September 24, 2023. Ratings Central has been providing table tennis ratings for clubs, organizations, and countries around the world since 2004. The database contains over 110,000 players and 4.9 million matches. The Bayesian rating algorithm (in the same family as the Elo, Glicko, and Glicko-2 algorithms) uses a normal mean-zero random walk to model how a player’s playing strength changes in time. In 2018, our largest user, the Austrian Table Tennis Association, noticed deflation of 30 to 40 points per year for players who had been playing for a decade. Also, rapidly-improving players (typically juniors) were sometimes underrated. Fixing the priors that the Austrian Table Tennis Association had used reduced the deflation to 10 points per year. To fix the remaining problems, I modified the temporal-update model by adding a Poisson jump process with jumps of 200 rating points. I set the probability that a jump occurred so that the mean of the temporal update was +7 rating points a year. The algorithm is implemented by discretizing the probability distributions. In my investigation, I used simulation and scoring rules. However, most helpful were graphs of the rating history of individual players and also scatter plots showing the rating change between a player’s first and last event versus the time between the two events. Ratings Central started using the improved temporal update model in 2019. All historical data was reprocessed using the new model. For future work, I present an algorithm for rating individual doubles players.
Review of Quantum Sense and Nonsense by Jean Bricmont, May 17, 2020.
eLetter to the Editor on the news article Quantum weirdness confirmed by Adrian Cho (scroll to the bottom of the page to see the eLetter)
News article: Science Magazine, vol. 350, issue 6267, p. 1463, Dec. 18, 2015; article requires subscription to access on website. eLetter published Feb. 19, 2016; eLetter can be accessed on Science Magazine website without subscription.
Letter to the Editor on Bell’s Theorem and the Demise of Local Reality by Stephen McAdam
The American Mathematical Monthly, vol. 111, no. 5, pp. 456–457, May 2004.
Discussion of several well-known paradoxes whose correct resolutions are not well known. The paradoxes discussed are the Liar Paradox, the Prisoner’s Dilemma, Newcomb’s Paradox, Is It Rational to Vote?, and the Unexpected Hanging. September 11, 2016; revised June 27, 2017, May 6, 2018, November 14, 2020.
What happened at the Tournaments of Champions (TOC), June 8, 1990–June 17, 1990. The TOC consisted of the Fifth World Veterans Championships, the 1990 U.S. Open, and the International Junior Championships. Article written August 21, 1990, and published in the USATT magazine that year.
Another antidote to the nonsense of the usual explanations of quantum mechanics. More technical than the author’s Quantum Sense and Nonsense. Read them both.
A must-read book on programming (regardless of whether you use Pascal).
Ratings
Devil to Play by Eric Dexheimer, Westword, July 1, 1999
Denver Tennis Club’s 4.5 men’s team.
Technology
Collision Course by T. Christian Miller, Megan Rose, Robert Faturechi, Agnes Chang, Pro Publica, December 20, 2019
When the USS John S. McCain crashed in the Pacific, the Navy blamed the destroyer’s crew for the loss of 10 sailors. The truth is the Navy’s flawed technology set the McCain up for disaster.
Some organizations seem to have purged “human error”, operating highly complex and hazardous technological systems essentially without mistakes. How do they do it?
Psychology
The Nurturing Parent by John S. Dacey, Ph.D., and Alex J. Packer, Ph.D., Child, November 1992, pp. 96, 107–109, 112–113, 216
6 Ways to Make Your Child Happy (and why they work).
Proverbs
Hanlon’s Razor: Never attribute to malice that which can be adequately explained by stupidity.
