Communication Efficiency (CE)

## What is Communication Efficiency

Communication Efficiency, sometimes abbreviated to CE, is the time it takes to reach a province for a government agent travelling from the capital. It represents how difficult it is for the government to exert control over far away provinces. Fast communication lowers unrest and monthly autonomy growth significantly and improving CE is one of the best methods to lower autonomy in the game.

## Communication Efficiency Modifier

Every province in the game has a communication efficiency modifier shown as an icon with either pluses or minuses located in the row of icons of the province view. The actual effects from CE are based on the exact number of days, giving +3.5 unrest and +16% yearly autonomy per 10 days.

There are sixteen levels of communication efficiency modifiers plus a special martial law modifier that shows up in newly acquired provinces. Below is a list of all the modifiers and their average modifier:

### When is the modifier updated?

CE is recalculated with a 6 month interval + a mean time to happen of 6 months, so overall about once per year.

## Travel Time

Communication Efficiency is calculated by measuring the travel time between the capital and the province. Travel time is dependent on terrain, roads, bureaucracy buildings and, for travel across water, trade harbours. See this for a visualization of runners. (Or use the dispatch runners interaction in the estates menu, but that will bloat your save file, making it slower and more error-prone.)

### Land Travel

Each province travelled, including your capital, increases the travel time by an amount depending on the terrain of the province. Select a province and mouse over the terrain to see the travel time and the effect that roads have on it. Below is a list of the travel time across the different terrain types:

 Four days
 Five days
 Six days
 Seven days
 Eight days

### Sea Travel

Communication Efficiency (CE) can move over water quite rapidly in good conditions, but only if there is a trade harbour or natural harbour both in the originating province and the destination. Better trade harbours decrease travel time.

CE over sea zones is calculated using the factor *1 + ((sea zone distance2 ) / 10)*, which rises quadratically the more sea zones must be crossed. This can make long-distance connections across water very expensive in CE terms. Having more ports to act as 'relays'  along the water path will make a significant difference.

### No Connection to the Capital

Provinces that have no connection to the capital whatsoever still get communication efficiency but at a decreased rate, dependent on the distance from the capital.

### Other Effects

Soft cap: CE has a soft cap to limit the effects of high CE values, according to the formula

```

 F
 i
 n
 a
 l
 C
 E
 =
 240
 ÷
 (
 1
 −

 e

 C
 E
 ×
 −
 0.018

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 −
 120

 {\displaystyle Final CE = 240 \div ( 1 - e^{CE \times -0.018} ) - 120}

```

This means that CE will increase slower the closer it gets to 120 Days.

Japanese Shugo: Provinces subject to Shugo power limitation effects have their final CE value increased by 20 days, then decreased by their overlord's (theoretical) CE in those provinces.

New World: Provinces in the North and South America continents, owned by a country whose capital is not in those continents, get their final CE times halved.

## Improving Communication Efficiency

There are three types of buildings that improve communication efficiency: roads, trade harbours and bureaucracy buildings.

### Roads

Roads reduce the travel time of a province depending on the type of terrain. Terrain is divided over three subtypes that determine the effect of roads on their travel time: favourable, challenging and rugged terrain. Below is a list of the division:

 Challenging terrain
 Rugged terrain

Better roads reduce the travel time further. Below is a list of how the different levels of roads reduce travel time on the different kinds of terrain:

 Paved Road Network
 Highway Network
 Road and Railway Network

(\*) except for hills and Tundra who get -3 days.

### Trade harbours

Trade harbours are required for government agents to travel across water (Fishing ports and military harbours have no effect). A trade harbour is needed in the originating province and in the destination. Better trade harbours reduce travel time further. Below is a list of how the different levels of harbour reduce travel time (averaged between the originating province and the destination province):

* Trade Wharf (Rank 1 Trade Harbour): Base travel time.
* Trade Dockland (Rank 2 Trade Harbour) -20% travel time.
* Port's Warehouse (Rank 3 Trade Harbour) -35% travel time.
* Great Port and Lighthouse (Rank 4 Trade Harbour) -50% travel time.

If the trade harbour is located in a natural harbour the travel time is further decreased. Small natural harbours decrease it by 5% while great natural harbours decrease it by 15%.

### Bureaucracy buildings

Bureaucracy buildings reduce travel time across your country. Their effect is dependent on their level. A bureaucracy building in the capital reduces travel time across the whole country while bureaucracy buildings in other provinces (regional capitals) reduce the travel time accumulated in the province itself which then can be used as a new starting point to radiate CE from. For example, a province with a rank 1 regional capital that is 20 days of travel away from the capital would lower that value by 30% and then cut it by another 4 days: 20 - 30% - 4 is 20 - 6 - 4 is 10 days of travel time left. The province thus gets a better CE modifier and then radiates CE out to provinces around it.

Note that bureaucracy buildings do not stack (notable exception being the one in the capital, as it has a different kind of effect). Building a second rank 1 regional capitals right next to an existing one will not result in a meaningful improvement of CE.

Better bureaucracy buildings reduce travel time further. Below is a list of the effects of the different levels of bureaucracy buildings for the capital and for regional capitals:

Bureaucracy building in the capital:

* Rank 1 Capital: -5% travel time for every province.
* Rank 2 Capital: -8% travel time for every province.
* Rank 3 Capital: -12% travel time for every province.
* Rank 4 Capital: -17% travel time for every province.
* Rank 5 Capital: -25% travel time for every province.

Bureaucracy building in a regional capital:

* Rank 1 Capital: -30% accumulated travel time and -4 days of travel time in the province.
* Rank 2 Capital: -45% accumulated travel time and -6 days of travel time in the province.
* Rank 3 to 5 Capital: -60% accumulated travel time and -8 days of travel time in the province.

Version: M&T 2.52.5