JOU: Expected numbers of copies of a card

In BNG/THS/THS, an 8-person draft had an average of 1.3 copies of a given Born of the Gods common, 0.4 copies of an uncommon, 0.2 copies of a rare, and 0.1 copies of a mythic. Similarly, it had 1.6 copies of a given Theros common, 0.8 copies of an uncommon, 0.26 copies of a rare, and 0.13 copies of a mythic. While there were twice as many packs of Theros as of Born of the Gods, there weren’t just twice as many copies of a card at a given rarity because small sets have a different rarity distribution (60 commons, 60 uncommons, 35 rares, and 10 rares).

JOU/BNG/THS draft has half as many packs of Theros, so there is now half as much a chance of seeing a given Theros card at any rarity. Journey into Nyx has the same rarity distribution as Born of the Gods, so there is an identical chance of seeing a given card from either set, regardless of rarity. Here are the expected numbers for a given card from each set at a particular rarity for an 8-person draft:

So a JOU/BNG/THS draft will, on average, have the same number of any given JOU, BNG, or THS uncommon, but will actually have significantly more of any given common, rare, or mythic from either small set as it will of a THS card at the same rarity.

If a given Theros common has a very close analog in both Born of the Gods and Journey into Nyx, you’ll now have access to 3.4 copies of the card instead of the 2.9 copies you would have had in a BNG/THS/THS draft. If only Born of the Gods had a close analog, you’ll now have access to 2.1 copies instead of 2.9. And if only Journey into Nyx had a close analog, you’ll now have access to 2.1 copies instead of 1.6. Similaly, if Journey into Nyx has a close analog of a Born of the Gods card, you’ll now have access to 2.6 copies of it instead of 1.3 copies. We’ll use this information in future posts to determine the impact of the new set on existing archetypes.