Letters from Users (and some articles)

December 6, 2022

Hi David,

Just wanted to say I’ve recently noticed the updated match search and rating history graph functions and REALLY love them. It’s great to be able to see the data in all these different ways.

Thanks for all of your hard work on the system!

Zachary Anstey
Coburg TTC, Australia

October 26, 2022

Hi David,

Finally, thank you for creating and maintaining such a valuable resource.

David McGrath

March 1, 2022

Hello David,

Thank you for creating an accessible program for the table tennis community,

Cameron Eggart

May 11, 2021

Hello David,

I have really enjoyed using the software while running tournaments for the University of Idaho’s table tennis class. Five total events have been logged and about 35 new players added to the Ratings Central system (a lot of who will continue playing at the school’s league and regional tournaments).

Thank you for your time and creation of this software,
Cameron Eggart

March 3, 2021

Hello David,

After reading through the manual, I have successfully uploaded my first event to Ratings Central (Event ID: 39473). First off, impressive software and manual. I’m sure I can’t imagine the amount of effort and time put in. The tutorial was helpful and the manual easy to work with.

Thank you for your time and insights,
Cameron Eggart

January 6, 2021

Dear David,

Thanks for your superb rating system that is really helpful to us.

Suhaidin Azhar

September 3, 2020

I really enjoy using the Zermelo program to run tournaments due to its efficiency and simplicity. I recall the days of the manual processes and many hours required to seed players, do draws, and then run a tournament, all of which are now substantially reduced due to Ratings Central and Zermelo.

Anyway, keep up the great work with Ratings Central and Zermelo.

Andrew Freer
Treasurer, Moreton Bay Table Tennis Association

June 19, 2020

And thank you for a great service. I used to do our own ratings years ago but your system is certainly better and more convenient (except for trying to explain standard deviation ;-)).

Bruce Kline
Champlain Valley Table Tennis Club

August 3, 2019

Mr. Marcus,

Thank you for developing and maintaining your rating system. This has enabled our club (Omaha Metro Table Tennis Club — OMTTC in Nebraska) to efficiently run non-sanctioned tournaments. We will be making a contribution to Ratings Central at our next tournament.

Thank you for your help,

Rod Cowles
Director, OMTTC

May 14, 2019

Hi David and Sean,

As event director, I like Ratings Central very much … I think it is an ingenious and smoothly working website and I look forward to continue using it to tabulate our results.

Kevin Alexander
Fort Collins Table Tennis Club

March 24, 2019


First of all, I take this opportunity to thank you for such amazing website. It provides an excellent record of a player’s performance, history and trend. It is a wonderful resource.

Shaun Ang

March 20, 2019

Hi there,

Well done on the Ratings Central site—it’s an amazing resource!

Many thanks,
Robert Stillwell

November 26, 2017

Hi David,

Please accept our small contribution of $20 AUD in recognition of the tremendous service you provide to table tennis players. The money has been forwarded via PayPal.

Yours sincerely,
Richard Mielczarek
The Sunbury & District Table Tennis Association, Victoria, Australia

November 22, 2017

Hi Support,

I‘m the match recorder for WTTA in Melbourne, Australia and recently we ran a Veterans Tournament using the Zermelo program. This is a great program and was more impressed to see a direct upload to Ratings Central. … Programming interfaces is not new to me as I have been in the SCADA industry for over 25 years and have written some complex programs. …

David Bartolo

October 17, 2016

Dear David,

My name is Fabio Zambetta, a player in the Sunbury & District TT Association (where Robert Katsipis is also based) and a lecturer in Computer Science. Rob may have mentioned to you I am writing a Windows app to manage our pennant, which interfaces to Ratings Central.

Fabio Zambetta
Senior Lecturer
School of Science, RMIT University

P.S. Many thanks for Ratings Central, it is a great system and I thoroughly appreciate the model behind it (my area of expertise is AI in computer games, so I do know what your equations are for) :)

October 11, 2016

Hi David,

I see. I will read the user’s guide much more thoroughly now, and also try things out on the Windows machine tonight. Thanks again for the help, and, most importantly, for designing and maintaining such a phenomenal rating system!

Cory Trainer
Paddle Palace club

May 3, 2016

I played at the NSW [New South Wales] Country Championships on the weekend. About 200 people competing. Great fun was had by all (along with a few whinges from people who don’t like my long pips!). Interestingly, there was quite a lot of discussion about Ratings Central and how it all works. A number of people were asking others how it works etc.—it was good to hear a number of people singing it’s praises (me among them!). Might not be too long before NSW TT Federation joins the long list of “official” users.

I do like the way that the Bayesian probability system works—it seems to me that it provides a pretty good indication of a person’s standard. Someone who is improving quickly can be a bit of a surprise package in ratings terms for a while though!

Thanks for all your efforts with this. It is a great contribution to our sport.

Dr. John

Date: January 17, 2016
To: David Marcus, Greg Bristowe, Gerard McCarthy, Jeff Dever
Subject: Insports Table tennis sub-portals go live with Ratings Central interface

Greetings All,

I would like to pass on my sincere thanks to you for the time, effort and assistance provided in making the integration of the Insports table tennis sub-portals with Ratings Central possible.

Special thanks goes to Greg Bristowe (Croydon and Districts Table Tennis Association) who burned the midnight oil testing and helping iron out the bugs of the interface. The system went live in the wee hours of Saturday morning (16/01/2016 AUS time).

