Stat Choices for Discipline Priests

Stat choices for discipline priests in Cataclysm have not been easy. Especially since the changes brought on us with 4.0.6 have we seen the priest community divide with loads of priests screaming "mastery!", "crit!" or "haste!". But one has to be best, right? Not necessarily. The reason for this schism among priests right now is that no stat is beneficial to all our spells, all stats scale and synergize with eachother and in the end it will come down to which way you prefer to heal. Seriously. Even EJ will tell you to "Keep a balance to your other secondary stats. None of them are great, but they synergistically increase each other's values." The first choice is easy -  as long as you have mana issues, spirit is your best secondary stat. Once mana becomes less of a problem however, we can start looking at our other secondary stats - Mastery, haste and Crit. This post will aim at taking you through these three secondary stats, and discuss how they work and hopefully help you decide which one you prefer. I can't and won't tell you that one is better than the other because this will come down to personal preferences. I will try to explain why I have chosen the way I have, and why you should go my way, and why you shouldn't.

Not just what, but how.
Choosing a secondary stat won't just be a matter of choosing the stat based on what it does, but also how well it does it, both in term of function and in term of value. All three stats can be evaluated based on function and values. Remember how Armor Piercing worked in Wrath? It removed a percentage of the targets armor (ie made you hit as if the targets armor was of lower value). Armor Piercing was one of the most valuable secondary stats for most melee dpsers back in Wrath, but only once you reached a certain amount. In cataclysm, many argue the same way about haste. Although each point of haste is theoretically worth as much, in practice there are certain values that will benefit you more than others because of what they practically do to your spells. We can probably agree that what we want to achieve is being able to "heal as much as possible". This definition does include mana management since a healer without mana won't be healing very much. Because of this we have to look at what our secondary stat do, how well they do it, and what spells will be affected. Cataclysm introduced Mastery, somewhat as the black sheep. Unlike the mastery for holy, the discipline mastery won't affect all of our spells. In fact all of our secondary stats affect our skills very differently, and this is where our choice has to be made. What skills do I want to buff?

Mastery
I've played mainly with mastery up until now, for a simple reason. When I started out healing in Cata I played mainly as holy, because discipline was still dragging on alot of issues and just weren't performing as well. Mastery proved to be a great way to boost healing throughput without penalizing mana management, which is something haste will do. This is true for both holy and discipline, but to various degrees. To holy, most spells, and especially the most used spells, are affected by mastery. For discipline this is not so. Discipline mastery will only affect our absorbs, which means our Shields and our Divine Aegis procs. Before 4.0.6 when Shields were still relatively weak and PoH (one of our most used spells) couldn't proc critted DA, mastery was a fairly weak stat for discipline. The buff to shields has buffed our mastery as well, so it has definitely become alot better.
You need 179.28 mastery rating for 1 Mastery.

Pros

• Buffs some our most important spells (Shields and Divine Aegis)
• The only stat that provides pure healing throughput without drawback

Cons

• Doesn't affect half of our healing (Penance, Heal, PoM, PoH to mention a few) except in a secondary way, ie critted heal = DA which is affected by mastery.

Synergies

• Haste: More haste will make for faster casting which will provide more Shield and DA uptime.
• Crit: More crits equal more DA procs

Haste
Although priests are far from any agreement in this matter, it seems like most are leaning towards haste being the best throughput stat for discipline at the moment. This does rely on one factor being completely covered however - that of mana management. Haste is more healing, simply put, but the more spells you cast the more mana you will make rid of. Unlike Mastery, Haste won't improve the spells you cast, it will only allow you to cast more of them. Simplified you are choosing between throwing a few, bigger spells vs alot of smaller spells. In early Cataclysm, the choice seemed clear. Triage healing was the way to go, simply because we had to. Our mana didn't allow for us to Gatling Gun our spells like in Wrath, and haste became a secondary stat most priests didn't dare to look at (holy priests thought about getting that extra tick on their renew, and that was about it). But the better our gear gets, the better haste gets. Our spells become bigger thanks to more spellpowers which means we don't have to "patch" them up with stats like Mastery if we don't want to. With more regen comes the possibility to throw more spells, and this is what discipline (and holy) priests have been starting to return to. But what if our spells already are instant? It is true that alot of Discipline healing is based on instant cast spells - Shields and PoM. For these spells, haste will only affect the gcd which is 1,5 seconds for most spells. More haste will lower the gcd to a maximum of 1 second, allowing for more Shields to be cast within the same time frame. Also, by lowering the cast time of your Heal/GH/BH you will be able to faster recast Shields on the same target with the SoS talent.
 Haste is a rather good rating if you are one of those Atonement priests. If you like to smite your way through stuff, which I personally think works ok for heroics but not so well for raids, you won't have any gain from Mastery (except for the occasional DA you proc) but plenty of gain from Haste and Crit. More Haste will allow you to stack Evangelism faster, which for many priests is the main goal of smiting overall.
You need 128.125 haste rating for 1% Haste.

Pros

• Increased healing throughput
• Effects all spells
• Is the "cheapest" rating.

