Succeeding at giving way

A rolling mass of stone and earth is loose around the room, devouring anything, living or inanimate, in its path. Turning a corner, you breath a sigh of relief, having gained distance from the voracious being known as Oregorger. You are safe for now.

Unexpectedly, as if in an instant, the unstoppable goren zips to the intersection you just passed. Dazed by the collision against the wooden picket fence, it halts for a bit, although you know it will be mere seconds before it makes off again, almost certainly in your direction.

Run away: Turn to page 87
Try to run behind it: Turn to page 155
Turn the next corner: Turn to page 172

In the second phase of the Oregorger encounter in Blackrock Foundry, the namesake boss drops whatever it is doing and enters a Rolling Fury. At first it may seem random, but the motion observes a few very simple rules:

Yor'sahj's Law (of Deep Corruption)

Of all of the blobs of blood Yor’sahj the Unsleeping may call from Shu’ma, none are more confusing than the Shadowed Globule. Its unique buff (debuff to the raid), Deep Corruption, means that:

Receiving healing or absorption effects will trigger a detonation at 5 stacks.

So, which healing and absorption effects generate Deep Corruption? Apparently, this is a matter of law that requires some interpretation.

Summary
Abilities that generate Deep Corruption are:

• Single heals
• Heals-over-time (HoTs)
• AoE heals
• Aura AoE heals
• Ground AoE heals.

Abilities that do not generate Deep Corruption are:

• Non-heals
• Non-healer abilities
• Trinkets and the like
• Summoned totems
• Abilities with secondary effects for as far as the secondary effect(s) is/are concerned.

Non-heal rule

An ability without any healing or absorption effects does not generate Deep Corruption.

Looking for Equilibrium

When using the Dungeon Finder to find a group, damage-dealers (dps) endure long waiting times, while tanks and healers enjoy a much shorter time in the queue. Since the facility was introduced, this has remained the case.


One may wonder why the average waiting time for a dps has not decreased, but instead even increased, since then. Having economic insight, one may envision the three roles as three choices a dungeoneering player decides on as part of an economic decision, and also that the the three choices, on the large scale with several people, tend to economic equilibrium with each other.

Cost and benefit
When faced with a choice of activities to perform, a person makes an economic decision whenever they try to gain the most satisfaction by choosing the best activity for them. For each activity, they need to compare the costs incurred with the benefits gained. The excess of the benefit over the cost is their (accounting) profit from the activity:

Accounting profit = Benefits - Costs

WoW Mathematics: Steady-State Health Level

In the final phase of the Anub'arak encounter in the Trial of the Crusader (ToC), healers must heal through a variety of sources of damage, including Penetrating Cold and Leeching Swarm. While the former deals constant damage over time, the latter does more damage the higher players' health levels are! The raid might be interested in knowing the optimal health level the healer(s) can keep the players at.

At the steady-state health level, DPS of Anub'arak against the raid equals the HPS of the healers for the raid. From here, health levels do not tend to move either way; they are stable, and this determines whether the healers can provide enough healing.

Summary:

• Where h is the total HPS, r is the proportion of current health Leeching Swarm does as damage, p is the proportion of players affected by Penetrating Cold at cast and P is the tick size of Penetrating Cold, the steady-state health level H* is H* = ¹/_r(h - ³/₁₀pP). It is a good idea to incorporate a buffer against the randomness of the damage.
• For Heroic 10-man, the steady-state health level is H* = 5h - 450, and for Normal 25-man, it is H* ~ 10h - 228.
• As long as the steady-state health level is more than zero, the healing the healers provide is sufficient.

The Healer's Skills Record

In my adolescence, I went to swimming lessons. I would learn various swimming skills and the instructor would keep track of my progress. At the end of the program, I received a certificate, overleaf a checklist of the skills being assessed. Ticked were the skills I managed to master, and unticked were the ones I still need to work on.

The listed skills were also sorted according to difficulty. In the above example, from easiest to hardest, the categories are Red, Yellow, Green and Blue. There was also a note that continual practice was needed to maintain mastery of the skills learnt.

Like swimming, the responsibility of providing healing to a group requires the mastery of several skills. Like swimming, some skills are more difficult than others. And like swimming, being a good healer requires continuous practice, not only to maintain current proficiency, but also improve on it. In the spirit of the above example, I have prepared a checklist of the many skills a healer needs in order to heal well. It assesses the following general criteria:

Riding Out the Swarm

The Heroic Anub'arak encounter places great strain on a 10-man raid attempting it. Teams with a relatively weak dps team may choose to bring two healers into it, placing a great burden on the healing team during Phase 3.

Phase 3 is notorious for Leeching Swarm that Anub'arak keeps up during this time. This is coupled with a heavily ticking Penetrating Cold debuff cast on three random players. Due to high-hitting melee attacks and Freezing Slash, one healer usually must focus 100% on healing the main tank, leaving the other healer handling the raid and the offtank. That raid healer has a hard job, though a few tips and tricks may make it much easier.