Thanks David for helping us sort out the pitfalls of the USA vs AUS date conversion; and thanks Gerard for working with us to develop a download to RCPennantSubmitter and the changes you had promptly incorporated into your software.

This joint collaboration will greatly assist clubs with their pennant processing and centralized ratings.

Andrew Kurdzinski
Internet Sports Services (ISS)

January 15, 2016

Hi David,

I have uploaded all our singles matches with no problems. Our members do like your system and appreciate your effort and time and making this rating system available for us to keep track of our matches and ratings. Thank you!!!

Thanks again,
Den Lin

October 9, 2015

Hi David

We are using your system. It is very good system, easy to use, clear presentation. We appreciate what you’ve done.

Thank you for your time.

Kind regards
Allan Xu
Sydney Northern District Table Tennis Association

October 7, 2015

After just reading about you and Ratings Central, I am glad TTV (Table Tennis Victoria) and my local club have started using your system. I admire your hard to work to achieve your Ph.D., your work history and contribution in the table tennis industry. The world is a much better place having such hard working motivated people like you around that will give your time, knowledge and experience to others … and also take the time for the minutiae such as updating a database with an email address!

Many thanks David.

John Griffiths
Melbourne, Victoria, Australia

August 3, 2015

Hi David

As an engineer and currently a student of ICT (information and communications technology) I am always thinking of ways to improve the ergonomics of running a tournament. So your systems are very inspiring.

Glenn Errington
South Australia referee

July 19, 2015

Hi David,

I am still very happy with your system to process our hardbat tournaments.

More and more people in the Netherlands now think it is a good system as an indication of the player’s strength in hardbat.

Kind regards,
Matthieu Wegh

May 7, 2015

Hi David,

Jessie T. Zhang

P.S. Just wanted to say that I think Zermelo is a great system!

May 7, 2015

Thanks David. … Everything you have done with this project makes managing tournaments so much easier, and more fun.

Michael V. Lauro, Jr.

April 7, 2015


Holy crap you rock. Absolutely perfect. Thanks for the assistance and all that you do!

Dan Emord
Genesee Valley Table Tennis Club

April 3, 2015

Hi David

Thanks again for this great service. Your API documentation was excellent. The personal help sorting out the Pascal interpretation for encryption then encoding was essential. Having made many little silly mistakes in trying to create more than 12 months of Event Reports in just a few hours, I have been very impressed with the error checking and automated emails that your system provides. The resubmission process is so simple.

Happy Easter on Sunday

All the best,
Gerard McCarthy
ES&CTTA Admin Secretary and Website Manager

March 29, 2015

… So glad you created Ratings Central, even if I don’t use it yet. Thanks for creating Zermelo; it rocks.

David C. Evans III

March 23, 2015

Hi David,

Hope all is well with you. …

This past weekend there was a table tennis tournament at … . I went to check it out and watch top players playing. The tournament managers were using … software to run the tournament. In my opinion, the … software sucks. Zermelo is a much better system in many many ways. The scheduling, arranging matches, printing of match cards and the flexibility in managing the tournament are much better using Zermelo. Thank you for all the work you have done to make the Zermelo software available for the table tennis sport.

Mohamad Al-Sabek

March 20, 2015

Used Zermelo to run last week’s 4-Star Butterfly San Francisco Open—235 Players and 40 tables! Largest tournament I’ve been asked to run! The tournament director and Butterfly haven’t decided yet if they want to post results to Ratings Central—so I decided to pay you first. …

Yau-Man Chan

March 10, 2015

Thanks David,

BTW, if I haven’t already told you—both Zermelo, Cantor, and the Ratings Central experience is awesome, you don’t have to convince me.

I was just trying to be really good at using it, as I have to train up all our clubs, and I can forsee the questions they may ask.

On another note—do you ever sleep?

Thank you again for all your help.

Kind Regards
Robert Katsipis
Technical Committee Chair, Table Tennis Victoria

February 25, 2015

Dear David,

I have been using Zermelo for over 12 years now. It is a great program and I would not run a tournament without it.

Alan Grambo

February 2, 2015

Dear David,

Thank you very much for the help!

I used your software to run the tournament and like your software very much. It is very helpful. I re-checked my results and only found a few entry errors but all these errors are numbers not games. This is amazing considering we had about 280 games in one day.

Again, I really like and enjoyed your software and rating system. Thank you very much for making such great software and making it publicly available. …

Best wishes,
Kui Zhang
Vestavia Hills, Alabama

January 10, 2015

FYI: Thanks for Zermelo and Ratings Central. Everytime I use Zeremlo to run a tournament, I learn something new. Today I learned how to conduct a 2-stage round robin format with the first stage being one event (5 groups of 3), followed by a second stage to which all players advanced. The second stage consisted of 3 groups of 5, depending on the place that each player finished in the first group. The second stage groups were separate “events”. During setup of the events, I predicted where each player would finish based on seedings, and added them to the appropriate second-stage event. After the first stage was done, I only had to juggle a few players among the second stage events, and it worked like a charm.

Michael V. Lauro, Jr.

