Edit: Debunking that SH is less useful with higher EV
Posted: Sunday, 29th July 2018, 00:23
Spoilered this because otherwise people think I am mathematically modelling the entrety of crawl for some reason
What I am interested is is debunking that SH is less useful innately if EV is high.
In probability theory, EV = chance to fail to evade. EV = (1 - chance to evade)
In probability theory, SH = chance to fail to shield. SH = (1 - chance to shield).
Assume that EV and SH are equal to each other and operates in the exact same way.
Assume that EV and SH operates by having a chance to prevent each attack.
---
Imagine that the "power level" of defence is the effective HP that is created to withstand an attack.
Personally I don't like using % as it adds a layer of confusion that tends to confuse people.
Imagine HP = 100. If EV would prevent half of attacks, then survivability is doubled, time to be killed is doubled.
That is to say that effective HP is 200% An alternative is to say that that effective HP is doubled to 200 HP.
---
Actually I think a more useful descriptor of "power level" of defence would be "Time taken before dying". The greater the time taken before dying, the more powerful defences are.
So T = Time taken before dying.
Standard T = 1
EV =0.5, then T = 2
I hope we can all agree on this.
If EV prevents a third of all attacks then time taken before dying is 3 times longer than before.
If EV would prevent a quarter of all attacks, then the time taken before dying would be 4 times longer than before.
If EV = 0.25, then T = 4.
If EV = 0.2 (a fifth), then T = 5
If EV = (a sixth) then T = 6
If EV = (a seventh) then T = 7
If EV = (an eigth) then T = 8
If EV = (A ninth) then T =9
If EV = 0.1, then T = 10
If EV = 0.01 then T = 100
If EV = 0.001 then T = 1000
If EV = 0, then T = infinity
Meaning that if you prevent every single attack from hitting your character then you will never die. This is not debateable.
---
The simple thing to plug into your calculator or pen and paper or mental arithmetic is T = (1/EV)
Likewise if EV = 1, then T = (1/SH)
Due to the assumption that EV and SH operates by preventing an attack, the method to find the new time taken before dying is :
T = (1/EV) x (1/SH)
---
Example character A: Chance to evade is 30%. EV = chance to fail to evade. EV = (1 - chance to evade). Chance to evade is 30%, which is P= 0.3. EV = (1 - 0.30), therefore EV = 0.7
Time taken before dying = (1/EV) = (1/0.7) = 1.43
Example character B; Chance to evade is 70%. EV = chance to fail to evade. EV = (1 - chance to evade). Chance to evade is 70%, which is P= 0.7. EV = (1 - 0.70), therefore EV = 0.3
T = (1/EV) = (1/0.3) = 3.33
---
Hopefully as noticed, character B, with a 70% chance to evade has greater time taken before dying that character A. What we want to look at is the impact of the chance to shield an attack. Lets take that probability to shield an attack is 20% chance.
For both @A and @B, the probability to shield an attack is 20%. SH = chance to fail to shield. EV = (1 - chance to shield). P= 0.2. EV = (1 - 0.20), therefore EV = 0.8
T = (1/EV) = (1/0.8) = 1.25
As can be seen, rather unsuprisingly, a 20% chance to shield is less useful than either a 30% chance to evade or a 70% chance to evade. However what we are interested in is the impact of SH. It's not neccesary in actuality, but for the sake of completeness.
---
For @A, T = (1/EV) x (1/SH)
T = (1/0.7) x (1/0.8) = 1.78
Impact of shield = (time taken before dying with shield / time taken before dying without shield) = 1.78 / 1.43 = 1.25
(Actual numbers used, not rounding error used)
For @B, T = (1/EV) x (1/SH)
T = (1/0.3) x (1/0.8) = 4.17
Impact of shield = (time taken before dying with shield / time taken before dying without shield) = 4.17 / 3.33 = 1.25
The 25% increase in effectiveness for both characters A and B is not suprising because the maths used is very simple, but the explanation and refutation behind it less so.
Btw, when dodge probability reaches 100%, time to die is infinity, and so a shield will increase the time dying to infinity x 1.25, which is still infinity, but a different type of infinity. Infinity is funny like that.
---
There's several other ways of explaining this like the "effective HP" method.
