Itemization Formulas (WoW)  

A close look at random greens easily reveals that there is a system for how these items decide how much of each attribute they have, considering all items of the same level have numbers in the same range. As time moved on, and players wanted to know more about how Blizzard created the more specific items, it became apparent that there is an overall system for how items gain the attributes they have.

Hyzenthlei, a shaman from Zul'Jin server, did a massive analysis of items in early 2006. Hyzenthlei reasoned that Blizzard gave an item a "budget" of so many points, and that each attribute point had a certain cost toward that budget. Determining the relationships between these items, and the amount of points an item had was a complex process, but through very rigorous proof on the official WoW forums, he convinced a majority of the community of exactly how Blizzard's system works. Months later at Blizzcon, a presentation revealed the actual budget costs that Blizzard used that matched Hyzenthlei's system, except using much simpler numbers.

The Budget of an Item

Every item has its own level, called an item level or "ilevel" for short. For most low-end items this is the item's required level +5. For gear at level 60 and beyond, the item levels do not correspond well or at all with character levels. While it is not always simple to obtain an item level simply from playing the game, most websites that use a datamining utility (such as WoWreader for Allakhazam) can obtain this information.

Second, the quality of the item is factored in. Greens, blues and purples all use a slightly different formula, even though it is similiar in nature.^[1]

The final factor to consider is the slot the item is for. Generally a chest-slot item will have better stats than an item for the hands slot. Take the results of Table A and multiply it by the following:

So for example, a green level 42 (level 37 required) shoulder-slot item would have:

• An ilevel of 42
• A basic item budget value of 0.5*42 - 2 = 19
• A final item budget of 19 * 0.77 = 14.63

This means that this item would have 14.63 "points" to spend toward attributes. If this item was "of Agility" (or any other single attribute,) it would have either 14 or 15 points of agility on it.

An epic (purple) neck item with an ilevel of 112 would have (0.77*112 - 1) * 0.55 = 46.9 itemization points.

Values of Items

One noticeable quality of Blizzard's system is that it does not heavily punish hybrid players for needing multiple attributes. An item with a pure single stat does not have twice as much as an item evenly split between two attributes. Items like Songbird Blouse would have closer toward 4 or 5 of each attribute rather than 13 if this system were not in place.

Specifically, the actual cost of a particular attribute increasing with the more of it you have, on an exponential level. (To the 3/2 power, to be exact.) More on this later.

To find the cost in points of a single attribute on an item, multiply it by the following values:

There are also sometimes other qualities found on items that have to be assigned their own unique costs. For example, items that add 1 to your stealth level will have a cost of 7.

The complicated part of this process is that everything must be raised to the 3/2 power and then added together, and should equal the budget (also to the 3/2 power.) So:

Itemization Points ^3/2 = Attribute Cost #1 ^3/2 + Attribute Cost #2 ^3/2 + ...

So the epic neck from above (which had 46.9 itemization points) might have: +40 spell damage +20 intellect +28 stamina

This would work out as...

46.9^1.5 = (40*0.7)^1.5 + (20*1)^1.5 + (28*0.67)^1.5
321.19 = 148.16 + 89.44 + 80.64
321.19 (budget) = 318.24 (cost)

...which is pretty close. The Blizzard guys would try to fiddle with it to make it use those last 3 points, perhaps taking a way a few stamina to add 1 more intellect. But the neck with these stats is a plausible epic level 112 item.

Notes

1. ^ Most of the actual numeric values were taken from the article on WoWwiki, however the accuracy of these values is doubtful.
2. ^ This value was changed with Burning Crusade, and was originally 1 as well