September 1, 2014


The processing of the results is very quick and amazing. …

Thanks again for providing a great program which uses the power of statistics and probability functions to accurately assess a player’s skill rating. For our club we have been able to set up a meaningful competition and not have to artificially put players into grades. Players are grateful that they can see their results quickly and all the scores against their opponents. This allows them to plan tactics for future matches or see what problems they have against various styles of players.

Tombo Lee
Cherrybrook Table Tennis Club

August 29, 2014


Thanks for your help. And a word of appreciation that our club members enjoy the competition that is possible due to the quick and accurate rating system that rewards players winning against higher-rated players.

Tombo Lee
Cherrybrook Table Tennis Club

August 25, 2014

Hi David,

Thank you for allowing us to use this magnificent program Zermelo. It made running our tournament a breeze.

Kind Regards,
Robert Katsipis
Technical Committee Chair, Table Tennis Victoria

August 7, 2014

Hi David,

We are very happy with the program [Zermelo]—last week was the first time we have used it to call matches and it went really well. You have done a great job.

Thanks and regards,
Jeff Grubb
Bendigo & District Table Tennis Association, Victoria, Australia

July 28, 2014

Hi David,

Thank you for your great application [Zermelo] and all the work you put into it.

Jared Stanley
Mackay Table Tennis Association

April 12, 2014

… I have input two events into Ratings Central, and the ranking of Scottish players that have played since 2010 now looks like …

Was impressed at the painless nature of uploading via Cantor. I am quite happy with the numbers, a few outliers but a problem with lack of results rather than priors I think.

Gordon Muir
Edinburgh and Lothians Table Tennis League

January 25, 2014


Enclosed is your check for our just-completed 2014 Winter Sooner State Games.

I had a grand total of zero significant problems! The only minor problem was quickly resolved by the user’s manual. (I couldn’t figure out how to do a double default.)

Also, I had a volunteer help with data entry, and she seemed to pick up on the software [Zermelo] quite well. This gave me more time to devote to “bigger picture” stuff.

Britt Salter
Oklahoma City Table Tennis Club

January 16, 2014

Hello Marcus

Our players are very happy with your service. We have been doing this for 1 year now.

Neil Cossey
Port Macquarie Table Tennis Club, Australia

September 1, 2013


I really appreciate your excellent Ratings Central site and software. It’s a huge contribution to the sport of Table Tennis and I am grateful for your efforts.

Tom Kisler
Des Moines Table Tennis Club

June 29, 2013

Hello David

Our Club has been using Ratings Central successfully for 16 weeks and our members are really pleased with it. Thank you for the program.

Neil Cossey
Port Macquarie Table Tennis Club, Australia

May 11, 2013

Hi David,

A quick note to say thanks for the use of your Zermelo software. We used it recently at our RITTA Spring Open.

We got many compliments on running a very efficient tournament, and much of it was due to Zermelo. As a database developer, I can appreciate the work that goes into making a good quality piece of software. We look forward to using it again at our next tournament in September.

Manny Silva
RITTA President

A Self-Defeating Adventure in Self-Rating” by Paul Wachter, The New York Times, December 22, 2012.

This article is on the U.S. Tennis Association’s league ratings.

June 30, 2012

We really appreciate your Cantor program and Ratings Central.

Thank you,
Rod Cowles
Omaha Metro Table Tennis Club

June 29, 2012

Sehr geehrter Herr Marcus,
lieber David!

Möchte mich im Namen des Kärntner Tischtennisverbandes und vor allem der vielen Jugendlichen, für die Tischtennis eine sinnvolle Freizeitbeschäftigung ist und so diese von vielen negativen Dingen ablenkt, sehr, sehr herzlich für die Entwicklung der Rangliste bedanken.

In Kärnten sind alle Funktionäre nur ehrenamtlich tätig, es gibt auch kein Büro und so war es uns eine sehr große Hilfe, deine Rangliste übernehmen zu können. Unser Ranglistenreferent Kurt Goritschnig, der auch mit Hrn. Baurecht gut zusammenarbeitet, ist in Sachen EDV gottseidank auch sehr bewandert und so können wir nunmehr unseren Tischtennisspielern ein wirklich gutes Service bieten.

Nochmals vielen, vielen herzlichen Dank und alles Gute für die Zukunft.

Liebe Grüße
Karl Waldhauser
(Präs. KTTV)


Dear David!

On behalf of the Carinthian Table Tennis Association, and especially in the name of the many young people for whom table tennis is a meaningful leisure activity that distracts them from so many negative things, I want to thank you very very much for the development of the rating/ranking system.

In Carinthia, all officials are just volunteers; there is no office. And so it was a great help for us to be able to use your rankings. Our ranking officer, Kurt Goritschnig, who works well together with Dr. Baurecht, has thank God much knowledge in IT, and therefore we now can offer our table tennis players a really good service.

Again, many, many thanks and best wishes for the future.

Karl Waldhauser
(President KTTV)

Ratings Central: Accurate, Automated, Bayesian Table Tennis Ratings for Clubs, Leagues, Tournaments, and Organizations” by David J. Marcus, NESSIS (New England Symposium on Statistics in Sports), September 24, 2011. Video of David‘s Presentation, Program and Abstracts, Presentations and Videos, Photos.

Ratings Central: Accurate, Automated, Bayesian Table Tennis Ratings for Clubs, Leagues, Tournaments, and Organizations” by David J. Marcus, Joint Statistical Meetings, July 30–August 4, 2011. Session, Abstract.

