=====Stacking Penalty=====

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=====Overview=====
**Stacking Penalty** is the effect of diminishing returns on the the use of **multiple** modules which affect the **same** attribute. Whether a module or rig is effected by stacking penalties will be explicitly stated in the item description. 

Stacking Penalties are applied at an attribute level, i.e. two different modules that similarly affect the same attribute will apply stacking penalties. For example, a Tracking Computer with a Optimal range script and a Tracking Enhancer will only suffer stacking penalties on the Optimal Range+Falloff attribute while the others remain unaffected by the diminishing returns.

Order of module activation is not considered for stacking purposes. The largest bonus takes precedent, making it the “first” module.

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=====Mechanics=====
====Stacking Penalty Type====
There are 3 known separated stacking groups. Each group is mutually exclusive to itself when bonuses are calculated:

  * **Friendly Module stacking**
   Any modules on a ship with stacking penalties fit into here (e.g. Sensor Boosters, Gyrostabilizers), as well as projected effects which boost the ships attributes.
  * **Offensive Module Stacking**
   This is identical to the first group, except it only applies to offensive modules, such as target painters or sensor dampeners.
  * **Non-Penalized Modules**

Modules that apply a raw value and do not state stacking penalties in the description. 

<WRAP center round info 60%>
The Damage Control and Reactive Hardener module only stack against each other. This is why you see almost every single PVP ship fit with a briefcase, and many capitals and Supercapitals fit with reactive hardeners.
</WRAP>


====Stacking Penalty Formula====

From a purely numerical standpoint- the formula and values are simple, however becomes more complex as you apply the stacking penalty to a cumulative increase:

<WRAP center round box 60%>
S( n ) = 0.5^[ ( ( n - 1 ) / 2.22292081 ) ^2 ]
</WRAP>


{{:training:stacking_penalty.png|}}

^Modules^Effect of nth module^
| 1| 100%|
| 2| 87%|
| 3| 57%|
| 4| 28%|
| 5| 10.5%|
| 6| 3%|

At the 6th module you hit the **Stacking Ceiling**. Further mods will not increase the attribute. 

Something important to note is that the effects stack multiplicatively, meaning each previous modules effect is taken into account for calculating the next. Due to this order of operation, the second and third modules provide a greater effect then the first.

====Target Painting Example====
In this example we use the a Target Painting Vigil versus an untanked Scimitar- assuming perfect skills each Target Painter on a Vigil increases the Scimitar's signature radius by 46.88%. The first Target Painter increases the Scimitar's Signature from 65 to            95.5. A difference of 30.5. The second increases the Signature from 95.5 to 134. A difference of 38.5.

This results in a Stacking Penalty ceiling of a sig of 205. Whereas with a static bonus (285% of a 46.88 increase) it should be ceiling of 151.

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=====Increasing The Stacking Penalty Ceiling=====
You should very rarely actually be in a position where you are hitting the stacking penalty ceiling- if you are you are either in a large fleet where you need redundancy in case of critical ships dying or are trying to maximize an attribute at the expense of all others. The latter tends to be a bad way to make fits. Before stacking penalties existed players were able to abuse modules to exponentially increase the performance of their ships.

Since you cannot increase the stacking penalty with more modules post-stacking ceiling, you have to increase the effectiveness of the modules you are using to have a greater effect:

  * Ship Bonuses, e.g. Webifier's on a Vindicator. The 90% velocity factor.
  * Fleet/Leadership Bonuses, e.g. Infolinks on Target Painters. 
  * Overheating, e.g. active hardeners.
  * Skills, e.g. The Sensor Disruption skill for Sensor Dampeners. 
  * Officer/Deadspace/Faction Modules, e.g. Your loot Pinata of a ratting ship.

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=====Item Types=====
====Items Unaffected By Stacking Penalties====
Most modules are affected by stacking penalties- however there are a few notable exceptions:

  * DPS applied to hostile ships.
  * ECM applied to hostile ships. 
  * Any attribute that is increased by an absolute (raw) value. Plates/Shield Extenders, Drone Control Units, Warp Core Stabs, and Local/Remote reps to list some. However their drawbacks may be affected such as the penalties to a Warp Core Stab. 
  * Fitting modules such as Ancillary Current Routers and Overclock rigs.
  * All drugs, boosters, and implants (except the Snake set).
  * Various Rigs are unaffected by Stacking Penalties. Tracking rigs only stack with themselves and not other tracking modules.

====Bonuses beyond Fitted Items or Projected Effects====
Not only are modules affected by stacking penalties, but ship stats and fleet bonuses can also contribute to diminishing returns. The most common culprit and situation you should bear in mind: resist bonuses.

Ship bonuses are subject to stacking penalties where applicable, a shield resist bonus is equivalent to a tech 1 Invulnerability field.
Fleet bonuses are also subject to stacking penalties- mind-linked Vulture shield resist boosts are equal to a faction Invulnerability field. 

For example: A single Invulnerability field fit on a properly bonused Drake is equivalent to having 3 Invulnerability Fields instead of one (25% from Hull Bonuses, 32.3% from the Vulture, and 30% from the Adaptive Invuln) . Any more than this is obviously going to start rapidly having diminished returns. This is an important consideration when decided that you want to fit a Damage Control.

^Ship Attribute^Is it Stacking-Penalized?^
| Powergrid (including reduced-PG-need effects)| no|
| CPU (including reduced-CPU-need effects)| no|
| Cargo Capacity| no|
| Capacitor Capacity| no|
| Capacitor Recharge Rate| no|
| Shield Recharge Rate| no|
| Shield / Armor / Hull HP | no|
| Shield / Armor / Hull resistances | yes|
| Shield Boost / Armor Repair Bonus| yes|
| Sensor Strength| yes|
| ECM Jammer Strength| yes|
| Scan Probe Sensor Strength | no|
| Scan Resolution| yes|
| Targeting Range| yes|
| Signature Radius| yes|
| Velocity| yes|
| Inertia Modifier (Agility) | yes|
| Duration (Cycle Time) Bonuses (Except Weapons)| no|
| Missile Launcher Rate of Fire| yes|
| Missile Damage| yes|
| Missile Explosion Velocity| no|
| Missile Explosion Radius| no|
| Missile Flight Time| yes|
| Missile Velocity| yes|
| Turret Rate of Fire| yes
| Turret Damage Modifier| yes|
| Turret Tracking Speed| yes|
| All Optimal Range (Modules/Turrets) | yes|
| All Falloff (Modules/Turrets)| yes|
| Mining Laser Uield (Including Mining Drone Yield) | no|
| Drone Damage| yes|