There are three areas which are affected by Critical Rating. There is the base 50% additional healing which results from a critical and then there is then one talent for each of the healing schools which is crit based. These are Divine Aegis for Discipline and Surge of Light for Holy.
- Flash Heal is being spammed (1887 base heal, 80.86% co-efficient. 1.5s cast time)
- Discipline has 1950 spell power
- Holy has 2147 spell power
- 45.91 Crit Rating equals 1% Crit
- 167 Intellect equals 1% Crit – Due to Disciplines Mental Agility talent they only require 145 Intellect per 1% Crit
- 30% over-heal
- Divine Aegis is 70% consumed.
- Surge of Light procs are 70% consumed
- Inspiration prevents 5% damage (for 25% armour buff) and has a 40% uptime
Base Critical value
Healing spells that critically hit heal the target for 150% of their normal healing value. To calculate the value of this additional healing we assume that the caster is using Flash Heal and use the attributes associated with that spell. To determine its value as MP5 we equate the total heal for the FH as MP5 based on the SP to MP5 ratio (0.6) and then calculate how much is additional healing is due to the critical. Over-healing is also taken into account.
Flash Heal Crit MP5 value = (base heal + (SP * SP co-efficient)) * SP MP5 value * proportion from crit * (1 – over-heal %)
FH Crit MP5 value (Disc) = (1887+(1950*80.86%))*0.6*0.5*(1-0.3)
FH Crit MP5 value (Disc) = 726.65
FH Crit MP% value (Holy) = 760.01 (Holy FH crits are bigger)
1% FH Crit MP5 value (Disc) = 7.2665
1% FH Crit MP5 value (Holy) = 7.6001
These numbers are now converted to Critical Rating and Intellect values:
- Crit rating MP5 = 7.2665/45.91 = 0.1583
- Intellect MP5 = 7.2665/145 = 0.0500
- Crit rating MP5 = 7.6001/45.91 = 0.1655
- Intellect MP5 = 7.6001/167 = 0.0455
Discipline priests have an additional effect that triggers on healing critical hits. Divine Aegis creates an additional 30% of the critical heal value as a damage absorption bubble. To calculate its MP5 value we need to once again assume Flash Heal is being cast and then calculate the MP5 value of the Flash Heal and the associated Divine Aegis.
Divine Aegis FH MP5 value = (base heal + (SP * SP co-efficient)) * SP MP5 value * 1.5 * DA bonus * DA consumption rate
Divine Aegis FH MP5 value = (1887 + (1950 * 80.86%)) * 0.6 * 1.5 * 0.3 * 0.7
Divine Aegis FH MP5 value = 653.9891
1% DA FH MP5 value = 6.5399
Divine Aegis Crit Rating MP5 value = 6.5399/45.91 = 0.1425
Divine Aegis Intellect MP5 value = 6.5399/145 = 0.0450
Surge of Light
Holy also have a critical based talent which creates MP5 value. Surge of Light provides free Flash Heals, 50% of the time, following a spell critical.
SoL MP5 per 1% crit = Spell mana cost / cast speed * 5 * proc rate * consumption rate / 100
SoL MP5 per 1% crit = 621/1.5*5*50%*70%/100
SoL MP5 per 1% crit = 7.245
SoL Crit Rating MP5 value = 7.245/45.91 = 0.1578
SoL Intellect MP5 value = 7.245/167 = 0.0434
The 25% armour buff from Inspiration grats about 5% damage reduction. Using numbers for Patchwerk 25 for a priest with 22.72% critical rating there is about 40% uptime. This equates to 0.09% damage reduction per 1% crit.
Over the course of a 6 minute fight the one of the tanks takes approximately 1,000,000 points of damage.
Damage prevented = damage reduction % x damage actually received.
Damage prevented = 0.09% x 1,000,000
Damage prevented = 880.281 (per 1% crit)
Next we calculate the number of Flash Healing spells saved by the damage reduction (including the 30% overheal).
FH healing = (base heal +(SP*SP co-efficient)) * (1 – overheal %)
FH healing (Disc) = 2523
FH healing (Holy) = 3122.7 ( I realise i’ve missed some of the the Holy talents which increase this number. They will slightly decrease the MP5 value, but not significantly)
Number of Flash Heals saved by Inspiration = Damage prevent / FH healing
FH saved (Disc) = 0.3488
FH saved (Holy) = 0.2819
Flash Heal Mana cost (Disc) = 528
Flash Heal Mana cost (Holy) = 621
Inspiration MP5 (per 1% crit) = FH saved x FH healing / Fight time * 5
Inspiration MP5 (Disc) = 2.5581
Inspiration MP5 (Holy) = 2.4314
Inspiration Crit Rating MP5 value (Disc) = 2.5581/45.91 = 0.0557
Inspiration Intellect Rating MP5 value (Disc) = 2.5581/145 = 0.0176
Inspiration Crit Rating MP5 value (Holy) = 2.4314/45.91 = 0.0530
Inspiration Intellect Rating MP5 value (Holy) =2.4314/167 = 0.0146
Next bringing it all together.