June 21, 2011

Thank you for the great rating Web application that we are using right now.

Resty Rojalez

Das Ranglistensystem von Ratings Central”, part 2, by Dieter Baurecht, ÖTTZ (Österreichische Tischtennis Zeitung), No. 100, May/June 2011, pages 8–9.

March 22, 2011

Hi David,

This system is very easy to use.

I know most of our players and the ratings are looking good at the moment. By the time I have entered 2010 results it should reflect abilities.

Doug McLean

March 15, 2011

Hi David,

First of all I want to thank you for Zermelo and Ratings Central. It works great!

Adrián Boimvaser

Das Ranglistensystem von Ratings Central”, part 1, by Dieter Baurecht, ÖTTZ (Österreichische Tischtennis Zeitung), No. 99, March/April 2011, pages 8–9.

February 24, 2011


Thanks for the work you are doing on the ratings. The players do appreciate it.

My club is located in a sports bar with six tables and it is growing to the point that we are pretty much to the limit on the number of players we can handle. In a large way Ratings Central has helped the growth. We have a team league over four days with 96 players and will most likely go to 5 days with 120 players. I think beer and Ratings Central is the answer to all the problems.


January 19, 2011

Dear David,

Using the strong support of our friend Dieter Baurecht, the Austrian Table Tennis Association is from now on using Ratings Central as its official ranking system.

We have tried and used quite a number of different ranking software systems, but were not able to find one which could be adapted to our requirements.

However, our experts are convinced that with Ratings Central we have now found an excellent tool for arranging an accurate and fair ranking of players participating in Austrian table tennis.

So let me please express my sincere thanks for providing this system to us.

I hope you are planning to visit Austria in the near future. We would be happy to have you as our special guest at one of the forthcoming international table tennis events in our country.

Looking forward to keeping in touch with you,

Rudi Sporrer
General Secretary
Austrian Table Tennis Association

December 12, 2010


Thank you very much for giving such amazing software [Zermelo] to TT community. ICC is using your software for the tournaments.

Rajul Sheth
India Community Center Table Tennis

December 5, 2010


The software [Zermelo] worked out great. We could not have done the tourney without it.

Thank you for your efforts.

Jeff Webster
Colorado Springs, CO

November 2, 2010

Hi, Sean and David.

As I’ve now submitted all of our tournaments to date I thought it a good time to review the results. I have to say I am very impressed as the ratings are pretty much in line with what I was expecting at the start.

David, may I also compliment you on the software [Cantor]—once I got used to it, it was very easy to use, even for a Luddite like me! Now that I have used it and seen the accuracy of the ratings, I would be very pleased to recommend it to anyone.

Thank you both very much.

Chris Pickard
Hardbat English Association Of Table Tennis

September 4, 2010

Thanks! I’m still getting used to navigating through Ratings Central.

This is the best ratings system I have seen for table tennis and perhaps for any sport. I wish USATT would consider it. The USATT rating system is inflated and not as accurate as it should be.

Keith Pech

July 21, 2010


Again thanks for your work. The players here in Portland really enjoy the rating system.

Tim Titrud

June 17, 2010

NÖTTV Interview with David Marcus

November 21, 2009

Hi, David.

Thanks for developing and hosting Ratings Central. It has been very useful in our local leagues in helping us know players’ current skill level.

Thanks again for providing the rating service. It’s really allowed us to create better league teams, seedings within our club, etc!

Brian Clark
Table Tennis Minneosota

October 24, 2009

Hi, David.

The club here at UC Berkeley has recently been using Ratings Central to facilitate our weekly round robins and it’s working out very well!

Mark Wei
President of Cal Table Tennis Club

September 13, 2009

Tomorrow the Maine Table Tennis League will start our new season of table tennis. We have 8 permanently set up tables and 70–80 members now.

The Ratings Central website has been invaluable in helping us rate the players.

Rick Shea

August 29, 2009


Cantor is such a great program and is so easy to use. Our players really enjoy seeing the results.

Thanks for all your work with Ratings Central.

Ray Spann
Lakeland Table Tennis Association

August 29, 2009


… I like the fact it is free, easy to use, and allows for immediate posted results.

I also feel that overall, it is superior (more accurate) than the USATT rating system.

Russ Walker

August 9, 2009

Hi, David.

By the way, thank you so much for the assistance and the great online rating is so far the best and also for the great software Cantor :) very friendly and with the complete manual.

Ratings Central is very effective and useful. This could eliminate players who give matches to their friends. This means that every match has a bearing …

I love this! Thanks David.

Resty Rojales

August 7, 2009

Hello again David.

I spent a lot of time to study the software and Cantor Users’s Manual.

First of all I would like to thank you for creating this program and for sharing it with all table tennis fans around the world.

I think it is a great and easy to use software.

Best Regards,

Atanas Gadje
Table Tennis Fans

July 22, 2009


Thanks for your prompt attention to my problem. The players here really enjoy watching their rating results; it adds significantly to their enjoyment of the game. We wouldn’t like to be without Ratings Central, since it is invaluable setting up the draws and giving feedback to the players.