Cons

• Only efficient if you have the mana and regen for it

Synergies

• Mastery: Haste has no gain of Mastery
• Crit: Haste has no gain of Crit

Crit
Crit is tricky. It does affect some important spells, like Inspiration and Divine Aegis, and critting a heal isn't a bad thing to do. On the other hand, crit is the most rng of the three secondary stats. Having a certain amount of crit won't benefit all of your skills and most importantly it won't affect them all the time. It will only benefit your overall healing to a certain degree (approximately the amount of crit you have). Does this mean that 15% crit will increase your healing effectiviness by 15%? Not at all. You can't count on your crit throughput unless you have a very high amount of crit (which we won't get without sacrificing too much of our other stats). Theoretically, all the crits you get during a certain time frame could be overheals or otherwise non-beneficial for the situation. Unless we have a really high amount of crit, we won't heal as if our spells will crit. This means you will keep on casting your spells with their non-crit value in mind, easily making alot of the crits overheals. It is only when your spells are insufficient that crits are welcome. Healers tend to avoid getting into situations where we have to rely on luck to get the job done.
Like mentioned, Crit is a fairly good stat if you use Atonement. Smite healing is effective in that it has a high hps without being very mana expensive (unlike other fast spells like Flash Heal), and with alot of crit you can proc loads of DA from all that smiting.
You need 179.34 crit rating for 1% Crit.

Pros

• Is our only source of DA (except Prayer of Healing)
• Is our only source of Inspiration (if you have that talent)

Cons

• Doesn't affect our Shields at all
• Is the most unreliable of all secondary stats

Synergies

• Mastery: Crit has no gain of Mastery
• Haste: More haste equals more spells equals more crits (during a time frame).

So what secondary stat is the best?
Because of the unreliability of crit, and the fact that it doesn't actually affect a spell that makes out some third of my total healing done (note that I write "my" here) I have chosen to mainly focus on haste vs mastery. That doesn't mean that there aren't priests out there who have focused on crit and do a great job anyway (link in german), which just emphasizes the difficulty in saying that one secondary stat is better than another. Ideally we'd put all our eggs in the hps basket, meaning we'd convert spirit (which is useless as long as you have enough mana and regen) to Mastery and Haste (and crit if you like that). To most of us it is still a tough choice to remove spirit meaning we have to choose between the throughput stats and not between regen vs throughput stats. However it is worth noting that if you feel like mana isn't much of a problem for you, converting spirit into the other secondary stats is the best idea, and this is also something currently being discussed around the bloggosphere. Like I started out saying, what secondary stat you should choose for yourself comes down to your way of healing. A thumbrule is that haste is good for raid healing, because of faster PoH, Mastery and Crit is better for tank healing. I'm in a position where I switch between the roles, so I will have to balance the stats. This is a situation I think most discipline priests are in actually.

To try to find out if there was a big difference between lots of haste or lots of mastery (I did not check crit) I decided to reforge my gear completely. From being all Mastery to all Haste, I also switched some gear from Mastery gear to Haste gear.
I lost 2 points of Mastery, from ~18,5 points Mastery to ~16,5 (or 5% absorbtion).
I gained about 5,5% haste, from 5% to 10,5% (unbuffed).

Here are some comparison logs between two raids. I've picked out the fights that were the most alike between the two raids in terms of my spec and role in the fights. The raid compositons were about the same, I used the same flasks and food, but note that there are still differences between the fights of course.

The fight healed with Haste is to the left and the fight healed with Mastery is to the right.

Magmaw - 1000 more hps with Mastery than Haste.

Omnotron - 2000 more hps with Mastery than Haste

Cho'Gall - 400 more hps with Haste than Mastery

Let's take a look at healing values.

Magmaw

Omnotron

Cho'gall

Interestingly enough, my average absorb with shields actually rises on two fights with more Haste, rather than with more Mastery. Divine Aegis on the other hand drops in absorbs. These logs are from two raids only one week apart, so I couldn't ascribe that difference to gear, neither was there a big difference in raid setup as mentioned. Statistically there isn't much to get from these numbers of course, because it's just one raid of each, but it does highlight the point that whether you choose Haste or Mastery (and maybe even Crit) as your primary stat, things won't change dramatically. When people tell you to keep a good balance, they are right. I don't post these logs to give you proof of one way or the other, but to give you a general idea about what these differences could do, or rather don't do (and encourage you to experiment a little with stats yourself).

How did the change feel? I did feel like mana was slightly more of an issue, but I will ascribe that to the fact that we had one less Mana Tide for the Haste-raid than for the Mastery-raid. Regarding comfiness I really liked having faster spells. With the haste I had the cast time on Heal/GH went down to near 2 seconds and with PI/BL I got down to 1,5 sec cast. My overall performance didn't change much though, it seemed like my hps went down a little with more haste which could be because the strength of Discipline really lies in Shields at the moment and it is difficult to compensate that with more PoH (which is mainly why you'd want alot of haste). In my case we already have a bunch of good aoe healers, and boosting my own aoe-healing will get me higher on the meters, but will it benefit the raid? Being able to keep up strong single-target healing is just as important although it doesn't look as cool on the meters. We have to evaluate our own role in our raids and gear suited to that role.

Where will I go from here? What do I recommend? Depending on your current gear I do recommend getting a fair amount of haste, maybe some 15-20% raid buffed (which isn't too hard to get) and then go for Mastery. I wouldn't recommend going for Crit, because I feel like the other two stats are outperforming it, but I won't tell you crit is bad either. Crit on gear isn't something to avoid, but I wouldn't gem/enchant/reforge for it if there are options to go for Haste or Mastery instead, simply because they are safe throughput stats and Crit isn't. For single-target healing (and multi single-target healing) I don't have any problems with keeping Inspiration up on my targets even when not gearing for crit.
As boring as it sounds, a balance does seem to be the best idea, and testing with different values for yourself will probably be the best way to find out what suits your healing style. Because the stats affect different parts of your healing, it does depend on your healing role and the fight you are fighting to find the best stat for you.