There doesn't seem to be anywhere on the web that clearly indicates the odds of each type of card appearing in a pack, including foils.
From what I can gather, this is what the normal probability should be (for a pack of a non-Innistrad-related standard set):
Basic Lands: 1
Commons: 10 - Odds of Foil
Uncommons: 3
Rares: 7/8
Mythics: 1/8
Many places list the likelihood of a Mythic in the rare slot being 1 in 8. However, when you looks at [url=http://boardgames.stackexchange.com/questions/12149/what-chance-do-i-have-of-my-foil-being-a-rare-or-mythic]an uncut sheet[/url], it looks like there are 2 copies of a rare for each Mythic for foils at least. This ends up being close to 1/8, but not exactly.
e.g. Kaladesh
53 rares
15 mythics
Sheet would have 53 * 2 + 15 = 121 cards (matching an 11 x 11 sheet), making the odds of a mythic 15/121, or 12.4% (slightly less than 1 in 8). For a set like Aether Revolt, this would be 42 * 2 + 12 = 96 (which doesn't make a nice square number for sheets), with the odds being 12/96, or exactly 1/8 like the assumption.
What's even more complex is foil frequency. The most specific information I can find is [url=http://www.mtgsalvation.com/forums/magic-fundamentals/magic-general/325533-how-do-booster-pack-foils-work?comment=6]this post[/url] which gives the following odds:
15/63 packs has a foil
It also gives odds as follows for each foil card:
11/16 commons
3/16 uncommons
7/128 rares
1/128 mythics
1/16 basic lands
This runs in to the same assumption about mythics being 1/8 of the rares. It also is old, and there are many posts here and there saying that foils used to be 1/4 packs (close to the 15/63 listed in the linked post), but are now closer to 1/6 packs. Take [url=https://www.mtggoldfish.com/articles/the-expected-value-of-kaladesh]Seth, probably better known as SaffronOlive's KLD EV article[/url] (math is number of foils per box):
3 commons
2 uncommons
1 rare
1 mythic every 8 boxes
This comes out to 6.125 foils/36 packs, or the 1/6 assumption out there. However, the odds of a common end up being only half that of an uncommon -- what makes the foil uncommons so much more common than their non-foil counterparts?
Looking at the numbers of cards in the set (including basics) for KLD, it looks like the foil list for non-rare/mythics is:
1 of each common (101)
1 of each uncommon (101 + 80)
1 of each basic land (101 + 80 + 15)
= 196 = 14^2
But again, this doesn't work so well with AER:
1 of each common (70)
1 of each uncommon (70 + 60)
= 130 = 11.4^2
(Maybe this is related to the lack of a basic land slot in smaller sets? I wouldn't think that would change the size of a foil sheet though...)
If it is some combination of commons + uncommons + basic lands all tossed on a single sheet, then we'd end up with about equal number of foil uncommons to foil commons (since there are usually a similar number). This would seem to not match up well with what Seth is saying for distribution. On the other hand, it looks like Seth's distribution comes from [url=http://www.starcitygames.com/magic/misc/17092-Insider-Trading-Fifteen-Fun-Facts-About-Foils.html]a defunct website called Crystal Keep from 2009 or earlier] since it's used in an SCG article from that time saying the same thing:
6) According to Crystalkeep.com, there's a 1/12 chance of getting a foil Common in a pack of Conflux, 1/18 of an Uncommon, and 1/36 of a Rare. That would average 6 foils per box (3 Commons, 2 Uncommons, 1 Rare). Foil Mythic rares appear about one out of every 216 packs, or once per Case. So if you wanted to open up a Foil Mythic set of Conflux rares, without duplication, you'd statistically have to open a minimum of 2160 packs (or 60 boxes of product!)
For reference, Conflux's distribution was:
60 commons
40 uncommons
35 rares
10 mythics
So that would seem to suggest that it is commons + uncommons on a single sheet, since that would make the odds 2:3 uncommon:common, which is the same as 1/18 vs. 1/12. To broaden that out to include the rares as well we'd get:
Foil Common: 6/72 = 3/36 (3 per box)
Foil Uncommon: 4/72 = 2/36 (2 per box)
Foil Rare/Mythic: 2/72 = 1/36 (1 per box)
If it's a sheet with commons/uncommons, and a sheet with rares/mythics, that would make:
60 commons x 4 = 240 = 240/480 = 50%
40 uncommons x 4 = 160 = 160/480 = 33%
70 rares = 70 = 70 / 480 = 14.6%
10 mythics = 10 = 10 / 480 = 2.1%
This seems to make sense with the odds, so there were (for Conflux at least) probably 4 common/uncommon sheets per rare/mythic sheet.
