> With MTG, you have a huge effect from the quality of the deck. Unless you have each player play with each deck, there's no way to de-convolute the quality of the deck vs the quality of the player. And if you did have that data, Elo couldn't leverage it -- you'd need a more sophisticated model to account for that statistical effect.
How well a player chooses their deck is one of the factors that determines how good a player is. You can say the same thing about the other games: I'd probably have a better rating in chess if I didn't only play somewhat unsound gambits, and I'd definitely have a better rating in Starcraft if I didn't only do 2port wraith in TvZ.
A deck is something you have. A build order, or a chess opening, is something you _know_ and therefore more or less what I'd be comfortable calling skill.
In my experience playing MTG (and other card games), when players discuss skill, they generally mean a (somewhat fuzzy) combination of both deckbuilding and "piloting" ability. It's understandable to want to draw a line between the two and say "I only want to evaluate in-game decision-making,", but, not only is that wildly impractical (it's going to be really hard to develop a model which fairly accounts for the fact that your buddy Jeff only likes playing decks which do nothing for 50 turns and then win the game on the spot iff no one else has a counterspell[0]), part of the way card game leagues work (again, in my experience) is that players spend a lot of time trying to figure out how to make their decks better and adapt them to what other players are doing. If you can't capture that effort, I honestly think you might be missing the point a little bit.
[0] Let's be clear, Jeff's deck is bad and he's going to lose a lot, even if he's a time-traveling supercomputer with the diplomatic finesse of Otto von Bismarck.
> when players discuss skill, they generally mean a (somewhat fuzzy) combination of both deckbuilding and "piloting" ability.
I think the "piloting" ability is mostly (but not entirely) independent of the deck. You can see this most plainly in draft, where everyone is basically playing with a new deck. There are "soft" skills that are contextual and format-dependent, like knowing the cards that you need to play around (white just foretold turn 2, is that a Doomskar? Maybe I shouldn't play a creature this turn, etc). There are "hard" skills that are almost always valid (generally wait until after combat to spend mana, cast instants during your opponent's end step, etc).
But certainly deckbuilding talent is not necessary, because anybody can grab a decklist and head to TCGPlayer.
On that note I'd guess that draft (or sealed) tournaments are the best scenario to measure pure skill using Elo alone, since going into a tournament, everyone has equal chance to open good cards.
Beyond a certain level, everyone has access to all the cards they want. That might cause a poor fit on the bottom levels, but intermediate to advanced levels, its not about ownership
That’s a fair point for Commander. But the GP seemed to be making a universal claim that ELO wouldn’t make sense in any case, even say Standard where the decks are <$500 (or Arena where you can get a meta deck for <$100, free if you have time to grind wildcards).
I think perhaps we could agree on an intermediate claim that Elo could work amongst the pool of players that can build any deck they want, which is a big pool for MTGA, and definitely a smaller pool for physical Standard, and probably very small for Commander.
I wonder if you could decompose the score by playing some games with a fixed deck too? Eg Arena challenges. How much of your overall Elo is just picking the right deck for the local meta, vs raw quality of plays?
That depends fully on the format. Original article doesn't specify afaik, but the only sanctioned commander games I've ever played in a tournament format were limited events
MtG is like car racing. Sure, most people own cars (hi from California) and can theoretically race them. But anyone any good at racing has a lot of money.
How well a player chooses their deck is one of the factors that determines how good a player is. You can say the same thing about the other games: I'd probably have a better rating in chess if I didn't only play somewhat unsound gambits, and I'd definitely have a better rating in Starcraft if I didn't only do 2port wraith in TvZ.