't at the same level to play together.

To my knowledge, Combo League results don't count towards your rating in any section.  Part of the reason is that there isn't a Combo Nationals like there are for 18+ and 40+ and so no way to benchmark and accurately adjust/level ratings between sections, but also that when you have leagues where players on the court are two and perhaps more levels apart, the USTA has decided the ratings are apparently not as accurate as they like.

All that said, players still want to win, and whether it is just a local league champion, District champ, or Sectional champ, being able to hang the banner at the club is still something players are after.  And despite the ratings not counting, Estimated Dynamic NTRP Rating Team Reports are still a great way to scout opponents.  How can this be if ratings don't count?

While there are some players that play just Combo and so don't have a rating, most players also play in the 18+ and 40+ (and 55+ too) leagues that do count and so they are carrying a rating.  So a team report can still tell you a lot about the strength of a team, who their best players are, and who partners together and what courts they play on.

So if you are playing Combo and headed to playoffs and want to get insight on your opponents, consider a team report.

Thursday, February 19, 2015

How accurate are 2015 Dynamic NTRP ratings at predicting tennis matches? Interesting League Stats

I recently wrote about how well dynamic NTRP ratings do at predicting the winners in USTA League matches by looking at my Estimated Dynamic NTRP Ratings and match results during the 2014 USTA season.  While it is still early in the 2015 season, I thought I'd take a look to see if the percentages have changed.

Here is the same table from 2014 with the 2015 percentages thus far added in.

Winning %
Gap20142015
0.00 - 0.0553%53%
0.05 - 0.1563%62%
0.15 - 0.2575%73%
0.25 - 0.3584%83%
0.35 - 0.4590%89%
0.45 - 0.5593%93%
0.55 - 0.6595%94%
0.65 - 0.7596%96%

We can see that there are no major changes, but 2015 is a hundredth or two lower nearly across the board.  My guess is the reason is that the USTA made some significant adjustments at year-end last year, mostly bump ups, so some players may have ratings that are perhaps a little inflated which has reduced the winning percentages accordingly early in the year while the algorithm attempts to adjust players back to where they should be.

What do you think?  I'll try to update this later in the year.

Tuesday, February 17, 2015

How accurate are Dynamic NTRP ratings at predicting tennis matches? Interesting League Stats


I've been doing sub-flight previews that show how teams stack up by comparing the average Estimated Dynamic NTRP Rating of the players on their roster.  While using average rating doesn't necessarily tell you who will win a sub-flight, for those that I've looked at after matches have been played, for the most part the higher average rating teams are at or near the top.

From this we could reasonably support the notion that higher rated players will generally win more often over lower rated players.  This shouldn't be a big surprise, but it gets more interesting if we dig deeper.

One way to look at how accurate dynamic ratings are is to see how well they predict individual matches.  I did this a little bit looking at some Nationals matches last year, but I've looked at more matches and here is how they do.

Here is what percent of the time the higher rated player/doubles team won a match grouped by the gap between teams looking at matches during the 2014 USTA year.

GapWinning %
0.00 - 0.0553%
0.05 - 0.1563%
0.15 - 0.2575%
0.25 - 0.3584%
0.35 - 0.4590%
0.45 - 0.5593%
0.55 - 0.6595%
0.65 - 0.7596%

No big surprise here.  If players are rated about the same, the match is just about a toss-up.  The bigger the gap, the more likely it is that the higher rated player(s) win.

What may be surprising is how quickly the winning percentage goes up.  With a gap of just 0.2 the higher rated player(s) win 75% of the time.  And by the time the gap gets to 0.4 the winning percentage is 90%.

The above stats are from 2014, but I'll be looking at 2015 soon.  And one can imagine that it is important to get the right match-ups in matches as well and I'll be writing about that.

Stay tuned!

Monday, February 16, 2015

Sub-flight Preview Report - 2015 Southern, South Carolina, Low Country, 18+ 3.5 Women

This is the latest in the series of flight/sub-flight previews I have been doing for 2015.  Today, we take a look at the South Carolina Low Country 18+ 3.5 Women.

This sub-flight has six teams and they stacked up as follows to start the year:

Team NameAverage Rating
L18TH - MPR Perfect Match3.25
L18BG - Creekside Chicas3.23
L18JE - MPR Addicted!3.19
L18KG - Snee Farm Smashers3.17
L18RB - Dunes West String Sisters3.17
L18DO - MPR Slice Girls3.15
L18GM - Hamlin Get A Grip3.14
L18DB - LTP Fireflies3.1
L18LR - Family Circle Thursday Night Lights3.05
L18WR - Family Circle Baby Got Backhand3.05

This sub-flight looks fairly competitive with the top 7 teams all within 0.11 of each other.  Who wins/loses here will really depend on who plays a given match and the match-ups on the court, and who improves the most or plays well on a given day.

So far the big surprises are Creekside is winless and Snee Farm is just 1-2.  Otherwise the top teams are at the top of the standings.

If you are interested in seeing a sub-flight report for the sub-flight your team is in, see this blog post for details on how to leave me a comment here or on Facebook, or if you don't want it to be public, I can generate a sub-flight report for you for just $10.  Contact me if interested.

Sub-flight Preview Report - 2015 Texas Dallas 40+ 3.5 Men

This is the latest in the series of flight/sub-flight previews I have been doing for 2015.  Today, we take a look at the Dallas 40+ 3.5 Men.

This sub-flight has six teams and they stacked up as follows to start the year:

Team NameAverage Rating
Greenhill/Alzuro M3.53.4
McKinney/Jones M3.53.37
Canyon Creek/Gable M3.53.35
Canyon Creek/Nolen M3.53.17
JCC/Mellman M3.53.13
Brookhaven/Love M3.53.02

The top-3 teams were all pretty close going by average rating, but then it fell off a bit.  But this league is about half complete, so how have things played out on the court?  Here are the current standings.

Team NameWLIWILSLGL
Greenhill/Alzuro M3.55020513170
Canyon Creek/Gable M3.54118717206
McKinney/Jones M3.53115511123
JCC/Mellman M3.524131737288
Brookhaven/Love M3.51452041262
Canyon Creek/Nolen M3.50542144279

The top-3 teams are all at the top as expected, although Canyon Creek Gable has a slight lead over McKinney.  So even though using average rating for an entire team does not necessarily indicate who is going to win matches, it appears the three strongest teams are indeed winning their matches more than the lower rated teams.

If you are interested in seeing a sub-flight report for the sub-flight your team is in, see this blog post for details on how to leave me a comment here or on Facebook, or if you don't want it to be public, I can generate a sub-flight report for you for just $10.  Contact me if interested.