Thanks again,
Joseph Sabas

December 4, 2008


Lower Austria is one of nine Austrian provinces and the home of Werner Schlager. The Lower Austrian Table Tennis Association (NÖTTV) has introduced the Ratings Central system as the official rating and ranking system starting with the 2008–2009 season. Since the data was available, we first submitted a lot of events from previous seasons, enabling us to start with a large number of already-rated players. We use the system for all purposes where a ranking list is necessary, and players love to inspect their results weekly. We also extract ranking lists of individual groups out of the system, e.g., different age groups (young players as well as veterans) or women.

Games of all our events are submitted weekly including all playing strengths, genders, and age groups: from Austrian First League to the under-eleven junior leagues, all tournaments, and a Cup system. Due to your submitting results of events from the ITTF Pro Tour and European Champions League, our best players are also rated in the same system—something we never had before. Although most of the leagues are played in isolated local regions, Lower-Austrian-wide events calibrate the playing strengths of the different regions quite well so that we have for the first time an accepted ranking system for the whole of Lower Austria.

Of course, in the beginning it took some time to persuade players of all the advantages of the system. Now, most of them (especially the interested ones) have learned how point changes occur and what the size of point changes depend on. Although the algorithm that produces this is not understandable in detail for most of us, we see that the system works very well. So, I can attest that it is much better to have a well-accepted ranking system using a sophisticated algorithm than to have a system where point changes are done by a few easily understood rules that result in an always-disputed rating list. For the first time that I can remember, there was no discussion about the draw at the 2008 NÖTTV championships! ;-)

In addition to the quite perfect ranking, the history graphs are a great feature to track playing strengths. In particular, we can monitor the development of young players not only on the table, but also as hard facts.

Therefore, when talking to our players, we get a lot of very-positive feedback that really should be passed to you and your team. Thanks a lot for your work.

Dr. Dieter Baurecht
Board Member
Lower Austrian Table Tennis Association

Photo of Dieter, Werner Schlager, players from Dieter’s club
European Champions League match
December 11, 2009

December 4, 2008

Thanks so much for your help, David.

I’ve managed to post (incorrectly because I inputted estimated ratings for new players) and re-post one of the divisions of the tournament. So easy—and it looks great! Thanks so much for this.

I will work on inputting the rest of the events, slowly but surely. We ran a 3-person team event, so I’m trying to use a format that will allow me to post only the matches that were played—and delete the matches not played. We’ll see how that goes.

Love the software. We tend to run some funky formats here (2-person team RR, etc.), so it may take a bit of tweaking.

Much appreciated!

Craig Tafel

April 15, 2008

Hi, David.

Thank you for your quick response, and for granting me access to the data files (which I have since downloaded).

David, I have already begun experimenting with your software (and data), with a view to using it to ensure the smooth running of the 2008 WTTA “Wynnum Open” on the 26th and 27th of this month.

It is only early days at this time, but from what I have seen thus far, the software looks to be very functional and a well thought out system (including your “user friendly” documentation). I too am a computer programmer (20 years experience), and can fully appreciate the tremendous amount of time you have so willing put into your application. The “Table Tennis Community” is just so fortunate to have great people like yourself, who have such a passion for the sport, that they are prepared to dedicate their personal time (purely out of goodwill) to assist others—Truly commendable—Well done!!

Thanks again David for all your great work in this regard, and I will be in touch again in the near future—Thank you.

Grant Beale

October 17, 2007


Your reply triggered a thought for me. We have been having a series of Foothills Celebrity TT (2-star) tournaments at our scruffy little city here in Knoxville, TN. While we play in a YWCA gym that barely permits us to process 52 players, we have been fortunate to attract celebrities like Danny Seemiller, and we make up some of our facility shortcomings with a lot of care and friendship from our club members, so we have been getting very nice feedback from participants in our tournaments that mostly come from this region, although we’ve had a few from New York and Florida. We typically have a coaching clinic (led by our celebrity) on a Friday and play our matches the next day from 9 a.m. to about 6 or 7 p.m.

I know we are very happy with the use of Zermelo and from that standpoint you are a celebrity for us. I have no idea how many people are using Zermelo or if you have ever had some kind of regional or national gathering, or how you promote your program other than making its presence known over the Internet. One of the nice features of Zermelo is that is basically user friendly, but I know we would have several of our own club members participate in a seminar type session if you led it.

Just a thought, but would appreciate you letting me know if the idea interests you. If it does perhaps we could make it happen.

Take Care,
Dwain Kitchel
Knoxville Table Tennis Club

A Story of the Rating” by Jota Ito, World Table Tennis, December 2007, volume 127, page 147.

Click the link above to see the original Japanese. The following translation is by Shigeaki Nishina.

A Story of the Rating
by Jota Ito

What is the best way to introduce a rating system, numerical evaluation of players’ strengths, in the Japanese table tennis world? First, we need to determine the target players. High school or junior high school students are the most active table tennis players in Japan, so you might think they would be the best targets. But unfortunately, they are not. Because a rating system detects absolute strength of players based on relative strength, or match results, it does not work well for a group whose members are all getting better and better every match. So, although it might sound ironic, the system should be introduced mainly for college students or older players, whose table tennis strength is stable. Secondly, we have to find out someone who can actually introduce and run the system. The simple and reasonable answer is JTTA. But highly possibly it won’t happen. There is no one who are actually feeling inconvenience without a rating system in Japan. “Looking interesting” will not be a sufficient reason for them to bear monetary and labor costs.

