Defences/Mitigations/Resistances

Defences, resistances and mitigations are a pretty confusing part of the game so I thought I'd put up some info on them here becuase mitigations are critcally important in ost dunhoth especially as we move into T2. We will be recommending specific equipment and virtues for different wings and I'd like to explain why some things are and aren't important.

Defences

Every single bit of damage your character takes will come from one of three sources: melee, ranged or tactical. Some attacks may have both a melee/ranged AND a tactical component. Determining what the damage source is is often quite difficult as except for some attacks which are named very obviously (eg. "a melee attack"), the combat log does not explicitly track damage source.

Defending against a source of damage that you are commonly taking will dramatically increase your survivability. Generally, it is more important to mitigate against a damage type you'll be taking a lot of than to boost other stats, even vitality/morale.

Note that warding scrolls give +1000 rating to defences against all three of these sources (which is why they're so important!).

The cap on all defences is 15%. This is attained by having, at level 65, a defence rating of 4550.

In general, most classes will benefit from some level of melee defence (including healers and squishies who might occasionally draw aggro or take AOE melee attacks). Things that boost melee defence are virtues (innocence, zeal), relics, legendary item titles and certain equipment, especially pocket items. Debuffs that reduce melee damage are fire lore (LRM, -30%) and disable (BRG, -15%).

Tactical defence can be extremely important in certain parts of raids. Tactical attacks cannot be blocked, parried or evaded so you will take the full amount of the attack without some tactical defence and these attacks are frequently random so it's important that all raid members build for tactical defence when there are lots of tactical attacks. Things that boos tactical defence are virtues (honour, mercy), relics, legendary item titles and equipment (eg. charm of defence from Mirkwood, Clinker from the Forges instance). Only one debuff reduces tactical damage, frost-lore (LRM, -20%)

Ranged defence is rarely important. In general play, most classes will take minimal if any ranged damage. If there are archers dealing ranged damage then they are usually either crowd-controlled or quickly brought into melee range by tanks. As a general rule, no one should specifically build for ranged defence. The exception to this rule is when hunters are ranged tanking physical damage mobs (eg. trees in OD disease, tentacles in the Watcher). In these situations, ranged defence is very important. Two debuffs reduces ranged damage, wind-lore (LRM, -50% or -60% traited) and distraction (Raven LRM pet, -50%).

Mitigations

In addition to a source, everything that damages you will have a damage type. Specific damage types can be mitigated against. Damage type is explicitly noted in the combat log on each attack.

The cap on common mitigation differs depending on what type of armour you can wear: Light (30%), Medium (40%), Heavy (50%). At level 65 these caps are achieved by mitigation ratings of 4178, 6500 and 9750 respectively. There is no (known) cap on non-common mitigations.

Again, mitigating against a damage source that you commonly take will greatly increase your survivability.

The most basic damage type is "common". Common damage mitigation is boosted by armour value and might. Common mitigation is: armour value + might.

There are five other damage types - Fire, Frost, Lightning, Acid, Shadow. Non-common mitigation rating is determined by the following formula: Armour/5 + Vitality + Direct bonuses.

The only damage type mitigation which can be boosted through virtues is shadow (Fidelity, Honour, Innocence). Many raid bosses do shadow damage, especially AOE shadow attacks, so these virtues can be very important.

The only other way to directly increase mitigations is with equipment. Many raid and dungeon armour sets will give mitigations to specific damage types as a set bonus (eg. moria gives acid, DN gives fire, Mirkwood gives shadow). In certain raid fights with heavy damage of a particular source, it is better to use equipment with sub-optimal stats or set bonuses with the right mitigation type.

Resistances

Resistances give you a chance to ignore wound, disease, fear or poison effects. Base fear resistance = will * x 2 and base poison/disease/wound resistance = vitality * 2. Resistances can be further boosted by fortifying food, virtues, equipment and specific skills (Captain muster courage, lore-master ancient cures and hunter purge poison).

Resistances cap at 30%. This equates to a rating of 11050 at level 65.

Unfortunately resistances aren't nearly as good as they seem. while the tooltip will say that you have a 30% chance of resisting, say, a fear with a rating of 11050 this does not actually mean that you will resist the application of a fear 30% of the time!!!. Now, how these things works isn't entirely clear but it seems that the resist rating only applies to damage "ticks" of certain types of fear/wound/disease/poisons and not to the initial application of the effect. So unless there is a relevant effect that applies a damage over time effect to you, resistances are completely useless. Resistances will not stop you getting disease eyes in OD disease wing, will not stop you getting the wound bomb or armour rends being applied to you in the OD wound wing and will not stop the balrog's 'yank' fear being applied to you in the fear wing. Basically if what you're trying to protect against is an effect you are going to have to pot or clear anyway then boosting your resistances will not help you. It's only in circumstances where there are a huge number of DoT effects being thrown around (such that you can't clear them all) that resistances will help you.

Further reading

Stats for survivability (MMORSEL)

It's funny you should post this babble, I was only thinking last night how mostly useless Resistances are.

As I'm levelling up more and more virtues, I'm looking more closely at what would be better to slot, not just for raids, but in general as well.