Wednesday, May 21, 2008

Spell Damage vs Spell Hit (For Moonkin)

Note: This guide was written well before WotLK as released. The information and modeling done here is based completely on a BC version of WoW. While I thing this information is still generally correct, It does not apply direct any more. I do plan on writting a new guide and will post on my blog when it is done.

This is the most accepted rule within the Moonkin community. I don’t think I have ever seen it argued. However, it isn’t uncommon to see questions on the forums regarding Spell Hit. The general rule of thumb has always been that one spell hit is equal to 1.2 spell damage and that you should maximize your spell hit as soon as possible. I don’t disagree with that but I would like to provide a little more detail to explain why.

1. Spell casts that crit can also miss, therefore Spell Hit and Spell Damage are equally affected by spell crit. So, for the purpose of this evaluation Spell Crit can be ignored.

2. Spell Haste does not impact the amount of damage caused by Spell Damage or Spell Hit. It only affects the speed at which the damage occurs. Therefore it affects both Spell Damage and Spell Hit equally and will not be included in this analysis.

3. This analysis has been written using Starfire but all moonkin spells are equally affected by Spell Hit and our available Spell Hit buffs. Therefore this analysis can be applied to Wrath and other Moonkin Spells.

4. Calculations are made assuming the caster is max level and the target is a skull level raid boss.

5. All calculations will assume that Balance of Power is maxed out.

Talents and other Buffs Affecting Spell Hit:
Balance of Power – Talent - Increases a spells chance to hit by 4%.
Inspiring Presence – Buff – 1% chance to hit. Draenei racial group buff if Driaenei is a Priest, Mage, or Shaman.
Totem of Wrath – Buff – Increased chance to hit by 3%.

General Spell Hit Info:
* A spells base chance to hit is determined by the caster’s level relative to the target’s level. A spell is less likely to hit if the target has a higher level then the caster. Conversely a spell is more likely to hit if the caster is a higher level then the target.
* A caster cannot improve his spell chance to hit above 99%.
* Skull level bosses in raids are considered to be 3 levels higher than the caster. Therefore the caster has a base chance to miss of 17%.
* One point of Spell Hit equals 0.07927% chance to hit. Put another way 12.615 spell hit equals a 1% chance to hit.

The Math:
The value of Spell Hit and Spell Damage are highly dependent on each other. The value of Spell Hit is largely determined by how much Spell Damage you have, because Spell Damage is plays a large part in how hard your spells hit. The value of Spell Damage affected by your Spell Hit because if you cast long enough, eventually as spell will miss. So we can reduce the damage caused by the miss rate to find how much your spell will hit for on average..

How much additional damage will you receive from an additional point of Spell Damage?
Moonfury, Wrath of Cenarius and your hit rate all affect Spell Damage. Starfire has a base Spell Damage Coefficient of 1, and let X equal your hit rate. So the additional damage from one point of Spell damage is:

Damage = ((1 + 0.2)*1.1)*X, So if your hit chance is 95%, Then
Damage = ((1 + 0.2)*1.1)*0.95
Damage = 1.32*0.95 = 1.254 actual damage per point of Spell Damage with a 95% hit chance.

How much additional DPS will you receive from an additional point of Spell Hit?
First we need to figure out how much damage Starfire does when it doesn’t miss. It has two components, base spell damage and bonus spell damage. Base spell damage is the damage that comes with the trainable spell with no bonus from gear. A max rank Starfire can hit for between 550 and 646. It is increased by 10% because of Moonfury, so the average base spell damage for Starfire is 657.8. Bonus spell damage is what you receive from gear and is calculated on your character screen. It is modified based upon the base casting time of the spell and talents. Starfire has a Spell Damage Coefficient of 1, and it is modified by Wrath of Cenarius and Moonfury as I said before. So the damage of your average non-miss Starfire is equal to:

Damage = 657.8 + (Spell Damage)*(1 + 0.2)*(1.1)
Damage = 657.8 + (1000)*(1 + 0.2)*(1.1) = 1977.8, If you have 1000 Spell Damage

To get the damage of your average Starfire you have to include Hit. To do that, multiply the entire equation by your hit chance:

Damage = (657.8 + (Spell Damage)*(1 + 0.2)*(1.1))*(Hit Chance)
Damage = (657.8 + (1000)*(1 + 0.2)*(1.1))*(0.95) = 1878.91, If you have 1000 Spell Damage and a 95% hit chance.

Now, if we had one point of spell hit rating to the percentage then we increase the average damage per spell cast. To increase your hit chance by 1% you need 12.615 points of hit rating. So one point of Spell Hit increases your chance to hit by 1/1261.5 or 0.07927%. If you slip this into the equation you get the following results:

Damage = ((657.8 + (Spell Damage)*(1 + 0.2)*(1.1))*(Hit Chance + 0.0007927))
Damage = ((657.8 + (1000)*(1 + 0.2)*(1.1))*(0.95 + 0.0007927)) = 1880.48, If you have 1000 Spell Damage and a 25% base crit rate plus one more point of Spell Crit.