So if I were to put this together to give an answer to how to most accurately calculate EV for a set, it would be:
Basic Lands: 1
Commons: 10 - Foils (1/6 packs)
Uncommons: 3
Rares: 1 - Mythics
Mythics: # of Mythics in the set / (# of Mythics in the set + 2 x # of Rares in the set)
# of foils to be distributed: 4 x (# of basic lands + # of commons + # of uncommons) + 2 x # of rares + 1 x # of mythics
Foil Basic: 4 x # of basic lands / # of foils / 6 (for the 1 in 6 packs)
Foil Common: 4 x # of commons / # of foils / 6 (for the 1 in 6 packs)
Foil Uncommon: 4 x # of uncommons / # of foils / 6 (for the 1 in 6 packs)
Foil Rare: 2 x # of rares / # of foils / 6 (for the 1 in 6 packs)
Foil Mythic: 1 x # of mythics / # of foils / 6 (for the 1 in 6 packs)
However, I'm a certified moron and almost positive I'm missing something/not doing this right. Does anyone have an authoritative answer on how current sets are distributed in terms of calculating the EV, including foil rarity?
I got lost trying to follow some of that, but it looks like you're making some assumptions that don't line up with what I've heard over the years. I'm not an authority, but this kind of stuff has interested me for a while.
First of all, sheets don't have to be square. I believe that the width is constant at 11 cards due to the machinery involved in printing and cutting. The length used to be 10 cards (which is why many old large sets had 110 of each rarity). As far as I'm aware, sheets are currently 11 cards long, which as you've seen, fits 15 mythics and and 106 rares (2 each of 53) per sheet. However, I am not certain of this.
Commons, uncommons, and basic lands are all printed on separate sheets. Flip card sheets are the exceptions. Shadows Over Innistrad likely mixed commons and uncommons on the same sheet, and original Innistrad likely mixed all rarities on the same sheet.
To handle numbers that don't fit in even multiples on a sheet, several techniques can be used:
1) A spot on the sheet can be left blank or printed with some sort of filler pattern. These are meant to be discarded at the printers, but a few make it through QA and become neat collectors' items.
2) A common or uncommon can be duplicated in the extra spot. This makes the card more common than others of its rarity. For example, Aether Revolt has 60 uncommons. 2x60 = 120, so I would guess there is at least one uncommon that gets printed a third time on the sheet and is more common than the others.
3) Multiple configurations of a sheet of a certain rarity can be produced so that over the course of several sheets, the numbers of each card are approximately balanced. Aether Revolt has 70 commons, so I would guess there are several different common sheets with 1 of each and 2 of some.
To answer why foil uncommons are relatively more common than non-foils, it's just a matter of them printing a higher ratio of foil uncommon sheets to foil common sheets.
Foil odds are printed on the back of each pack. The stated odds of a foil for Aether Revolt are ~ 1:67 cards. Odds of a masterpiece are ~ 1:2,160.
Do you know of anywhere that lists the pack odds for each set? I tried a Google Image search for various terms but couldn't find anything that actually showed the pack odds.
From what I can gather, this is what the normal probability should be (for a pack of a non-Innistrad-related standard set):
Many places list the likelihood of a Mythic in the rare slot being 1 in 8. However, when you looks at [url=http://boardgames.stackexchange.com/questions/12149/what-chance-do-i-have-of-my-foil-being-a-rare-or-mythic]an uncut sheet[/url], it looks like there are 2 copies of a rare for each Mythic for foils at least. This ends up being close to 1/8, but not exactly.
e.g. Kaladesh
Sheet would have 53 * 2 + 15 = 121 cards (matching an 11 x 11 sheet), making the odds of a mythic 15/121, or 12.4% (slightly less than 1 in 8). For a set like Aether Revolt, this would be 42 * 2 + 12 = 96 (which doesn't make a nice square number for sheets), with the odds being 12/96, or exactly 1/8 like the assumption.
