Approximate ELO

I think that's a good idea, and is something David Alves had slated for roborumble.org =), but everyone else's ratings would still change as the population changes, just as APS does. I was just saying that is unavoidable, and not an anomalous side-effect of some weird scoring formula, like ELO rating drift.

Avoiding ratings drifts due to population increase is hard to workaround, and the anchor competitor is the only way I know.

But avoiding ratings drifts due to re-submits (everyone´s rating going down) can be avoided by centering everyone around a constant number, like 1600, or around a single anchor competitor.

If I had to pick an anchor, I would go with something like SandboxDT, RaikoMX or some other classic robot.