So from one point of Spell Hit you gain 1.568 actual damage with 1000 Spell Damage and 95% base Hit rate. Lets compare this value to the actual damage value I calculated for one additional point of Spell Damage.

1.568/1.254 = 1.25

So, at 1000 Spell Damage and 95% Hit rate, one additional point of Spell Hit is worth 1.25 points of Spell Damage.

I have calculated this value for several levels of Spell Damage and Spell Hit. Here is a graph that shows the results.

1. My results do confirm the relative value of one Spell Hit to be worth about 1.2 Spell Damage for your average raiding Moonkin with about 1000 to 1100 Spell damage.

2. Moonkin should start picking up Spell Hit very early in their raiding experience since it passes Spell Damage in value at around 600 Spell Damage. Moonkin should also try and Hit cap fairly early in their raiding experience since it pays to cap at about 750 Spell Damage. Both of these values are very easy to reach with out raiding. If you include normal raid buffs 99% raiding Moonkin should be past these levels of Spell damage.

3. Even the top tier of raiders need to worry about being really close to the hit cap. At the highest levels of Spell Damage, Spell Hit is significantly better than Spell Damage. Dropping a couple of points of Spell Hit for a little Spell Damage can be risky.

Additions thoughts on Spell Hit:
1. It has been suggested by some on the forums that you can drop a point or two from Balance of Power if you are 25 to 50 points over the Hit cap. It is true that if you are 25 points over the hit cap that an additional point in Subtlety, Imp FF or some other talent will server you better. However, I recommend against ever dropping points of Balance of Power. I say this because we really don’t have any other talents that significantly increase our DPS, and it is generally very easy to drop Spell Hit and increase other stats like Spell Damage and Spell Crit. If you are in a position where you have to make this choice, my first suggestion is to change all of your Hit gems to Crit or Haste. My second suggestion is that you look for lower level gear in Kara and other raids that is better than your current item if you exclude the Spell Hit from the item you currently have equipped.

2. Try and build a set of Spell Hit items and items without Spell Hit. I suggest this for a couple of reasons. First, it makes adding new pieces of gear to your set a lot easier. If a new piece pushes you over the Hit cap then you can switch around some of your other gear to lower your hit and increase your Crit and Spell Damage. Second, having a Draenei or a Elemental Shaman in your group will increase your sell hit and probably push you over the hit cap. In such a situation being able to change out a couple of items can increase your DPS.

3. Spell Hit only helps when you are fighting a mob that is a higher level then you are. Balance of Power will bring you up to the hit cap fighting a mob that is the same level as you. Plus, you don’t need much Spell Hit to Hit cap against a mob that is only one or two levels higher then you so you don’t need that much when instancing or doing raid trash. This is why I don’t ever put pure Spell Hit gems. Spell Hit may be more valuable against a raid boss but Spell Damage will help me in every fight including PvP.

Wrath of the Lich King News:
If you troll the forums and news sites you already know about the "Leaked" Talents and such. Obviously Blizzard wants to keep this stuff secret and have pressured many of the News sites to remove it from their sites and most have done so. If you would like to look at some of the "Leaked" info you can find it here. I do want to stress that this is a Wiki site so who knows how much is real. Also this is very early Alpha phase information. It is very likely that the real info will change before the release or may not be included at all. Don't get excited about what you see until we get more concrete info. That being said I will post my reaction to this info in the near future.

Toon Update:
- Raiding as usual. We ended up not getting Vashj down this week because we didn't have a good group for it. We tryied her on Thursday and did pretty well but had trouble getting the adds down quick enough. The difference would probably have been a shadow priest. An additional 15% for our warlocks and 5% for the rest of the raid is amazing. If you are a Shadow Priest looking for a guild. Click my Guild website link and App. We need more of them badly.
On a positive note we did get Shade of Akama down for a guild first kill. That fight is a joke. It took us a couple of trys to figure out the adds but once we did he went down with a quickness.

Graypal - Nothing really to say here. I didn't run kara with him and didn't get any heroics in.

Grayfel- Did a lot with him over the weekend. Got him up to level 47 and used up most of his Rested XP. His gear is pretty sad because I haven't really run any instance with him. I could go buy some from the AH but I don't really think it is needed. Anyway, He will be 60 in a month or two and will get tons of good gear. I think I have desided that I am not going to go to outland until he is 60 this time. I am doing this for a couple of reasons. First, I want to see WPL and EPL. I didn't do much in these areas with Graylo and none with Graypal. I have seen so much of the zones I have quested in so far it will be nice to see something new. Second, I hate grinding, and I had to grind in HFP a little bit with Graypal because I went there at 58 and some of the quests were not available until I hit 60. Third, the primary reason I have leved this guy is for gems. I want to make sure my mining is up to 300 before I get to outland and I am not sure I will make that if I go there early.

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