Shield Block Testing

[Satrina]

I actually did this some time ago, not long after I hit 70. Ended up typing it all out today for someone else and Kazeyonoma was all dood, get that on Tankspot - so here it is:

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Test Methodology:
70 warrior: 492 Defense. 21.23% block, 16.86% dodge, 14.34% parry, 10.68% miss (142*0.04% + 5%)
60 Priest for heals.
One small addon that records incoming attack data in separate sets: while Shield Block is active / while Shield Block is not active

Need a mob that ideally:
- Performs crushing blows
- Does not require movement while tanking (see Crits & Crushes).
- Has no melee special attacks to mess with Shield Block charges

In the absence of an equivalent to Taelan Fordring that I used at level 60, I chose Doomwalker as the easiest to get to. He has abilities that knock you around but with a single healer, I died before he uses them anyway while usually being able to get a couple of rounds of shield blocked attacks in before dying. Chain lightning attack doesn't consume shield block so while it would end a round immediately, it did not waste results. The Mark of Death is a pain in the ass, but that's what a good book is for.

For a world boss, we account for decreased avoidance (0.6% per) and so have expected values of:
20.63% block, 16.26% dodge, 13.74% parry, 10.08% miss

Tests were performed by buffing with available stamina buffs (PW:F, Commanding Shout, Elixir of Fortitude). Abilities that affect damage taken and/or health but not type of hit taken were used as available from cooldowns (healing potions, pre-nerf Lifegiving Gem, Last Stand, Shield Wall). A goal of 3000 shield blocked attacks and 3000 non-shield blocked attacks was set for data collection. After collecting 3000 shield blocked attacks, Doomwalker was repeatedly engaged without activating shield block to reach the data set goals

Test Execution:
With Shield Block: Bloodrage then Commanding Shout. Allow Bloodrage cooldown to finish and lost health to regenerate. Approach Doomwalker with Bloodrage, activate Shield Block on each cooldown until death with priest healing, keep Demoralising Shout and Improved Thunderclap up. Run back, resurrect, wait for debuff, repeat.

Without Shield Block: Bloodrage then Commanding Shout. Allow Bloodrage cooldown to finish and lost health to regenerate. Approach Doomwalker until death with priest healing, keep Demoralising Shout and Improved Thunderclap up.. Run back, resurrect, wait for debuff, repeat.


Test Results:

Shield Block Active

Attacks:        3002
Misses:          305 (10.16%)
Dodges:          481 (16.02%)
Parries:         402 (13.39%)
Blocks:         1814 (60.43%)
Critical Hits:     0 (00.00%)
Crushing Blows:    0 (00.00%)

Shield Block Not Active

Attacks:       3000
Misses:         310 (10.33%)
Dodges:         485 (16.17%)
Parries:        414 (13.80%)
Blocks:         625 (20.83%)
Critical Hits:    0 (00.00%)
Crushing Blows: 452 (15.07%)
Normal Hits:    714 (23.80%)

Results:
As expected, shield block still removes crushing blows from the table given sufficient supporting avoidance to exceed 102.4% total.

Observe that 25% block is not required to remove crushing blows from the table. (Mere pedantic confirmation as we already knew that paladin tanks are uncrushable without 100% block.)

No critical hits were observed in the testing. In the case of Shield Block active this is consistent with expectation, as removing crushing blows from the table would also remove critical hits from the table, regardless of defense score. In the case of Shield Block not active, this is consistent with 490 defense removing critical hits from the combat table.

However, it must be noted that statistically, if a 0.1% chance of critical hit were indeed always present on the combat table, we could expect to see 3 critical hits over the sample of 3000 non-shield blocked hits. Of course, given the statistical variance in observed results (e.g. 10.33% observed miss rather than 10.08% expected) it is possible that the low expected value simply did not appear in this round of testing. In the case of a 0.01% chance of critical hit remaining on the table, we would expect to not see one in this sample set size in any case.*


* That said, this far into TBC and only seeing certain mobs landing crits against 490+ defense, I still submit that increased critical hit chance is the correct answer, and not "always a small chance". Even at 0.01%, by now we would be seeing many more reported critical hits than we have seen. This is, of course, opinion and nobody outside of Blizzard knows the fact of it.

[Ciderhelm]

Ninja-stuck.

[Nicki]

Nice too see this time to start linking on the warrior forums i guess...(if im bored enough too) might cut the 25% block posts in half...

BTW...Taelon fordring can still land crushing blows /comfort!

[Fame]

Comparing both the tables, when SB wasnt active it seems that your avoidance was higher. Is that just pure luck of the RNG or is there supportive information out there that somehow shows that SB will override other avoidance stats on the hit table? I was under the impression that Black comes last on the table (Illidan and Shear clearly shows that.) So taking this to the next step, a boss that can't Crush (Archimonde for example) would not using SB be better in the end? Or is the loss in avoidance negligible for the amount you are going to block for at the end of the fight if you were to have SB active?

[Satrina]

It's just the luck of the RNG. If you look at the absolute numbers, it's only 5 more misses, 4 more dodges, etc. between the two sets. It could have easily been fewer than the expected numbers as well.