If anyone wants further explanation at any point, point out any mistakes seen, please do so, and I'll explain/rectify it.
Spoiler: show
What I am interested is is debunking that SH is less useful innately if EV is high.
In probability theory, EV = chance to fail to evade. EV = (1 - chance to evade)
In probability theory, SH = chance to fail to shield. SH = (1 - chance to shield).
Assume that EV and SH are equal to each other and operates in the exact same way.
Assume that EV and SH operates by having a chance to prevent each attack.
---
Imagine that the "power level" of defence is the effective HP that is created to withstand an attack.
Personally I don't like using % as it adds a layer of confusion that tends to confuse people.
Imagine HP = 100. If EV would prevent half of attacks, then survivability is doubled, time to be killed is doubled.
That is to say that effective HP is 200% An alternative is to say that that effective HP is doubled to 200 HP.
---
Actually I think a more useful descriptor of "power level" of defence would be "Time taken before dying". The greater the time taken before dying, the more powerful defences are.
So T = Time taken before dying.
Standard T = 1
EV =0.5, then T = 2
I hope we can all agree on this.
If EV prevents a third of all attacks then time taken before dying is 3 times longer than before.
If EV would prevent a quarter of all attacks, then the time taken before dying would be 4 times longer than before.
If EV = 0.25, then T = 4.
If EV = 0.2 (a fifth), then T = 5
If EV = (a sixth) then T = 6
If EV = (a seventh) then T = 7
If EV = (an eigth) then T = 8
If EV = (A ninth) then T =9
If EV = 0.1, then T = 10
If EV = 0.01 then T = 100
If EV = 0.001 then T = 1000
If EV = 0, then T = infinity
Meaning that if you prevent every single attack from hitting your character then you will never die. This is not debateable.
---
The simple thing to plug into your calculator or pen and paper or mental arithmetic is T = (1/EV)
Likewise if EV = 1, then T = (1/SH)
Due to the assumption that EV and SH operates by preventing an attack, the method to find the new time taken before dying is :
T = (1/EV) x (1/SH)
---
Example character A: Chance to evade is 30%. EV = chance to fail to evade. EV = (1 - chance to evade). Chance to evade is 30%, which is P= 0.3. EV = (1 - 0.30), therefore EV = 0.7
Time taken before dying = (1/EV) = (1/0.7) = 1.43
Example character B; Chance to evade is 70%. EV = chance to fail to evade. EV = (1 - chance to evade). Chance to evade is 70%, which is P= 0.7. EV = (1 - 0.70), therefore EV = 0.3
T = (1/EV) = (1/0.3) = 3.33
---
Hopefully as noticed, character B, with a 70% chance to evade has greater time taken before dying that character A. What we want to look at is the impact of the chance to shield an attack. Lets take that probability to shield an attack is 20% chance.
For both @A and @B, the probability to shield an attack is 20%. SH = chance to fail to shield. EV = (1 - chance to shield). P= 0.2. EV = (1 - 0.20), therefore EV = 0.8
T = (1/EV) = (1/0.8) = 1.25
As can be seen, rather unsuprisingly, a 20% chance to shield is less useful than either a 30% chance to evade or a 70% chance to evade. However what we are interested in is the impact of SH. It's not neccesary in actuality, but for the sake of completeness.
---
For @A, T = (1/EV) x (1/SH)
T = (1/0.7) x (1/0.8) = 1.78
Impact of shield = (time taken before dying with shield / time taken before dying without shield) = 1.78 / 1.43 = 1.25
(Actual numbers used, not rounding error used)
For @B, T = (1/EV) x (1/SH)
T = (1/0.3) x (1/0.8) = 4.17
Impact of shield = (time taken before dying with shield / time taken before dying without shield) = 4.17 / 3.33 = 1.25
The 25% increase in effectiveness for both characters A and B is not suprising because the maths used is very simple, but the explanation and refutation behind it less so.
Btw, when dodge probability reaches 100%, time to die is infinity, and so a shield will increase the time dying to infinity x 1.25, which is still infinity, but a different type of infinity. Infinity is funny like that.
---
There's several other ways of explaining this like the "effective HP" method.
If anyone wants further explanation at any point, point out any mistakes seen, please do so, and I'll explain/rectify it.