Proc Coefficient

The proc coefficient is the factor by which an item's effect, trigger chance, duration, or any combination of the three is scaled (multiplied).

This affects how certain "hits" can be "worse" or "better" at activating on-hit effects, depending on how high (or low) the proc coefficient is. If something hits very frequently, it may have a lower proc coefficient to lower the power of the ability to not outclass other abilities. Conversely, an infrequent, hard-hitting ability may have a higher proc coefficient to make up for the fact that it doesn't hit too often.

This also means that a character may need more than 100% "chance" from a collection of items to guarantee that desired proc.

In Hopoo Games Development Thoughts #1, the developers introduced the concept of proc coefficient like so:

"MUL-T’s nailgun has a low proc coefficient per nail of 0.4 compared to most character’s 1.0, so he isn’t proccing stuff a ton faster than other characters." - Quote from NaKyle, 03/30-2019.

(Note: Since the 1.0 update, MUL-T's nailgun has a proc coefficient of 0.6 rather than 0.4. The quote is given primarily as rationale for the proc coefficient system.)

It is worth noting that proc coefficients do not affect critical strike chance from items such as Lens-Maker's GlassesLens-Maker's Glasses
Gain 10% chance for hits to 'Critically Strike', dealing double damage.
Your attacks have a 10% (+10% per stack) chance to 'Critically Strike', dealing double damage.. All attacks are guaranteed to deal critical damage once 100% critical chance is reached.

Examples

Example 1

Suppose that a bullet has a proc coefficient of 0.5, and we have 1 Tri-Tip DaggerTri-Tip Dagger
Gain +10% chance to bleed enemies on hit.
10% (+10% per stack) chance to bleed an enemy for 240% base damage.. The dagger normally contributes a +10% chance to inflict BleedBleed (Debuff)
Damage over time.Deals 240% damage over time [3 x proc coefficient] (20% per tick, 4 ticks per second).
(stackable) on the victim for 3 seconds. However, with a proc coefficient of 0.5, the chance to inflict Bleed is halved (since we multiply that chance by 0.5), so the bullet's chance to inflict Bleed is only 5%. Additionally, the duration of Bleed is also halved, so even if the bullet does successfully roll the 5% infliction chance, the Bleed status will only last 1.5 seconds instead of 3.

Example 2

Suppose we have the same bullet with a proc coefficient of 0.5, but this time we have 18 Tri-Tip DaggerTri-Tip Dagger
Gain +10% chance to bleed enemies on hit.
10% (+10% per stack) chance to bleed an enemy for 240% base damage., totaling +180% bleed chance. With the proc coefficient of 0.5, this makes the bullet have a 90% chance to inflict Bleed, instead of 100%. This means that we will need at least 20 daggers to guarantee Bleed from this bullet. Additionally, the duration will still be halved (1.5 seconds), no matter how many daggers we have.

Key Points

• A character with skills that have lower proc coefficients will require more items to reach a similar effect than skills with higher coefficients, but those caps for effects with linear stacking can still be reached.
• Skills and effects with low proc coefficients often hit faster than normal or hit more than one target. Because of this, those skills and effects may tend to be more effective at utilizing item effects with linear stacking for their trigger chance (notably Bleed effects) than those with higher coefficients but that hit slower or hit fewer targets. The caveat is, of course, that these skills require a greater investment required to reach their maximum potential. Exceptions also exist; for instance, many of Commando'sCommandoThe Commando is a jack-of-all-trades character that is reliable in all situations of the game.
  Class: Ranged
  HP: 110 (+33 per level)
  Damage: 12 (+2.4 per level)
  Armor: 0
  Umbra: Cornered Gunslinger skills hit very quickly but also have very high coefficients.
• Critical strike chance is not affected by the proc coefficient.

For more information on item stacking mechanics and strategies, see Item Stacking.