So, what is the possible story? Use the Internet. What if someone, who has spare time and computer skills, makes a rating system, collects the match results from all over Japan, and calculates the ratings for players, independently? Of course, such a system does not have any authority or practical effect. It would be just for table tennis fans enjoying discussion about the matches. But it sounds fun, doesn’t it? And if the calculated ratings accurately evaluate the players’ strength, it could become popular. And finally, it could have some authority, or could become even a standard. At this point, JTTA might want to adopt the system. Then just let’s give it to them.

After dreaming of such a story for a while, I sent an email to USATT and asked about the theory on which their rating system is based, and the outcome was quite unforeseeable. I received a reply from a man named David Marcus. “There’s no theory in the current USATT rating system”, his email said from the beginning. It continued saying that the USATT’s method is determined arbitrarily based on their experiences, and not based on any theory. I felt from his arrogance that he is not an ordinary man, and knew that he has a doctor’s degree in probability from MIT, the world-famous university known as a Nobel Prize factory. According to him, there’s another table tennis rating system developed by himself. The system is designed to hold each player’s table tennis strength as a probability distribution, and update the distribution based on a “probability-of-upset function” and match results, in a way with logicality and strictness that all the people who major in science and engineering would love. Why isn’t the system adopted by USATT if it is superior? He explained the reason to me, “The USATT president Sheri and her followers hate me.” You would see the personality of this person by the fact that he told such kind of a story in the first emails to someone he has never met. Well, I like such a person.

Then he showed me the Ratings Central website, and it made me jump up in surprise. Believe it or not, the site collects the match results from arbitrary tournaments including the World Championships and Pro Tour, calculates the players’ ratings using his system, and opens them freely to the public (of course, no players nor ITTF would know this). According to the site, Wang Hao holds the highest rating,3175​±38 (mean ± standard deviation), and Jun Mizutani has the highest among Japanese, 2956​±36 (as of October 4, 2007). Furthermore, the site allows everyone to register players and enter match results. What I dreamed already exists here. Amazing!

So, if you are the person who is interested in the idea I wrote in the first part, please access this website and enter results of tournaments (you will need some communication with him in English). Because there have already been around two hundred Japanese players registered in the system, it would be good to start from JTTL or All Japan Championship, the tournaments in which those players play, and then move on to the other tournaments for general players, so as to expand it to nationwide with keeping the accuracy of the ratings. So far, the total number of registered players is about seventeen thousand primarily from the US, and he said no worry about the storage limit. The system doesn’t have a fancy display for distribution for example, but it is still the first and only rating system that covers tournaments worldwide. We can become a friend even with people from countries we have never heard through the rating system! This is all possible only at this IT age. How magnificent and fun it is!

September 15, 2007


Thanks a lot. I am sure you heard this before, but your software [Zermelo] is exceptional. There is a bit of a learning curve, but it’s very powerful.

Thanks again,
Ivan Popov
Michigan Table Tennis Academy

March 9, 2007


I have been using Zermelo every week and I like it very much …

Joseph Sabas

December 11, 2006


Zermelo was great, and I got only good compliments from the tourney I just ran, and a lot of that credit has to go to the software you developed. …

Shashin Shodhan

September 27, 2006

Dear Mr. Marcus,

Our company has just completed our table tennis tournament, and it was a great success. Your Zermelo software has made the organization of the tournament much simpler than it would have been. Thank you for a great piece of software.

Gideon Fung

May 30, 2006


Just to give you an update. I ran the Golden State Open 2006 with Zermelo version 15.4 this weekend. 2 days, 23 events, 24 tables, and 278 players—amazing—the biggest event we’ve ever done. Everything ran well. Just to let you know some of the highlights:

  1. The notes for players was wonderful—the cashiers loved it—they know why the player owes money or gets a refund when asked without having to dig through the original entry forms.
  2. Check-in was a breeze—we had a lot of compliments on how smooth and simple the check-in was. Using the export feature, I mail merged their name on the USATT waiver and their ID number on the top corner, in a tiny font. All they had to do was sign the form. The check-in person then checked the ID number on Zermelo to check them in—a two for one process—if they signed the form and turned it in, they are checked in.
  3. Also using the export, I was able to do a mass mailing to players to confirm their entry—cut down on a lot of phone calls from them asking if we got their form!! Also, the export helped in making our program where we list all the players and the city and ratings.

The only problem with calling matches in a big tournament like this is people not returning their playing slips. When I noticed a match slip out for over 45 minutes, I went looking for the players and found one of them sitting around chitchatting with her friends—match slip in hand. I don’t know what to do about this other than to send out a spotter to keep harassing players to turn in their match slips as soon as they finish. The gym is three basketball courts in size and the control desk is in the lobby—can’t see the players. So, maybe a reminder in Zermelo to prompt the control desk that a match slip has been out for over thirty minutes?

Again, thank you for a wonderful program. The Golden State Tournament committee is now totally sold on match calling and will continue to use it in the future.

Yau-Man Chan

April 27, 2006


Our club used your program [Zermelo] for our recent tournament [Dogwood Arts Festival First Annual Table Tennis Open]. It worked like a charm and our tournament ran smoothly—almost like we knew what we were doing. If you are the guy who developed this program and supporting manual, all I can say is a helluva great job! Thanks!!

