Holy Paladins: +Healing vs. Spell Crit vs. Mp5

More boredom at work has had me producing another spreadsheet for calculations. I wanted to see the equivalency of all of the different stats to get a better idea of their weight.

Note: This may have all been figured out somewhere else, possibly at elitistjerks. I can’t read from their website at work, and thus when I am curious about it I get to do it all myself. :(

My main concern was figuring out Spell Crit. For Holy Paladins, Spell Crit has the simoultaneous function of providing both the potential for increasing healing done and mana regeneration. But how does it weigh in against the stats that purely do just those two things?

[/edit: A brief explanation: Achieving a critical heal will increase the healing done by that spell by 50%. This will, over time, bring up your average healing done, and converting the amount by which it does into +healing was my objective here. The mana regeneration component is part of the talent Illumination, which refunds 60% of the mana cost of the spell when it crits. This could be averaged out to be an equivalent of mp5.]

Interestingly enough, I’ve found, it depends on which spell you’re casting.

Comparing spell crit to +healing is fairly complicated, as the benefit you get from spell crit varies based on how much +healing you have, so it’s difficult to do a direct comparison…however, it could mean that at a certain level of +healing, spell crit will do more for you, especially when you factor in the mana regen potential. It could be like reaching a hit cap…but I haven’t figured that out yet.

[/edit: Ok, here it is. For Holy Light, 1 spell crit rating equals 1 +healing at approximately 1151 +healing. In other words, at 1151 +healing, adding on 1 points of spell crit rating will generate the same effect over time as 1 point of +healing. For Flash of Light, well...it's the pretty lofty goal of about 3292 +healing for 1 spell crit rating to equal the benefit of 1 +healing.As far as item budget points go, with 8 spell crit rating being "equal" to about 18 +healing, it gets considerably worse. For one "unit" of spell crit rating to catch up to one of healing, it requires 6000-some +healing...a relatively unattainable number, if I do say so myself. And that's just for Holy Light! To match the numbers with Flash of Light, you need 8800+!]

Basically, every 100 +healing makes every 1% spell crit equal to another 0.5 +healing, plus a base number.

A simple formula:

(H/200 + X) * C

H is your +healing. C is your holy spell crit chance (multiplied by 100 so it is no longer a decimal). X is one of two different numbers…5.54 for Flash of Light, and 16.25 for Holy Light.

For example, if you have 600 +healing and 5% crit chance, casting Flash of Light:

(600/200 + 5.54) * 5 = (3 + 5.54) * 5 = 8.84 * 5 = 44.2

Thus, your 5% crit chance is worth 44.2 +healing for Flash of Light.

If you have 600 +healing and 30% crit chance (unrealistic I know, but for comparison’s sake):

(600/200 + 5.54) * 30 = 8.84 * 30 = 265.2 +healing equivalency

For Holy Light, change the 5.54 to 16.25. Both of these numbers are approximations (rounded values), and are based on the increase in healing you get at 1% spell crit with 0 +healing.

For example, casting Holy Light with 2000 +healing and 30% crit chance:

(600/200 + 16.25) * 30 = 577.5

So, clearly, spell crit has a greater benefit when casting Holy Light (577.5 as opposed to 265.2, with equal amounts of spell crit and +healing).

Edit: If you have 3/3 Healing Light, the numbers change to 6.2 for FoL and 18.2for HL. Again these are approximations (the actual numbers are more like 6.20667 and 18.19664).

As far as mp5 is concerned, since the costs of both spells are (for the most part…you know, barring the use of trinkets/librams) static, the formula is much simpler for comparing it with spell crit.

[/edit: Spell Crit equating to Mp5 is not ideal as you will not regen mana through spell crit if you are not casting (because you're out of mana, silenced, etc). It is perhaps better to look at Spell Crit as an increase to your overall mana pool, detailed here.]

To more easily figure things out, I calculated what you spend in mp5 when casting both spells. For Flash of Light, you effectively put yourself at -600 mp5. For Holy Light, -2100. In other words, if your character pane says you have 100 mp5, if you are chain casting Flash of Light, you are effectively losing 500 mana every 5 seconds. Since mp5 is a more static value and subtracts from these much different numbers, you can see that mp5 has a much greater effect on FoL than HL. 100 mp5 is a 17% reduction in the mp5 loss of FoL, while only a 5% reduction in HL.

I calculated these values with Light’s Grace active. (Reduces your Holy Light cast time by 0.5 seconds, ie, reducing it to a 2-second cast time.)

Anyway, back to spell crit…we find again that spell crit as a statistic favors Holy Light more favorably, and again, the formula for spell crit vs. mp5 is much simpler.

C * X

C is your spell crit (again, multiplied by 100), and X is 3.6 for FoL, 12.6 for HL.

If you have 5% spell crit:

Flash of Light: 5 * 3.6 = 18 mp5
Holy Light: 5 * 12.6 = 63 mp5

With the above formulas, it should be easier to calculate gear upgrades. You can convert spell crit into +healing and mp5 to more easily make a decision. (Though, your numbers won’t be as friendly…remember 22 crit rating is 1%, so you’ll need to divide your rating value by 22 in order to get the %. An add-on like Rating Buster is handy for this.)

However! What the calculations do not factor in is burst healing, a concept that I’m not sure I can quantify. The fortunate aspect of paladin healing is that, as long as the overheal was due to a spell crit, we do not “waste” as much mana since it is returned to us. However, there are times (especially when healing a recipient of Mortal Strike) when burst healing is necessary…much like burst damage. You may not be given the opportunity to chain cast, either due to line of sight or spell interruptions, and so you want your heals to hit for as much as possible when they do.

This also unfortunately does not factor in bonuses to Intellect. I can, perhaps, return to that in a different post.

Yet another problem is a component of the spell crit mana regeneration…which is that it cannot happen if you do not already have mana to cast…where as mp5 is always happening. This is important after uses of Lay on Hands, where the paladin will be reduced to zero mana.

Something else you can garner from this is itemization theorycraft. In the mp5 example, we see that 5% spell crit is equal to about 18 mp5 for Flash of Light. That is roughly 110 spell crit rating. In Blizzard’s terms, 3 mp5 is roughly equal in value to 8 spell crit (you can see this in the gem system)…if you extrapolate that, you get 6 “units” of mp5 in exchange for 13.75 of spell crit rating with Flash of Light. If you instead use Holy Light, it’s 21 units of mp5 for that same 13.75 of spell crit. It’s an interesting system of tradeoffs.

Edit: There was a math error in the mp5 formula, and the base numbers for both FoL and HL have changed. Sorry about that.