Proc Coefficient

Definition
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 proccing 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.)

Important note for crit chance
It is worth noting that proc coefficients do not affect critical strike chance from items such as. Once you have at least 100% crit chance, you are guaranteed to crit.

Example 1
Suppose that a bullet has a proc coefficient of 0.5, and we have 1. The dagger normally contributes a +10% chance to trigger a bleed effect. However, with a proc coefficient of 0.5, the chance to bleed is halved (since we multiply that chance by 0.5). Then the chance to trigger a bleed is 5% with that bullet.

Example 2
Given the same bullet from example 1 with a proc coefficient of 0.5, but this time we have 18 contributing to a +180% bleed chance. With the proc coefficient of 0.5, this makes the bullet have a 90% chance to bleed, instead of 100%. This means that we will need at least 20 daggers to guarantee a bleed from this bullet.

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  skills hit very quickly but also have very high coefficients.
 * Again we reiterate that crit chance is not affected by 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:

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

Items
List of items that have effects that also have a proc coefficient. Notes:
 * Damage-over-time effects, such as and, have a proc coefficient of 0.0 and thus will never activate other effects.