Dwain Kitchel
Knoxville Table Tennis Club

October 6, 2005

Btw, your new added feature for version 15 is exactly what I was going to suggest. Our tournament committee for the Golden State Open has decided to continue to use Zermelo in next year’s tournament because of that additional feature. They want to do timed events for the RR groups and match calling for the SE rounds.

Thanks again for a wonderful program.

Yau-Man Chan

September 27, 2005

[Zermelo is] an exceptional program and I encourage all directors to use it.

Greg Thompson

June 16, 2005

There are three men from Taiwan on the Class 5 (wheelchair) IPTTC (International Paralympic Table Tennis Committee) Ratings Central rating/ranking list. Before the National Championships on May 29, 2005, they were ranked right next to each other in places 9–11:

91886​±58Ching Chin Tsai
101880​±73Yen Hung Lin
111877​±76Chih Jung Chang

Many players and coaches in Taiwan did not believe these ratings/rankings. They thought there must be some error because, in the past, Tsai almost always lost when he played Lin or Chang. Lin and Chang competed in the 2004 Paralympic Games in Athens and are not beatable in Taiwan.

Tsai is a nobody and can only participate in open tournaments by paying his own way because he doesn’t have enough ranking points on the official IPTTC ranking list to qualify to be selected for major international events, such as the Paralympic Games. (While IPTTC is currently testing/evaluating Ratings Central, the official ranking list uses a system where players accumulate points based on international match wins. The more tournaments you play, the more points are available for you to accumulate.) Tsai has beaten some very good players recently in international tournaments, but hasn’t played as many such tournaments as others in his class.

However, in the National Championships, Mr. Tsai beat both Mr. Lin and Mr. Chang and became the Men’s Class 5 Champion! As a result, Mr. Tsai is now on the National Team and will participate in the Tribute to Peace World Wheelchair and Amputee Games.

The Ratings Central rating system has done a very good job of predicting true playing strength. Mr. Tsai’s results are only one of many examples of this.

Dr. Chi-Shih Wu
Former Director for Rankings
International Paralympic Table Tennis Committee

June 13, 2005


As I mentioned previously, this is the first time I’ve used Zermelo to run such a big tournament—2 days, 240 players, 21 singles and 3 doubles events—a total of 713 event entries. I was able to use Zermelo to streamline the check-in, especially with the new USATT rule of having each and every individual player sign a separate waiver. What I did was mail merge the names onto each waiver. On the top-right corner, I mail merged the player ID, and on the lower-right corner, I mail merged a “see cashier” on players who owed money.

The check-in worker just had to give the player their pre-printed form. The player would then find a flat surface to sign it and put it in an in basket. If they didn’t return it, they were not checked in—the data processing person periodically picked up the forms and checked the player into Zermelo using the ID printed on the form. Voilà! No check-in line. Only players who owed money had to stand in line—only 23 out of 240 entries—their penalty for not doing the math correctly and paying the correct amount when they sent in the forms!!

All in all, the program worked great.

Yau-Man Chan

April 18, 2005


Used Zermelo for the first time on Saturday. I liked it a lot. We had 70 entries in 11 events on 12 tables. Began at 9:15 a.m. and finished at 5:40 p.m. with all events in four-man round robins!

Ed Hogshead

January 26, 2005


… I once again wanted to thank you for making such a great resource available to the table tennis community.

It is through the efforts of people like you and Scott Gordon that keeps table tennis a community instead of just a bunch of players.

Howard Blum

January 24, 2005


I continue to be amazed at the quality of Cantor. Since I input results into both the USATT League system and Cantor, I much prefer using Cantor.

Raymond D. Spann
Lakeland Table Tennis Association

December 23, 2004


I just want to thank you for your assistance and patience while helping me import the 116 historical AGTTA [Atlanta Georgia Table Tennis Association] league sessions into Ratings Central. Without it, AGTTA would not have this excellent resource for our members.

René Nielsen

December 22, 2004


Thanks for all the work you have done on Ratings Central. It is now a great deal easier to use. I am going to try to get the other clubs in Oregon to use it.

Tim Titrud

October 20, 2004


My club has been using Ratings Central for two years now, and we find it useful and exciting. It really is a neat program/service if you like to play for rating points and consider them a sign of progress (or lack of). And, it’s absolutely free to us!! The results are processed within minutes once we have entered them, so we get almost immediate feedback of results. And, the Ratings Central rating system eliminates wild swings in ratings—up or down.

For me, it has been similar to playing in a tournament twice a week for two years! Some people may not like the pressure it can put on you, but I am sure that if a club tries it out, they will arrive at a suitable conclusion of if, and how often, to count matches for ratings. For me, it nearly fulfilled my need for the pressure, and made it more likely that I would pass on USATT tournaments since I got, in effect, the same intensity of play and pressure without having to travel.

Rick Mundy
Tidewater Table Tennis Club

October 11, 2004


Zermelo worked flawlessly.

Please add the following new features:

Larry Rose

October 6, 2004


Thank you for Ratings Central’s support of the Rhode Island table tennis tournament on Sunday, September 26.

This was our first non-USATT-sanctioned tournament. The tournament was very successful: we had 60 participants, including the two highest rated players in Rhode Island and Connecticut, and 24 unrated players who had never played in a tournament before. In comparison, our August USATT-sanctioned tournament (which we also submitted to Ratings Central) had only 44 participants.