What's even more complex is foil frequency. The most specific information I can find is [url=http://www.mtgsalvation.com/forums/magic-fundamentals/magic-general/325533-how-do-booster-pack-foils-work?comment=6]this post[/url] which gives the following odds:
It also gives odds as follows for each foil card:
This runs in to the same assumption about mythics being 1/8 of the rares. It also is old, and there are many posts here and there saying that foils used to be 1/4 packs (close to the 15/63 listed in the linked post), but are now closer to 1/6 packs. Take [url=https://www.mtggoldfish.com/articles/the-expected-value-of-kaladesh]Seth, probably better known as SaffronOlive's KLD EV article[/url] (math is number of foils per box):
This comes out to 6.125 foils/36 packs, or the 1/6 assumption out there. However, the odds of a common end up being only half that of an uncommon -- what makes the foil uncommons so much more common than their non-foil counterparts?
Looking at the numbers of cards in the set (including basics) for KLD, it looks like the foil list for non-rare/mythics is:
But again, this doesn't work so well with AER:
(Maybe this is related to the lack of a basic land slot in smaller sets? I wouldn't think that would change the size of a foil sheet though...)
If it is some combination of commons + uncommons + basic lands all tossed on a single sheet, then we'd end up with about equal number of foil uncommons to foil commons (since there are usually a similar number). This would seem to not match up well with what Seth is saying for distribution. On the other hand, it looks like Seth's distribution comes from [url=http://www.starcitygames.com/magic/misc/17092-Insider-Trading-Fifteen-Fun-Facts-About-Foils.html]a defunct website called Crystal Keep from 2009 or earlier] since it's used in an SCG article from that time saying the same thing:
For reference, Conflux's distribution was:
So that would seem to suggest that it is commons + uncommons on a single sheet, since that would make the odds 2:3 uncommon:common, which is the same as 1/18 vs. 1/12. To broaden that out to include the rares as well we'd get:
If it's a sheet with commons/uncommons, and a sheet with rares/mythics, that would make:
This seems to make sense with the odds, so there were (for Conflux at least) probably 4 common/uncommon sheets per rare/mythic sheet.
So if I were to put this together to give an answer to how to most accurately calculate EV for a set, it would be:
However, I'm a certified moron and almost positive I'm missing something/not doing this right. Does anyone have an authoritative answer on how current sets are distributed in terms of calculating the EV, including foil rarity?
First of all, sheets don't have to be square. I believe that the width is constant at 11 cards due to the machinery involved in printing and cutting. The length used to be 10 cards (which is why many old large sets had 110 of each rarity). As far as I'm aware, sheets are currently 11 cards long, which as you've seen, fits 15 mythics and and 106 rares (2 each of 53) per sheet. However, I am not certain of this.
Commons, uncommons, and basic lands are all printed on separate sheets. Flip card sheets are the exceptions. Shadows Over Innistrad likely mixed commons and uncommons on the same sheet, and original Innistrad likely mixed all rarities on the same sheet.
To handle numbers that don't fit in even multiples on a sheet, several techniques can be used:
1) A spot on the sheet can be left blank or printed with some sort of filler pattern. These are meant to be discarded at the printers, but a few make it through QA and become neat collectors' items.
2) A common or uncommon can be duplicated in the extra spot. This makes the card more common than others of its rarity. For example, Aether Revolt has 60 uncommons. 2x60 = 120, so I would guess there is at least one uncommon that gets printed a third time on the sheet and is more common than the others.
3) Multiple configurations of a sheet of a certain rarity can be produced so that over the course of several sheets, the numbers of each card are approximately balanced. Aether Revolt has 70 commons, so I would guess there are several different common sheets with 1 of each and 2 of some.
To answer why foil uncommons are relatively more common than non-foils, it's just a matter of them printing a higher ratio of foil uncommon sheets to foil common sheets.
Foil odds are printed on the back of each pack. The stated odds of a foil for Aether Revolt are ~ 1:67 cards. Odds of a masterpiece are ~ 1:2,160.
http://mtgsalvation.gamepedia.com/Aether_Revolt