Approximate ELO

Does it currently do that? The Glinko-2 has drifted up, the 2000 club now consists of only the top 16 bots.

Which is why I was considering trying to make a Approximate version. However, with mine instead of drifting down I think I see higher bots drifting up, and lower bots drifting even more down. I think this is because as new lower bots are added the APS for higher robots go up, and robots that did worse against it go down.

So it faces an entirely different kind of drift, but at least the center seems stable.

ELO/Glicko-2 work with differences between ratings.

The more competitors the ranking has, the more the rating difference between first and last places will be. This is normal.

But ELO has another drifting problem due to deflation. All competitors ratings going down because most retired competitors have ratings above the average.