Everyone was impressed with the speed and accuracy of Ratings Central’s posting of the match results. Not only were the results posted very quickly (the evening of the tournament day), but Ratings Central sent each participant an email containing a link to the player’s own match results.

We especially appreciated the fact that there are no membership dues nor any fees associated with Ratings Central. Since the cost was very low, players were able to play more events.

We look forward to running many future Rhode Island table tennis tournaments with Ratings Central’s support.

Thank you!

Chuck Cavicchio
Rhode Island Table Tennis Association

August 17, 2004

Hi, David.

Using your software was very easy, the tournament seemed very organized, and you were very helpful in every question we had.

Mohamad Al-Sabek

May 3, 2004


Thank you for Cantor!

Submitted my first matches for a tournament in April for the Virginia Tech T.T. Club. My biggest surprise was how fast the ratings had been processed, immediately!

And as for the program, my work as Ratings Director for the NCTTA has just become so much easier.

I think I can convince now most of the college clubs in the US to use the system also.

Seemant Teotia

May 2, 2004

Hi, David!

Zermelo was flawless Saturday, that is, once I figured out that our U1400 RR was set in the program to start at 12 a.m. instead of 12 p.m. (Noon). I couldn’t figure out why it kept calling the U1400 matches! Hehehehehe.

Thanks for all of the hard work! Your blood, sweat, tears and frustration makes it soooo nice and simple for us. :-D

Charleste King

April 29, 2004

Hi, David.

First, I wanted to thank you for the great program you have created. Using Cantor and the new website is so easy and the players appreciate how in minutes they can view their new ratings. On behalf of them, thank you.

Oleg Zalesskiy

April 25, 2004


We used the new Cantor program and new website for the first time on Sunday, April 25, 2004, for our weekly “Lakeland Sunday Round Robin Spectacular”. As I noted in an earlier email, we have not been keeping game scores, only match wins and losses with the previous system. I was pleasantly surprised at how well our players adapted to the new system. We produced simple match cards for the players to take with them to the tables and a tray to deposit the results at the control desk. The players were excited about the new process and there were no complaints from anyone.

When I arrived home, with the match cards, I quickly processed the results with Cantor. I was very pleased with the minimum amount of time it took to enter the players and game scores. I then went online, set up the email and did a test. I then submitted the results, had a confirmation from Ratings Central about the test and the results that I had submitted. Our new ratings were processed rapidly, and I then emailed the results and the new ratings to all our players. We completed play at our club at 5:45 p.m. and our players had the results and their new ratings before 7:00 p.m.

In conclusion, this is a superior system and I know all our players are excited. As for problems or bugs, there were none that we observed. The system worked flawlessly for us.

Thanks for the great program!!!!

Best wishes,
Raymond D. Spann
Lakeland Table Tennis Association

March 31, 2004

Hi, David.

Thank you for showing me Zermelo when I was at the Boston club. The software is easy to use and the manual explains in detail how to use it. At the Rhode Island tournament, we had an awesome experience using Zermelo. All the staff liked the software and were happy that it reduced the amount of work we had to do this year to organize the event.

Mohamad Al-Sabek

February 22, 2004


I was asked to run the ACUI Region 15’s Table Tennis tournament at UC Davis this last weekend. I used Zermelo. …

Anyway, all went well—there were 5 women and 24 men. Since I was the tournament director and umpire/referee I was called to the floor a lot, so my 11 year old daughter was able to run the program to enter results and print the call sheets. With 6 tables, 4 groups of 6 RR, then advancing 2 from each group to SE, we finished the tournament in 4 hours. Wonderful program!

Again, thanks for a great program. Organizations from a few schools were interested in the program when they saw me using it. They are all using either a spreadsheet or not using a computer at all in their school TT club or intramural tournaments.

Yau-Man Chan

December 6, 2003


[I used] Zermelo for the Univ. of California, Berkeley, Associated Student Union Center tournament. This was a really strange one, as was how I got involved. Evidently, the Student Union advertised this “ping pong” tournament with fliers in all the dorms, frat, and co-op houses around the campus, but I didn’t know about it. The 1st prize was $150, 2nd $75, and 3rd $50—a lot of money for students. I found out about it when I happened by the Rec. Center and they were getting ready to start and a huge “discussion” ensued. The organizer had no clue how to run a TT tournament, 90% of the players only knew the ping-pong version of the game. A few players insisted on playing with 40 mm balls and under proper TT rules; that was what the whole discussion was about. So, when I happened by, prompted by a few TT players there that I knew, I volunteered my service as a certified USATT Club Umpire and offered to explain the rules and help the organizer run the tournament—if they can start 15 minutes later so I can go to my office and get my laptop and printer. We got everyone to agree to play by USATT rules (except dress code), and I had enough 40 mm 3-star balls in the trunk of my car!

So, I ran a totally impromptu tournament with Zermelo. It took no more than 10 minutes to enter all the names (30), set up the event, print the draw, and call players. We had 6 groups of 5, with 2 advancing to single elimination. I set it up to play 2 of 3 for the RR and 3 of 5 for the SE rounds. With 30 players, we finished in 4.5 hours.

Yau-Man Chan

Devil to Play” by Eric Dexheimer, Denver Westword, July 1, 1999.

This article is about the U.S. Tennis Association’s league ratings.