the numbers on dual specs

These are the correct figures on dual spec adoption. The mistake in the original post was mine (those left outer joins will get you every time) and not a fault of the armoury. The sample size is small, so the sampling error may be large, but the general pattern  is clear enough from these numbers.

Sample size: 30K level 80s who have been played since 3.1. Choices below 2% are not shown.

Class	Specs	Popularity
Death Knight	Frost and Unholy	10%
Death Knight	Blood and Frost	8%
Death Knight	Blood and Unholy	7%
Death Knight	Two of Frost	3%
Death Knight	Two of Unholy	3%
Death Knight	One Unholy	28%
Death Knight	One Blood	21%
Death Knight	One Frost	17%
Druid	Balance and Restoration	23%
Druid	Feral Combat and Restoration	18%
Druid	Balance and Feral Combat	5%
Druid	Two of Feral Combat	7%
Druid	One Restoration	16%
Druid	One Feral Combat	14%
Druid	One Balance	13%
Hunter	Beast Mastery and Survival	10%
Hunter	Marksmanship and Survival	7%
Hunter	Beast Mastery and Marksmanship	3%
Hunter	Two of Survival	5%
Hunter	One Survival	42%
Hunter	One Beast Mastery	21%
Hunter	One Marksmanship	12%
Mage	Arcane and Fire	11%
Mage	Fire and Frost	11%
Mage	Arcane and Frost	8%
Mage	Two of Fire	3%
Mage	One Fire	29%
Mage	One Arcane	22%
Mage	One Frost	15%
Paladin	Holy and Retribution	19%
Paladin	Protection and Retribution	16%
Paladin	Holy and Protection	11%
Paladin	One Retribution	21%
Paladin	One Holy	16%
Paladin	One Protection	13%
Priest	Holy and Shadow	26%
Priest	Discipline and Holy	12%
Priest	Discipline and Shadow	11%
Priest	One Holy	22%
Priest	One Shadow	16%
Priest	One Discipline	8%
Rogue	Assassination and Combat	15%
Rogue	Combat and Subtlety	5%
Rogue	Two of Assassination	9%
Rogue	One Combat	32%
Rogue	One Assassination	28%
Rogue	One Subtlety	7%
Shaman	Elemental and Restoration	28%
Shaman	Enhancement and Restoration	18%
Shaman	Elemental and Enhancement	4%
Shaman	Two of Restoration	3%
Shaman	One Elemental	15%
Shaman	One Enhancement	15%
Shaman	One Restoration	15%
Warlock	Affliction and Demonology	12%
Warlock	Affliction and Destruction	8%
Warlock	Demonology and Destruction	8%
Warlock	Two of Demonology	3%
Warlock	One Demonology	26%
Warlock	One Affliction	22%
Warlock	One Destruction	16%
Warrior	Arms and Protection	18%
Warrior	Fury and Protection	16%
Warrior	Arms and Fury	6%
Warrior	Two of Arms	3%
Warrior	One Protection	25%
Warrior	One Fury	15%
Warrior	One Arms	14%

Oddly enough, my conclusions are exactly the same as last time despite the different numbers:

• Take-up of dual specs is much lower than I was expecting. I published figures a while back which showed that 30% of level 80s did all three of PvE raiding, BG PvPing and Arena PvPing and the vast majority of level 80s did at least some mixture of PvE and PvP. I would have thought that anybody who did PvE and PvP would want two specs – which basically means everybody.
  Perhaps people are waiting for the talent-resetting patches to stop. Perhaps the need to lay down the one large (in the Tony Soprano sense) is holding people back. Or maybe it is just too early to see where this feature is going to take us.
• The most enthusiastic adopters of dual specs are players who want a DPS-and-support combination, where “support” means tanking or healing. Nothing surprising there. Take-up amongst the pure DPS classes is lower on the whole. So only 25% of hunters have a dual spec but 50% of druids do.
• One limitation of my data is that I can’t yet sort the actual builds into raid and PvP builds. If I could do that, the picture we see here might be a bit different. An interesting question is what pure DPS classes are doing with dual specs. There seems to be two alternatives: a) having the off-spec as a spec-in-test and b) having a PvE and PvP DPS spec. So when we see that a warlock has two demonology builds, that could just mean that they are testing the second build or that they are trying to run as demonology in two different areas of the game. I’m still working on a solution to identifying builds by their intended role so I can get an answer to this question.