Diablo 3 Shield Blocking Analysis for Barbarians Guide by DreadTalon
I have been seeing a lot of people posting about how they have great block gear (Stormshield, Justice Lantern, Helm of Command) and they still get trashed in Act 3. While some other people claim block to be incredible for their characters.
In this article I will explain mathematically why this is the case and show a calculation which measures how effective block is or can be for you.
The first thing you have to understand about block is that it is a mechanic that varies in efficiency based on the enemies you are fighting. In the best case scenario, the block amount on your shield (4700 for a Sacred Shield) exceeds the damage dealt by the enemy monsters. If this is the case you take 0 damage while blocking and your incoming damage is reduced by whatever your block chance is.
I have done a bit of research into monster damage in Act 3 Inferno and compared it to the quoted values in the official strategy guide and found them to be consistent; atleast prior to 1.0.3 potential nerfs. The average melee monster such as a Blood Clan Goatman or one of those green Fallen Hounds deal approximately 200,000 damage per hit. The stronger melee monsters such as Skeleton Executioners deal around 300,000 damage per hit.
To do a quick calculation; some person who has 45% block total, 75% reduction from armor and 75% reduction from resistances will receive:
Damage = 200,000 * 0.25 (Armor Reduction) * 0.25 (Resistance Reduction) * 0.7 (Barbs and Monks recieve 30% less damage) = 8750
The average block is going to reduce your damage taken by:
Block reduction = 4200 (Average block value) * 0.45 (Block Chance) = 1890
This means that block reduces your incoming damage by about 21.6% or it increases your effective life against these enemies by 27.5%. Not all that much bang for your buck for those expensive uniques; actually storm shield has even less block amount than a sacred shield so your results with one would be even worse.
We cant really improve our shield?s block amount or block chance. The only way to make block work for us is to reduce the incoming damage to a value that our shields can deal with. Let?s look at what kind of benefits we get from 80% reduction from resistance and armor instead of 75%.
Damage = 200000 * 0.2 * 0.2 * 0.7 = 5600
Block amount is still 1890, but now the damage reduced by block has risen to 33.7% or an effective health boost of 50.8%. Almost double what we were getting before.
A couple of important things to note here is that this relationship utterly ignores your current health. The only things that affect block are your damage reduction stats, resistance and armor. So while I am a proponent of effective health when it comes to gearing; if you are interested in block it is worth keeping in mind that increasing your health pool will actually do nothing to improve the way your block operates.
The rewards that you get from the shield are exponential related to your enemy. If you have 50% effective health boost against an enemy like a Blood Clan Goatman you would recieve a 160% boost against enemies like Fallen, quite as if you had ignore pain on all the time against these enemies. On the other hand, your shield will perform exponentially worse against elites who deal more damage than their normal counterparts unfortunately.
So the conclusion here is that to get big benefits from a shield against trash monsters in act 3 you need about 10000 armor and 1000 all resistance. Just slapping on a shield will show barely any improvements unless you have the damage reduction to support it.