Proc Coefficient Effects

See also: Item Stacking

Items that are affected by proc coefficient and how they are affected:

Item	Effect
Tri-Tip Dagger	Chance and duration of BleedBleed (Debuff) Damage over time.Deals 240% damage over time [3 x proc coefficient] (20% per tick, 4 ticks per second). (stackable)
Stun Grenade	Chance to stun
Sticky Bomb	Chance to stick a bomb
AtG Missile Mk. 1	Chance to fire a missile
Ukulele	Chance to shoot lightning
Leeching Seed	Healed amount
Predatory Instincts	Duration of Attack Speed On CritAttack Speed On Crit (Buff) Gain additional attack speed.Gain +12% attack speed. (stackable)
Harvester's Scythe	Healed amount
Brilliant Behemoth	Explosion's radius
Sentient Meat Hook	Chance to shoot hooks
Wake of Vultures	Blazing elite: Duration of BurnBurn (Debuff) Damage over time, disable health regeneration.Applies a percent of damage over time, and disables health regeneration. (stackable) Glacial elite: Duration of 80% Slow80% Slow (Debuff) Reduces movement speed by 80% (in practice, 45.5%).
Shattering Justice	Duration of Pulverize BuildupPulverize Buildup (Debuff) Upon getting 5 stacks, reset all stacks and apply the Pulverized debuff. (stackable)
Brittle Crown	Chance to gain gold
Ifrit's Distinction	Duration of Burn
Her Biting Embrace	Duration of 80% Slow
N'kuhana's Retort	Duration of Healing DisabledHealing Disabled (Debuff) Disables healing.Disables all healing, including base health regeneration and item regeneration.
Spectral Circlet	Duration of 80% Slow
Shared Design	Duration of CrippleCripple (Debuff) Reduces armor by 20. Reduces movement speed by 50%.

Survivors

A list of all the proc coefficients for each skill, for each survivor.

Acrid

	Skill	Proc Coefficient
	Vicious Wounds	1.0 x 3
	Neurotoxin	1.0
	Ravenous Bite	1.0
	Caustic Leap	Leap: 1.0 Pool: 0.1
	Frenzied Leap	1.0
	Epidemic	1.0

Artificer

	Skill	Proc Coefficient
	Flame Bolt	1.0
	Plasma Bolt	1.0
	Charged Nano-Bomb	Explosion: 1.0 Sparks: 0.3
	Cast Nano-Spear	1.0
	Snapfreeze	1.0 x 12
	Flamethrower	1.0 x 22+
	Ion Surge	1.0

Bandit

	Skill	Proc Coefficient
	Burst	0.5 x 5
	Blast	1.0
	Serrated Dagger	1.0
	Serrated Shiv	1.0
	Smoke Bomb	1.0 x 2
	Lights Out	1.0
	Desperado	1.0

Captain

	Skill	Proc Coefficient
	Vulcan Shotgun	0.75 x 8
	Power Tazer	1.0
	Orbital Probe	1.0
	OGM-72 'DIABLO' Strike	1.0
	Orbital Supply Beacon	0.0

Commando

	Skill	Proc Coefficient
	Double Tap	1.0
	Phase Round	1.0
	Phase Blast	0.5 x 8
	Suppressive Fire	1.0 x 6+
	Frag Grenade	1.0

Engineer

	Skill	Proc Coefficient
	Bouncing Grenades	1.0
	Pressure Mines	1.0
	Spider Mines	1.0
	Thermal Harpoons	1.0 x 4
	TR12 Gauss Auto-Turret	1.0
	TR58 Carbonizer Turret	0.6

Huntress

	Skill	Proc Coefficient
	Strafe	1.0
	Flurry	0.7 x 3 (0.7 x 6 on critical strike)
	Laser Glaive	0.8 per bounce
	Arrow Rain	0.2 x 19
	Ballista	1.0 x 3

Loader

	Skill	Proc Coefficient
	Knuckleboom	1.0
	Spiked Fist	1.0
	Charged Gauntlet	1.0
	Thunder Gauntlet	1.0
	M551 Pylon	0.5
	Thunderslam	1.0

