In some of my previous blog posts like comparing T4 and T5 for bears I make heavy use of Emmerald's %26quot;tank points%26quot;. Several readers (Kalon, among others) have asked questions about what tank points are or whether they are meaningful. So I'm going to take a step back and talk about how I use them.
Bears have a lot of options for gear. For survivability we care about three things; being crit immune, avoiding damage entirely via dodge/miss, and soaking damage via armor/health. Compared to warriors and paladins bear math is pretty simple, but it's still a lot of factors to trade off when chosing gear and enchants. Is agility better than armor? Do you want +10 stamina or do you want +15 dodge? Hard things to figure out quickly.
Emmerald's tank points is a methodology for boiling down all the stats on your gear into a single number. With this gross simplification you can then simply rank gear in a list and know which item is better than the other. The Necklace of the Juggernaut is 333.9 tank points, the Brooch of Deftness is 206.7 tank points, so the former is better for survivability. EZ-mode gear building for your bear? Choose all your items and gems to maximize your tank points. Done.
Of course it's not that simple. Foremost: you have to be crit immune, and in the high gear lists the value of crit immunity is ignored. So really to build a good survival suit you need to do two things: maximize your tank points subject to the constraint of getting 2.6% crit immunity from resilence or defense. Emmerald's high gear lists don't help you with the crit immunity, so you're on your own there.
If you optimize your gear for crit + tank points you're building the highest survival suit you can. But in addition to staying alive, tanks need to make things angry. And tank points don't speak to generating threat. I tank with the Brooch of Deftness even though it has fewer tank points because I like all the +hit and +expertise for building predictable threat. Emmerald's lists have a second column %26quot;DPS points%26quot; that give some help in calculating threat value, but I find I often have to use my judgement.
The method behind the tank points calculation isn't mysterious; it's a simple linear combination of values. Ie: in the high gear lists +1 agility is worth 6.6 points, +1 stamina is worth 4.3 points, +1 armor is worth 0.59 points, etc. Where do those weights come from? That part is a mystery. All Emmerald says is
Mitigation values use the in-game formulas for calculation of mitigation and avoidance.
Note that Emmerald's calculations are relative to a nominal value of stats. The high gear model I use assumes you're crit immune, have 45% dodge, 33k armor, and 19k health. That's a bit optimistic even at Tier 5 level, and pre-T5 bears should be using the base model which puts less emphasis on dodge and more on armor and hit points.
You can get yourself in trouble slavishly optimizing tank points. It's possible at the T5 level to build up a suit that has 45%+ dodge but under 13k health and 73% armor. That's too much avoidance and not enough soaking; the damage you take is going to be spiky and there's a chance a healer won't heal you fast enough. So use some of your own common sense in balancing your gear.
All those caveats aside, tank points are a pretty useful tool for quickly comparing gear choices. I've found it particularly helpful in figuring out where to add defense, for instance. Ie: a tank point calculation made me realize it's a lot better to use the wrist enchant for defense than gems. You'll see me referring to the tank points frequently as a useful shorthand for gear value. Useful, as long as you keep the limitations in mind.
PS: Emmerald also posts lists of cat gear, but I don't trust those nearly as much. For kitty points I prefer Toskk's feral DPS gear methodology. More on that in another post.