I wouldn't waste rage on shield block against non-crushing bosses, it costs you TPS.

[Nicki]

However shield block is guarenteed mitigation but i suppose once its farm status you dont need to max mitigation *shrugs*

[Narshe]

This work is awesome. Not only for the info but the way it was gathered. I admire your patience and dedication and I won't offer my babies because my GF wouldn't like the idea xDDD

I will post this on Spanish official forums. Anyone going for EJ? :P

[Kazeyonoma]

thanks dood

:P

Just easier for us to reference for people who argue against stacking avoidance %.

I guess my hotkeys macro's that auto press shieldblock for me are hurting me in my non-cb mobs rage gen. I just love completely blocking incoming damage though!

[Monster] Attacks you. You [block].

>;]

[Gruffian]

To say that shield blocking on non CBing mobs is a waste is a bit far from the truth.

Archimonde for example, doesnt crush, but not using SB every time its up would be a waste. You're talking about shaving 500ish damage off each attack (SBV pending).

If anything the test validates using SB no matter what, because you will not suffer any penalties on your avoidance.

This is stuff most of us have held as relative truths when it comes to tanking, but its awesome to see hard data confirming it. Great job as usual Satrina, your work continues to go very much appreciated.

[Nicki]

archmonde hits for 9k right?

9000-500/9000=5.5% damage reduction

Right thats a waste of 5 rage, is it?

[Horacio]

archmonde hits for 9k right?

9000-500/9000=5.5% damage reduction

Right thats a waste of 5 rage, is it?

I would think rage is not an issue either way(meaning, having virtually unlimited rage) and its more a matter of managing cooldowns and rotations...in which case, I would imagine the decision whether or not to SB has more to do with your TPS and the threat by your DPS. IE, if you can maintain a significant lead in threat, why not mitigate some additional incoming damage. I'm not speaking specifically about one encounter but in a broad sense.

[Wartorn]

Hate to bring up Farstrider v GTC v Devilshark v Phoenix again, but when you're virtually uncrushable, isn't there some point (armor class) when the pure SBV on Farstriders becomes superior to mitigation from armor on the other cloaks?

[Satrina]

Perhaps waste was a bit strong in statement. How about this:

You should definitely look at the use of shield block against non-crushing mobs in contrast to the TPS you trade for using it

Better? =)

However, I'll leave you with this to chew on: We advocate stamina/armour over avoidance on the basis that your healers are already healing the damage you'd avoid anyway. Why is this case any different than that one? I know that the mitigation from the shield blocks are guaranteed and all, but the healers are still healing for 9k hits anyway.

[Wartorn]

I assume it's because it's a predictable amount of damage being healed/avoided.

[Rak]

Because you're not avoiding the attack, just a small percentage of it's damage. I could argue the same thing in regards to armor: it 'avoids' a percent of damage from incoming hits.

I don't consider blocks avoidance at all, just like I don't consider armor to be avoidance. Maybe if you block 100% of the damage from a hit it could be called avoidance, but that's not the issue here. I played a priest from release through Naxx, and I'm going to have to say that chain casting heals non-stop to cover 9000 incoming damage and 8500 incoming damage isn't even noticeable to me personally.

When you avoid an entire attack, you will go one or two seconds with nothing but pure overhealing. When you block 5% of an attack's damage, you will receive the same amount of seconds being overhealed as you would have if you had not blocked that 5%. I mean, 500 damage is less than a renew tick.

[Satrina]

I'm going to have to say that chain casting heals non-stop to cover 9000 incoming damage and 8500 incoming damage isn't even noticeable to me personally.

Exactly what I am getting at.

Edit:
- Horacio's comment is good, too. If I have like 50k threat over the next person, then throwing a bit of rage on SB won't hurt, sure.
- I can't say I've tanked Archimonde yet, but I certainly have no trouble burning all my rage on 6-7k hits if I want to.

[Rak]

Ok, then why does armor matter? If increasing my armor will make me take 5% less damage per hit, the healers won't even notice it. Isn't this the same idea? Isn't shield block just basically increasing your effective health in a more static way?

[Wartorn]

Exactly what I am getting at.

Edit:
- Horacio's comment is good, too. If I have like 50k threat over the next person, then throwing a bit of rage on SB won't hurt, sure.
- I can't say I've tanked Archimonde yet, but I certainly have no trouble burning all my rage on 6-7k hits if I want to.

I guess what I'm trying to say is that healers can adjust for it. The same is not true for pure avoidance.

[Satrina]

You're missing the context here. We are talking about using shield block for extra mitigation at the expense of threat generation. It's not free. I had initially said it's a waste, which may be a bit strong. I'd still tend to spend the rage on threat instead of blocks - but it will depend on the fight I suppose.

Edit: And it's not a static amount. You can still be missed, dodge, or parry the attack if shield block is up. And the healers are still healing.

Ultimately, it's a choice that can't be wrong whichever you choose.

[Rak]

That's true, I suppose. I could argue that armor reduces rage generation too... but I won't, because it wouldn't hold up. I've never really worried about SB costing me threat except on trash, so I guess I just don't think about it much.