Ivecseen many posters say that fetchlands thin your deck, and many say the opposite. Those that say it doesn't, have mathematics backed by this claim, but an average Joe like myself just don't see it. I'm bad at math, but one land that fetches another land out of you deck means that there's now one extra land removed. What am I missing?
It takes something like 8 fetches to have any relevant level of thinning. For RDW/Boros, it would usually only be relevant for Landfall. In some formats, where control or Tempo mirrors can go long, it can be hugely relevant to improve your top-decks by thinning it down.
Tl;Dr: depends on the deck, length of game, and # of fetches cracked.
Nobody is saying that they don't thin out your deck - what the math is suggesting is that it doesn't make a significant impact until you remove more than just 1-2 lands in your deck.
There are reasons to run fetchlands in your (monocolour) deck other than simply thinning your library such as landfall triggers or reshuffling to take advantage of library manipulation (Sensei's Divining Top, Brainstorm).
If I understand correctly the mathematical arguments are often based on the fact that the life loss from the fetchlands is a far greater percentage of you life than the decreased chance of hiting land.
...not only is the total number of players expanding very quickly, but at the same time a greater and greater number of those players are being pushed to only desire a small subset of the available cards. These combined forces drastically increase demand for those cards and cause the values of just those specific cards to often balloon out of proportion.
Thinning your deck of a single land via fetching gives you a benefit that is not worth the 1 life. Basically, it's the same as what would happen if you left the land in your deck, but it gained "cycling 0". The chance that you draw that land is equal to the fraction of your deck that you draw over the rest of the game.
So if you figure that the average game lasts 10 turns, and you fetch on the first turn, you are paying 1 life to draw an average of 1/4 of a card. Except you don't get the card right away. You get it later. If you draw your fetch on the 5th turn, you get only 1/8 of a card -- and again, if you do get the card, you don't get it right away.
Paying 1 life for even 1/4 of a card, let alone 1/8, is a very steep price and is not worth paying unless you know that your opponent will not be putting pressure on your life total.
I would think running fetches would screw up your calculation of mana ratios in a deck due to being a land that removes lands from it. Sort of like why Mox Diamond has to be counted as non-mana.
What kind of deck are you playing? The archetype will determine how much single points of life at a time are worth to you.
How desperate are you to thin your deck? The advantage, it's true, is likely to be miniscule, but sometimes miniscule differences are what win games (or lose them, it's true). The very idea that you are thinning your deck and improving your chances of drawing into relevance can give you a beneficial psychological advantage over your opponent, which cannot be discounted.
How many fetchlands and regular lands are you using? If you're only using 8 fetches and 8 Plains (Craig Wescoe ALA/ZEN White Weenie), you can bet your ass you're gonna see a much bigger impact than if you have 2 Scalding Tarns in a control list. One of my issues with the most frequently cited study on fetchland thinning, which is used to disprove thinning, is that the test only uses, if I recall correctly, one generic deck type, with 40 lands and 20 spells with no external factors. Obviously, it's useful as an example, but that doesn't mean it disproves all cases in which you'd want to use fetches for thinning.
That brings me to the next question: what else is in your deck (part 1)? Fetchland thinning will become more relevant to decks that are using other methods, like Cultivate or Primeval Titan.
And, what else is in your deck (part 2)? There's really no single answer to the question "does fetchland thinning work?" What else will fetchlands synergize with (Lotus Cobra? Jace, the Mind Sculptor?)? Fetchland thinning could, hypothetically, be the tipping point between using fetchlands and some other kind of land.
In the end, it's mostly a matter of personal opinion, because it's only the sort of thing that can be determined on a list-by-list basis.
Ah, so it does thin the deck, but it isn't worth it in some cases as it doesn't seem to be much of a relevance for all decks?
It does thin the deck but it thins the deck an extremely negligible amount and though 1 life is no big deal it is worth something.
Fetchlands are worth it in multicolored decks and decks that want shuffle effects, landfall, or something else other than thinning that fetches provide. So they're still worth it in decks like High Tide or RDW with Grim Lavamancers and Plated Geopedes.
The thinning is negligible if you're only popping a couple fetches, but is still nonzero. If you're planning on winning in the first 5 turns, then mana fixing is what you're going for. Or landfall triggers.
