Could you raise your score arbitarily high by only playing against much weaker opponents?

Question

Obviously the community would accept or acknowledge such a hack ... but mathematically would it work, or does the Elo system have something to prevent this?

My impression is that, very roughly speaking each time you play someone, your Elo goes up or down depending on whether you win. And how much it goes up or down depends on the disparity between your previous rating and your opponents.

• If you beat someone who was better than you it goes up a bunch.
• If you beat someone who was a little bit worse than you, it goes up a little.
• If you beat someone who was very much worse than you, it goes up a tiny amount.

But I assume that even if you play people who were ridiculously worse than you ... is still goes up a bit?

So could you hack your "rating" by playing tons of games against people who are much worse than you ... such that you'll never lose, and your rating will keep going up and up, even though you're not getting any better?

Answer 1

So could you hack your "rating" by playing tons of games against people who are much worse than you ... such that you'll never lose

No. If you play enough games you will lose some and draw some and every draw will lose a ton of points and a loss will lose even more. The ratings calculation tables are based on statistics so that expected ratings gains and losses correspond to the probabilities of players with the given rating difference winning, drawing or losing.

See also this related question.

Answer 2

1. Rating calculations are done while keeping a few things in mind to avoid these kinds of hacks. If you play a very low-rated player for a number of games then there'll be a point there'll be no rating gain. Just zero points for a win
2. There are chances that you might end up losing/drawing a game as your opponent will understand your game plan/strategy. This will cost you a lot of ratings.
3. If you play weak players consistently then your game will not improve and may even become worse.

Answer 3

Yes, with a "pure" Elo system, you could, theoretically, increase your Elo arbitrarily large. There are three caveats:

1. Each organization uses a different versions of the Elo system, and they may very well have a modification, such as having a cutoff after which you don't receive any Elo gain.

2. While mathematically, there is no upper limit, in practice there's a limit to how many points a person could get before they died of old age.

3. Winning 100% of the time, not just 99.99%, isn't necessarily possible. I'm reminded of "Man from the South" by Roald Dahl https://en.wikipedia.org/wiki/Man_from_the_South :

While vacationing at a resort in Jamaica, the narrator encounters an elderly South American man named Carlos. They are soon joined by a young American naval cadet, who boasts about the reliability of his cigarette lighter. Carlos offers to bet his Cadillac against the American's left little finger that the American cannot ignite the lighter ten times in a row.

The tension comes from the fact that no matter how easy something is, can you really be sure that you won't mess it up somehow?