# Faction's Effective Health Math

• 06-01-2007, 02:00 PM
Faction
I looked at these numbers, and started thinking about a way to establish a relationship between the avoidance/mitigation numbers needed to sucessfully tank a boss.

Lets take a look at the Illmare's Effective HP formula with regards to Mitigation.

Code:

`LPH(Mitigation) = 1 / (1 - Mitigation)`
If we extend this same formula to avoidance.

Code:

`LPH(Avoidance) = 1 / (1 - Avoidance)`
So Effective HP

Code:

`EffectiveHP(Total) = LPH(Mitigation) * LPH(Avoidance) * Stamina * 10`
Now from posts above and many other posts from Cider, it seems that a tank should be atleast at 40% of his max HP after taking a single hit from the boss. So we can say

Code:

`BossDamage <= 0.6 * EffectiveHP(Total)`
In my experience from playing both as a Tank and a healer (Healing more so) I would say that 1.5 seconds is the minimum reaction time needed to prevent an instagib on the MT. So the Boss damage coming in 1.5 seconds should be less than or equal to 60% of the tanks effective health, which basically means that 1.5 seconds is the effective boss attack speed for our calculations. Boss damage can be calculated as

Code:

`BossDamage = (1.5 * UnMitigatedBossDamagePerHit ) / EffectiveBossAttackSpeedInSeconds`
Also, if we assume that Inspiration will be active throughout the fight, so the Mitigation equation becomes.

Code:

```                          Armor + Armor * .25 Mitigation (70) =  -------------------------------                       (Armor + Armor * .25) + 10557.5                             Armor + Armor * .25 Mitigation (73) =  -------------------------------                         (Armor + Armor * .25) + 11960```
I have not given this much thought yet. I was just playing with some numbers on an excel sheet. I know this is a very very crude model as factors like crushing blows, tank rotations etc, are not taken into account. Also, I am not sure if avoidance should be taken into account the same way as Mitigation is. Maybe using just LPH(Mitigation) for calculating EffectiveHP(Total) would be more accurate? What do you think Cider?

PS : Loving the new look of the Website! It rocks!
• 06-01-2007, 04:29 PM
Ciderhelm
I made this a separate thread so more people could check it and expand on it.

This looks very solid. I'm not good enough with math to expand on it myself, but certainly it's well done. As long as the minimum health/mitigation is met, adding in the avoidance seems logical and well done. :)

Thanks on the website comment!