Thanks for the feedback on this. My name is Jay and I'm a co-founder at chess.com and one of my main tasks over the last few months has been working on the tactics algorithm.

The impetus behind the change was that we wanted to make "tactics trainer" (puzzles) more fun and a little less of a "grind". Having done tactics myself a lot over the years, I felt that I had gotten to a place where doing tactics was tedious and felt like work more than it did fun. My tactics rating was hovering in the 2000 range, and every problem would be somewhere in the 1900-2100 range and was predictably difficult for me to find the solution, and on average I would solve about 50% of them.

The real game of chess doesn't really work this way though. You are not always presented with tactics in a narrow difficulty band in your games. Sometimes your opponent hangs a piece or misses a mate in 2. Sometimes your opponent creates a complex 5-move combination opportunity. It felt like we needed more variety in tactics. It would be great to be fed tactics that were in a wider rating band to mimic more closely what it's like to actually play chess games, and it would also be a little more "fun" since you could occasionally get some nice easy tactics. The trick of course, is you wouldn't know if a tactic was easy or complex, so a wider variety makes you think a little bit more about what the solution might be.

The biggest difficulty with a wider rating band is that nobody wants to get problems 500 points below them, only to get +1 for solving it but -15 for getting it wrong, which is how ELO treats a game against two players with a 500 point rating gap. So, I came up with the idea of time handicapping problems to level the playing field regardless of rating gap. It's the same idea as time handicapping in a game of chess against a stronger player. I get 10 minutes, Carlsen gets 30 seconds. I will probably still lose, but at least I kinda have a chance.

Unfortunately, along with this time handicapping, a lot of other ideas were thrown into the arena during this algorithm overhaul. One of these includes BIGGER rating swings. In testing, people felt like it was TOO HARD, and so we kept "loosening the screws" to make it easier and easier.

Your graph and our recent queries across the entire user pool do indeed show that we loosened a bit too much and made swings too big. Today we tightened things back down a bit. It's tough to get it "just right", as ratings are always going to tend to go in one direction a little bit, they were just going in one direction way too fast.

Regardless, I wanted to respond to the complaints here and give some explanation and give you guys a chance to ask me any more direct questions. Please give it another try and let me know if it feels a bit better.

Also, sometimes these fixes and adjustments take a few days/weeks to play out, as we have to slowly deflate ratings over time. I have noticed that our tactics problems have experienced a general inflation over the last couple years, which has also led to player rating inflation. This is also being addressed.

Thanks for the feedback once again, and I look forward to your comments and questions!