Overextension

Negative overextension modifiers

Overextension is a game mechanic modeling the issues caused by rapid expansion.

Each non-core province, with the exception of colonies, causes overextension equal to province development. For example, a province with a development of 24 will add 24% overextension regardless of how big the state is. Note that overextension has no cap; it can potentially go far beyond 100% and its penalties will continue to increase.

Effects

These are the effects at 100% overextension:

	−100%	Trade power abroad
	+50%	Stability cost modifier
	+50%	Mercenary cost
	−2	Diplomatic reputation
	−50%	Improve relations
	+5	National unrest
	+0.5	Yearly corruption
	+0.50	Secretariat faction influence
	+0.50	The guilds influence

In addition, the AI will view overextended countries more negatively, and will be more likely to either declare war itself, or form a coalition against that country.

At over +100% overextension:

• Monthly chance of increasing progress to each uprising is multiplied by more than 3×, growing with higher overextension (though still capped at 75%.)
• Various nasty events will trigger, doing things such as lowering stability or hurting trade. The base frequency is one bad event per year, with the time decreasing with higher overextension. Members of the Holy Roman Empire will be reluctant to support reforms while the Holy Roman Emperor is overextended.

These penalties combined can really destabilize a country. It is advised not to go above 100% overextension as the severity of the risks rises dramatically.

Overextension can be reduced by:

• Coring provinces, which takes time and administrative power
• Selling or granting non-cored provinces to subjects to let the subjects core them (you may be able to annex them later)
• Selling provinces to other nations
• Releasing a vassal that has a core on it
• Making a new client state from the non-cored provinces ( Art of War only)

Note that a country will only accept buying a province if they have a core on the province, or it has the same culture group and religion. They also should not be overextended themselves.

Administrative efficiency

Administrative efficiency directly reduces core creation and diplo-annexation costs. It also reduces the impact of province development on overextension, warscore cost and aggressive expansion, allowing for much larger territories to be conquered at once.

Modifier

Ideas that boost efficiency:

	Traditions	Ideas	Bonuses	Policies
+5%	Deccani traditions	Bharathi idea 6: Brahmin Administration Great Yuan idea 6: Sino-Mongol Administration	—	—

Further modifiers:

	Type
+10%	administrative technology level 17
+10%	administrative technology level 23 (cumulative)
+10%	administrative technology level 27 (cumulative)
+0.4%	Per point of absolutism (max +40%)
+5%	Age of Absolutism splendor ability “Administrative Efficiency”

A custom nation can have a national idea of up to +10% administrative efficiency.

Mission reward modifiers:

	Time	Type
+10%	20 years	Invade China (horde mission tree)
+5%	Permanent	Russian Revolution (Russian mission tree)

Realm

Economy