# League of Legends Preseason 2021 Changes: Part One — Ability Haste

Hello! Last Light here. This will be a multi-part series where I will talk about the expected preseason changes and do a mix of analysis and prediction based on this article Riot recently released.

This first part is going to talk about the new concept of “Ability Haste.” I’m going to explain how it compares to CDR, how to understand it intuitively, relate it to Damage Resistances, and then make a few predictions.

Ability Haste is replacing Cooldown Reduction (CDR). The current state of CDR scales non-linearly. This isn’t immediately intuitive as 10% CDR sounds like 10% more spells. However, each consecutive percent of CDR is worth more than the last. Instead we have Ability Haste (AH) or how many more spells you can cast. Here’s a table showing some breakpoints.

So as you can see, each point of CDR increased in value. People see “10% CDR” and think “10% more casts” which is untrue. With Ability Haste, 10 AH will mean 10% more casts. 100 AH means 100% more casts, or twice as many. Using this tweet as a reference for the formulas.

CD = baseCD/(1+[AH/100])

Casts per baseCD = 1+[AH/100]

The first formula is more complicated, but gives you the cooldown, the second formula is for understanding the damage increase. The advantage of this system is that it more closely matches what players think is happening when they buy CDR/AH, but it comes at the cost of intuitively knowing what the actual cooldown of an ability is. In addition, we will have to relearn that 40–45 AH is the break-point for Riven to infinitely cast Broken Wings, rather than 30%.

# How this relates to Damage Resistances

Let’s go ahead and backtrack a little bit to those formulas. They may look familiar to anyone who has done the math on Armor or Magic Resist. From here on, anything about armor can be applied to Magic Resist as well.

Damage Multiplier = 1/(1+[Armor/100])

Damage Reduction = 1 — Damage Multiplier

The above formula can be used to calculate damage reduction, which again suffers from a misunderstanding from the player base. 25 armor results in a 20% reduction (0.8 multiplier) while 100 armor results in a 50% reduction (0.5 multiplier). This has caused the misunderstanding that “Armor has diminishing returns.” This is not true. Each point of armor is worth 1% more effective health against physical damage. The formula looks like this.

Effective Health Points = (1+ [Armor/100])x Health Points

This may look familiar. It looks a lot like the formula for Ability Haste.

Let’s give some examples to clarify as people do not intuitively understand percentages. If a champion has 1000 Health Points (HP) and they buy 10 Armor, it increases by 10%, bringing them to 1100 Effective Health Points (EHP). If they purchase an additional 10 Armor, it increases again by 10%, of the original health pool, to 1200 EHP. If we continue this trend to where the champion purchases 10 Armor to go from 100 to 110 Armor, the EHP increases from 2000 to 2100. As an overall percentage, this was an increase of only 5% EHP rather than 10% like it originally was. In the same way that a pay raise from $10 to $11 is a 10% raise, a pay raise from $100 to $101 is only a 1% raise. The dollar still carries the same purchasing power, it does not have diminishing returns. However, when we make efficiency comparisons, we will find that purchasing a mix of Health and Armor will give the most overall tank stats. Whenever you have a multiplicative relationship, increasing the lower of the two bases will give a greater result.

# Prediction time!

This is just for fun, honestly. I’m expecting somewhere between 10–20 AH available in runes, and an AH focused build to provide about 100AH, leaving an AH focused build around the equivalent of 50% CDR. I think we’ll see a number of items have about 10–15 AH to keep the “CDR feels nice” feeling that League has as the game progresses, but the items that focus on AH with power tradeoffs to be at 20–25AH. We’ll probably see Cloud Drake still giving something like 10 AH for ultimates. Remember when we go from 100AH to 200AH it’s going from 50% CDR to 66% CDR, so even if those extreme cases cap out around 200AH for ultimates, it’s still within the range that already exists in the current state of the game.

I think this is an overall positive change and makes it easier on the balance team to add more Ability Haste into runes and other places. Moving from 150AH to 160AH is far less impactful than 40% to 45%, so it gives Riot a lot more wiggle room.

The next article will be an analysis on current mage items, and expectations for what we can expect for first item choice (including the Ability Haste changes), and an exploration into what Artillery Mages may have (Xerath, Ziggs, and possibly Lux?)