I think "thinning" worked pretty well in this particular instance. To be fair, I might have gotten the same draws without thinning.
Anecdotal evidence is largely irrelevant when your talking about such a small change to something with an already high variance. The reason running fetches only for deck thinning is bad is that you are significantly more like to lose from spending extra life than you are from drawing <1 extra land over the course of the game.
Also, fetches are run in solidarity not because it thins your deck but because it is a shuffle effect for brainstorm. Yeah the thinning kind of helps but it is largely irrelevant.
Here's some real quick napkin math on thinning with fetches: assume:
24 land/60 card deck
your opening hand is 3 land 4 spells
you're on the draw
when you draw a card you draw a portion of a land and a portion of a spell such that the ratio of lands:spells does not change.
Fetch on T1
T1: 39.6% chance of drawing a land. Fetch.
T2: 38.4% chance of drawing a land.
Fetch on T1 and T2
T1: 39.6% chance of drawing a land. Fetch.
T2: 38.4% chance of drawing a land. Fetch
T3: 37.2% chance of drawing a land.
In the first case you're paying 1 life to decrease your chance of drawing a land by only 1.2%. In the second case you end up with a 2.4% increase for 2 life but that still doesn't sound that great to me.
E- I double checked my math and I was slightly off (read about .5%).
Anecdotal evidence is largely irrelevant when your talking about such a small change to something with an already high variance. The reason running fetches only for deck thinning is bad is that you are significantly more like to lose from spending extra life than you are from drawing <1 extra land over the course of the game.
Also, fetches are run in solidarity not because it thins your deck but because it is a shuffle effect for brainstorm. Yeah the thinning kind of helps but it is largely irrelevant.
Here's some real quick napkin math on thinning with fetches: assume:
24 land/60 card deck
your opening hand is 3 land 4 spells
you're on the draw
when you draw a card you draw a portion of a land and a portion of a spell such that the ratio of lands:spells does not change.
Fetch on T1
T1: 39.6% chance of drawing a land. Fetch.
T2: 38.9% chance of drawing a land.
Fetch on T1 and T2
T1: 39.6% chance of drawing a land. Fetch.
T2: 38.9% chance of drawing a land. Fetch
T3: 36.6% chance of drawing a land.
In the first case you're paying 1 life to decrease your chance of drawing a land by only 0.7%. In the second case you end up with a 3% increase for 2 life but that still doesn't sound that great to me.
Basically this. A number of years ago, an article on the subject was written over on TCGPlayer. Here it is (warning: contains math):
It fails to meet the criterion of "are you more likely to win the game after using this ability than you would if it were just a basic".
Now, to be fair, I don't have a ton of data on this. But it is a factual assertion. I think it's true, and I've explained why I think that using the heuristic argument that you're probably paying 1 life for 1/4 of a card or less.
Fetchland thinning will become more relevant to decks that are using other methods, like Cultivate or Primeval Titan.
This is incorrect, unless what you're trying to say is that removing more land will thin your deck more (which is obvious). Removing one land from your deck will always have the same effect, no matter how many other lands you remove by other means*. Playing Cultivate does not make playing fetchlands better.
*Technically your total deck size will be smaller, so the removal of one additional land will have slightly bigger effect than usual, but that's negligible.
Basically, if you're playing control, that one life can make a huge difference in a game against an aggro deck, and more land doesn't hurt you as badly anyway. If you're playing aggro, usually you've basically lost the game if you go past turn 5 or 6 anyway, so you're only going to see one extra nonland card every ten games or so (assuming you fetch early on in each game). One extra card is simply not worth 10 life.
We've done this before. If you're really interested in reading the same arguments that have been made over and over since the creation of the original fetchlands, please feel free to use the Search function. Thread closed.
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Tl;Dr: depends on the deck, length of game, and # of fetches cracked.
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There are reasons to run fetchlands in your (monocolour) deck other than simply thinning your library such as landfall triggers or reshuffling to take advantage of library manipulation (Sensei's Divining Top, Brainstorm).
So if you figure that the average game lasts 10 turns, and you fetch on the first turn, you are paying 1 life to draw an average of 1/4 of a card. Except you don't get the card right away. You get it later. If you draw your fetch on the 5th turn, you get only 1/8 of a card -- and again, if you do get the card, you don't get it right away.
