Life In 19x19

I think McMahon is a really good tournament system, it usually breaks when people don't understand how to implement it.

If you have a very small pool of players, sometimes it doesn't work that well, but I'd struggle to see what you could replace it with. For instance take a field like this over 5 rounds - 6D , 6D, 1K, 2K, 5K, 12K, 12K, 12K, 13K, 15K, 15K, 2K, 22K

It does seem interesting to experiment with using larger bands below the bar, but that's never caught on in the UK. I suggested using that to expand the number of players who could take part in the Candidates Tournament, but nobody agreed with me, and some people just mocked the idea that you could even think to do that.

Actually in Fenrings's example I don't think it's possible for A to end up with less points than B. D has at least 1 point, B has 2 points, A has 3 points, 1+2+3=6. E has 1 point at most, F 1 point at most, and B has 2 points. 1+1+2=4 points. So it's not possible for A to lose.

I'm also thinking of a completely different idea!

Use McMahon for pairing only, with the results determined based on the Sum Of Defeated Opponent's Score's: each players opponents are ordered from the player with the highest McMahon to the lowest. The McMahon of each opponent is divided by the number of their rank down the list, and then the divided scores are added up to get the adjusted SODOS which determines the winner!!!

edit: I definitely think that the correct way to use McMahon is the prioritise the SODOS and SODOSODOS and so on, ignoring SOS which is useless in McMahon but useful for Swiss. SOS doesn't make any sense whatsoever as a tiebreaker in McMahon. SOS is for Swiss tournaments. The entire point of McMahon is essentially to replace the need for SOS or SOSOS and use SODOS and SODOSODOS instead. The main function of McMahon is to preset people's SOS according to their rank that represents the previous average level of their play. Which means SOS is terrible at scoring for people who do very well on the day or have an off-day. SOS works for Swiss tournaments where you might randomly meet opponents of very different rank in the early rounds, but in McMahon it's the opposite so SOS has a negative effect in deciding the points. Here SODOS is the obvious choice instead, haha !

Fenring wrote:And i don't know why this system is not in the european rating system.

Inertia, I suppose. I think that such a change would need to be called for by some bid in the AGM, which requires some determined people that are backed by some EGF member countries.
The 2021 update of the European rating system took almost 2 years from proposal to implementation.