The Time-Value of Health

This blog post builds on the concepts suggested in 'Not All Hitpoints are Created Equal', helping to adjust healing for the health level of the recipient.

Experts in finance speak of the time-value of money. Under this concept, the value of a certain quantity of dollars (or other currency) will decrease as time passes. Many attribute this to the fact that people want money now rather than later. Therefore, to keep this time-value the same, interest must be paid on top of this quantity of dollars.

Hitpoints restored by healing also seem to have this time-value, since a heal of the same size will be more valued the sooner it is received (considering that people wish to keep their health at a maximum). How should such heal weighting be done?

Not All Hitpoints are Created Equal

There is always question on whether the output of healing meters (healing charts) can be used in indicating a healer's performance. Unlike points of damage, where heals go matters. While everyone has use for a heal, some players will need it more than others.
 Healing meters (such as the 'Healing done' component of Recount) collect raw figures from the combat log. It becomes easy to assert, from skimming over the healing chart, that all hitpoints (HP) are created equal, with all players appreciating 1 HP of healing equally. However, I would not.

1. Factoring in absorptions
When a player inevitably takes damage, a healer can respond to it in any of two ways:

The Clock-cycle Model of Chain Casting

Chain casting is an action where multiple spells are cast in succession with minimal delay between them. This is a crucial skill in raiding, where (provided that the person does not upset a mob's threat table) it improves individual performance, whether tanking, healing or dealing damage.

There are striking similarities between how one chain casts and how a computer's processor works. The following will draw parallels between the two, and may allow the chain casting process to be treated differently to frantic button-mashing. It would be important to know that the central processing unit (CPU) is the component of a computer that follows a series of instructions to produce a series of results. Only spells with cast times of some multiple of the global cooldown will be considered.

Processing an instruction <--> Spell casting
The instruction (in computing) is the atomic unit of a CPU's entire workload. the CPU can only digest one instruction at a time (though if it has n cores, it can process n instructions at the same time), and will do so in sequence.

When casting a spell, the player selects a target, decides which spell to cast and presses the appropriate button (in any order). The player does this repeatedly and sequentially while chain casting.

Clock generator <--> Global cooldown
A crystal oscillator which can provide a clock signal to a computer system.

By itself, the CPU has no concept of time and thus cannot process instructions (which take time). A clock generator provides a rhythm (the clock signal) to the CPU. As a certain amount of time passes between beats (clock cycles), the CPU can use this rhythm to perceive time. It will then process however many needed instructions in a clock cycle (or vice versa). The frequency of the clock generator is measured in hertz (Hz), or cycles per second.

The global cooldown (GCd) is the minimum time that needs to pass between spell casts, which (when not modified by Haste Rating or Bloodlust/Heroism) is 1.5 seconds. This corresponds to a frequency of 2/3 Hz. (As a side note, Haste Rating can reduce the GCd to 1 second and increase the frequency to 1Hz.) This GCd can provide a rhythm which avoids the need for button-mashing. Some long-cast spells (e.g. Greater Heal) take whole multiples of one GCd to cast, which can be spread over several multiples without losing the sense of rhythm (simply miss a few beats).

Clock multiplier <--> Chain casting ability

An interface showing a system's system clock settings.

The clock multiplier multiplies the clock rate by a certain number n, so that the clock signal actually used by the CPU is n times faster than the clock signal from the clock generator.

A novice player may be able to cast 1.5 second spells over 3 GCds (frequency of 2/9 Hz), which, if the GCd was used for the 'clock signal', would cast on a 'clock multiplier' of ~0.33.

Overclocking and resulting overheating <--> Practice and resulting fatigue
Overclocking the CPU involves setting its clock multiplier higher. This hastens the clock signal in use and causes the CPU to work faster. However, by working faster, the CPU also generates more heat. If it cannot withstand the heat, it will start introducing errors in its work.

With practice, the player can chain cast close to the maximum 'clock multiplier' of 1. However, if they keep this up, they will get tired (if done repeatedly, they may suffer burnout). In normal raiding, the practical maximum is not usually needed, and the player can afford to work suboptimally to keep their energy levels up.

Interrupt handling <--> Situational awareness
A (software) interrupt is an instruction for the CPU to stop processing a set of instructions (a process) and start processing another. It allows a single CPU to run several processes at the same time (multitask) by simply switching between them.

Raid encounters rarely involve simply casting spells at fast as possible. There are almost always random events to respond to. The player would chain cast as normal, then interrupt it to respond promptly to events needing attention. For example, a tank healer responsible for two or more tanks would need to switch constantly between them, devoting most of their attention to the target tank. Some attention would be reserved for recognising the healing needs of the other tank(s), as well as responding to the environment.

Something to consider
A Brunel University study found that working to a rhythm reduces fatigue. By casting in time with the GCd (or some other rhythm), less energy will be used and the player will be able to more easily sustain their performance in a raid.