Jeff Sonas is a software engineer and database consultant who is also one of the world’s leading experts on chess ratings. As you may have read, FIDE recently proposed some changes to its rating system (partially due to Jeff’s advice). . In our conversation, Jeff explains the background of his work on ratings, and why he feels that changes to the system are necessary. Following a detailed and fascinating conversation about chess ratings, we discuss Jeff’s excellent historical chess site, Chessmetrics.com, which compares the relative strength of top chess players across eras. Due to his expertise on the topic, I also invited FM Nate Solon to co-host this episode. Nate writes about chess and data on his excellent blog, Zwischenzug.As always, you can find timestamps of topics discussed below.  Sign up for my newsletter, The Perpetual Chess Linkfest here:  https://benjohnson.substack.com FIDE Press release about Proposed Rating Changes- https://fide.com/news/2538 Jeff’s paper-  https://www.fide.com/docs/presentations/Sonas%20Proposal%20-%20Repairing%20the%20FIDE%20Standard%20Elo%20Rating%20System.pdf NM Vanessa West's Summary of the Proposed Changes: https://www.chess.com/news/view/fide-mathematician-proposes-changes-to-improve-rating-accuracy Thanks to our presenting chess education sponsors, Chessable. Here are some courses to check out FM Nate Solon’s course here: 100 Repertoires: Reti (1.Nf3)  You can check out some of my recommended courses here: https://go.chessable.com/perpetual-chess-podcast/ 04:00- We welcome Jeff Sonas to the show!  04:30- He begins by discussing the history of his work in ratings, and specifically with FIDE. Jeff also discusses how he has gone from worrying about inflation to deflation? Mentioned: Rating Inflation: Its causes and Its possible cures  26:00- Patreon mailbag question- Could Jeff put a number on the amount of deflation? Is there deflation on the chess playing websites?  36:00- More explanation of the causes of deflation  Mentioned: GM Jacob Aagaard’s Tweet, Article by Tarjei Svensen about Velpula Sarayu’s Record Performance  42:00- Does the deflation matter, other than for reasons of vanity?   48:00- What does Jeff think of the Glicko system?  Episode 249 with Dr. Mark Glickman, Jeff’s Archive of Chess Writing  53:00 Patreon mailbag question: How feasible is a universal rating system based on engine move matching?  Mentioned: Read Jeff’s paper here: https://www.fide.com/docs/presentations/Sonas%20Proposal%20-%20Repairing%20the%20FIDE%20Standard%20Elo%20Rating%20System.pdf 59:00- Jeff discusses the history and methodology of his awesome chess history website, Chessmetrics Mentioned: Jeff’s Series: Who is the Greatest Player of All Time  1:10:00- Where would Carlsen rank? 1:14:00- What would be the biggest challenge to creating a chess site similar to a basketball reference or ultimate tennis statistics?  1:16:00- Has Jeff ever gotten inquiries about his data from top players? Mentioned: Chess24 top 50 of all time Series with GM Jan Gustafsson and GM Peter Heine Nielsen  1:18:00- Which historical player is underrated?  1:25:00- What is Jeff’s own chess background?  1:28:00-  Thanks so much to Jeff for joining the podcast! You can reach him via the Chessmetrics website: http://www.chessmetrics.com/cm/CM2/Introduction.asp And be sure to subscribe to FM Nate Solon’s free blog here: https://zwischenzug.substack.com/ Learn more about your ad choices. Visit podcastchoices.com/adchoices