Paying 1 life for even 1/4 of a card, let alone 1/8, is a very steep price and is not worth paying unless you know that your opponent will not be putting pressure on your life total.
What kind of deck are you playing? The archetype will determine how much single points of life at a time are worth to you.
How desperate are you to thin your deck? The advantage, it's true, is likely to be miniscule, but sometimes miniscule differences are what win games (or lose them, it's true). The very idea that you are thinning your deck and improving your chances of drawing into relevance can give you a beneficial psychological advantage over your opponent, which cannot be discounted.
How many fetchlands and regular lands are you using? If you're only using 8 fetches and 8 Plains (Craig Wescoe ALA/ZEN White Weenie), you can bet your ass you're gonna see a much bigger impact than if you have 2 Scalding Tarns in a control list. One of my issues with the most frequently cited study on fetchland thinning, which is used to disprove thinning, is that the test only uses, if I recall correctly, one generic deck type, with 40 lands and 20 spells with no external factors. Obviously, it's useful as an example, but that doesn't mean it disproves all cases in which you'd want to use fetches for thinning.
That brings me to the next question: what else is in your deck (part 1)? Fetchland thinning will become more relevant to decks that are using other methods, like Cultivate or Primeval Titan.
And, what else is in your deck (part 2)? There's really no single answer to the question "does fetchland thinning work?" What else will fetchlands synergize with (Lotus Cobra? Jace, the Mind Sculptor?)? Fetchland thinning could, hypothetically, be the tipping point between using fetchlands and some other kind of land.
In the end, it's mostly a matter of personal opinion, because it's only the sort of thing that can be determined on a list-by-list basis.
That's an opinion, influenced by many factors, not a fact.
I use fetches to thin my deck, since I have lost FAR more games due to late game mana flood than losing 2-3 life from the fetches.
It does thin the deck but it thins the deck an extremely negligible amount and though 1 life is no big deal it is worth something.
Fetchlands are worth it in multicolored decks and decks that want shuffle effects, landfall, or something else other than thinning that fetches provide. So they're still worth it in decks like High Tide or RDW with Grim Lavamancers and Plated Geopedes.
Anecdotal evidence is largely irrelevant when your talking about such a small change to something with an already high variance. The reason running fetches only for deck thinning is bad is that you are significantly more like to lose from spending extra life than you are from drawing <1 extra land over the course of the game.
Also, fetches are run in solidarity not because it thins your deck but because it is a shuffle effect for brainstorm. Yeah the thinning kind of helps but it is largely irrelevant.
Here's some real quick napkin math on thinning with fetches:
assume:
In the first case you're paying 1 life to decrease your chance of drawing a land by only 1.2%. In the second case you end up with a 2.4% increase for 2 life but that still doesn't sound that great to me.
E- I double checked my math and I was slightly off (read about .5%).
Basically this. A number of years ago, an article on the subject was written over on TCGPlayer. Here it is (warning: contains math):
http://magic.tcgplayer.com/db/print.asp?ID=3096
Play (verb): Cast/Play
RFG: Exile
CIP: Enters the Battlefield
Fetchland: Arid Mesa
Shockland: Watery Grave
M10 Dual: Glacial Fortress
So which objective criteria for what a life point is worth does a fetchland fail to meet, then?
Now, to be fair, I don't have a ton of data on this. But it is a factual assertion. I think it's true, and I've explained why I think that using the heuristic argument that you're probably paying 1 life for 1/4 of a card or less.
This is incorrect, unless what you're trying to say is that removing more land will thin your deck more (which is obvious). Removing one land from your deck will always have the same effect, no matter how many other lands you remove by other means*. Playing Cultivate does not make playing fetchlands better.
*Technically your total deck size will be smaller, so the removal of one additional land will have slightly bigger effect than usual, but that's negligible.
Basically, if you're playing control, that one life can make a huge difference in a game against an aggro deck, and more land doesn't hurt you as badly anyway. If you're playing aggro, usually you've basically lost the game if you go past turn 5 or 6 anyway, so you're only going to see one extra nonland card every ten games or so (assuming you fetch early on in each game). One extra card is simply not worth 10 life.