Mercenary

	Skill	Proc Coefficient
	Laser Sword	1.0
	Whirlwind	1.0 x 2
	Rising Thunder	1.0
	Blinding Assault	1.0
	Focused Assault	1.0
	Eviscerate	1.0 x 7+
	Slicing Winds	1.0 x 8

MUL-T

	Skill	Proc Coefficient
	Auto-Nailgun	0.6
	Rebar Puncher	1.0
	Scrap Launcher	1.0
	Power-Saw	1.0
	Blast Canister	Canister: 1.0 Bomblets: 0.3 x 5
	Transport Mode	1.0

REX

	Skill	Proc Coefficient
	DIRECTIVE: Inject	0.5 x 3
	DIRECTIVE: Drill	0.5 x 16
	Seed Barrage	1.0
	DIRECTIVE: Disperse	0.0
	Bramble Volley	0.5
	DIRECTIVE: Harvest	1.0
	Tangling Growth	Projectile: 1.0 Roots: 0.0

Railgunner

	Skill	Proc Coefficient
	XQR Smart Round System	1.0
	M99	1.0
	HH44	1.0
	Supercharged Railgun	3.0
	Cryocharged Railgun	1.5
	Concussion Device	0.0
	Polar Field Device	0.0

Void Fiend

	Skill	Proc Coefficient
	Drown	1.0
	Corrupted Drown	0.625
	Flood	1.0
	Corrupted Flood	1.0

Items

List of items that have effects that also have a proc coefficient.

• Damage-over-time effects, such as BleedBleed (Debuff)
  Damage over time.Deals 240% damage over time [3 x proc coefficient] (20% per tick, 4 ticks per second).
  (stackable) and BurnBurn (Debuff)
  Damage over time, disable health regeneration.Applies a percent of damage over time, and disables health regeneration.
  (stackable), have a proc coefficient of 0.0 and thus will never activate other effects.

Item	Proc Coefficient
Bundle of Fireworks	0.2 x 8 (+4 per stack)
1 Gasoline	0.0
Sticky Bomb	0.0
AtG Missile Mk. 1	1.0
Runald's Band	0.0
Kjaro's Band	0.0
Razorwire	0.5
Shuriken	1.0
Ukulele	0.2
Will-o'-the-wisp	1.0
Brilliant Behemoth	0.0
Ceremonial Dagger	1.0 x 3
Frost Relic	0.2
N'kuhana's Opinion	0.2
Resonance Disc	Launch and return: 1.0 Explosion: 1.0
Sentient Meat Hook	0.33
Unstable Tesla Coil	0.3
Charged Perforator	1.0
Molten Perforator	0.7 x 3
Genesis Loop	1.0
Little Disciple	1.0
Shatterspleen	Explosion: 1.0
Disposable Missile Launcher	1.0 x 12
Fuel Array	0.0
Molotov (6-Pack)	Molotovs: 1.0 Fire Pools: 0.5
Preon Accumulator	Explosion: 1.0 Sparks: 0.1
Remote Caffeinator	1.0
Royal Capacitor	1.0
Sawmerang	Initial hit and hit on return: 1.0 Continuous damage: 0.2
The Back-up	0.0
The Crowdfunder	1.0
Volcanic Egg	1.0
Egocentrism	1.0
Glowing Meteorite	1.0
Helfire Tincture	0.0
Visions of Heresy	Initial hit: 0.1 Explosion: 1.0
Plasma Shrimp	0.2
Polylute	0.2
Singularity Band	1.0
Voidsent Flame	1.0
Ifrit's Distinction	0.0
Silence Between Two Strikes	0.0
Her Biting Embrace	0.75 (death explosion)
N'kuhana's Retort	1.0 (from post-death Malachite UrchinMalachite Urchin HP: 250 (+75 per level) Damage: 18 (+3.6 per level) Class: Ranged Speed: Unknown m/s Armor: 100)

Notes: