Rating floor

How about having a floor beyond which someone can't drop? I'm currently playing someone who is currently rated 900 points lower than their highest rating. Obviously resigning dozens of games skews rating not just for themself but for everyone they play and the tournaments they qualify for. How about not being able to drop more than, say, 200 points below your highest rating?

You can't allow the floor as the ranking is partly average and partly formula. When a player first starts out, their ranking will fluctuate wildly until it starts to average out due to the number of games. Then, the win loss ratio is adjusted for the rank they are playing at as well as the rank they are playing against. It would also be unfair as the person could lose umpteen games, maybe even deliberately, and the floor would prevent that from being reflected in the ranking. Ya gotta earn it.

Ratings measure a player's current strength, not how strong they once were.

"Ratings measure a player's current strength, not how strong they once were."

Playing 250 games simultaneously and then resigning 50 of them after a handful of moves, doesn't mean that you are now 500 points weaker than you were 10 minutes ago. It just means you've manipulated your rating. Obviously this can work in the reverse direction too.

I'm sure it could be more sophisticated than highest-200, perhaps based on average opponent strength, excluding games under N moves, and only kicking in if your RD is below X and # games > Y or whatever. But I do think that wild swings in ratings should be mitigated against.

No it isn't you actually. You only dropped 500 points :)

Rating floors are not a bad idea, but difficult to implement on an Internet site due to the staggering number of games played.  In practice, a player's typical rating will not change enough by "sandbagging" (intentional loss) to reflect a statistically significant difference in ability.  Any subsequent win will put them right back at the pre-sandbagging level (sometimes even higher).  It's not clear what the effects of age are on peak rating, although it makes sense that ranking would decrease based on a decline in game load and the evolution of player skill.  

 However, you would be sorely mistaken to believe that veteran players somehow lose Chess knowledge as they age.

Many of the big fluctuations are due to someone who is playing hundreds of games and forgets/can't log in and play them in time. There's no point to resigning lots of games, since there is no prize money involved here...that I know of.

Some kind of floor would stop that wild fluctuation.

So, I can see people playing hundreds of games and not caring if they time out or even resign a few dozen when they are feeling like it because they are protected by rating floor.