How Corruption is Calculated in Rome 2.

Corruption is very poorly articulated in Rome 2, and to the normal player it makes little obvious sense in how it applies to the game. One cannot easily predict its exact course because there is no overt data to judge it by.

For example my Faction Leader's wife has a -5% Corruption Trait. She died and my Corruption level increased from 22.7% to 24%, a 2.3% increase. "Uhhhh??? Do' may no seze..."

This has pissed me off since first playing. So I sat down and worked it out. Actually the way the game creates the Corruption percentage is very simple, it took 30 minutes, if you can penetrate the fog of UI.

First what Corruption is: it is a single universally applied negative percentile figure that affects all your provinces/settlements income equally. For example a corruption figure of -23.4% would lower a provinces' final income/outgoings balance say +2300 golds, by -23.4%, giving you a true net profit in that province of +1864 golds.

The current Corruption percentage is found on the Campaign map by clicking on any of your cities Province/Details tab- its immediately obvious in the income/expenses and marked in red.

Corruption goes up as you play depending upon decisions you make. This comes in various forms.

1. Principally by taking settlements, Corruption increases by 1%. This is the BASE percentage factor.

[All the following others are Base MODIFIER percentiles, not BASE factors themselves. Thus this is where the confusion really arises- there are 2 types of percentages in play here. The Base is a true percentage, the modifiers: a percentage of the Base percentage].

MODIFIER percentiles

2. Character's traits, say a badly judged marriage gives you a buffoon husband with +3% Corruption. Apparently this is a 'real thing' - so my wife tells me...
3. Character's entourage, for example a judge -5% Corruption. [check your judges, one has +5%! When a game stops being a game, and becomes a social commentary I guess...]
4. Technology/Research, various minus Corruptions benefits from the Civil Research Tab.
5. Imperium, this increases as your captured settlement numbers grow, and adds increased Corruption eg 10%
   

To work out the exact corruption is simple mathematics. Here is my current example.

How many captured settlements:..............28........................=..........28% Corruption (BASE)

[captured does not include your original game start settlement/s]

MODIFIERS:

Imperium.........+10%...........................28% x 10%................ =...... +2.8%
General.............-3%............................28% x 3%...................=......-0.84%
General.............-1%............................28% x 1%...................=......-0.28%
General.............-1%............................28% x 1%...................=......-0.28%
'General'............-1%............................28% x 1%...................=......-0.28%
Wife...................-5%............................28% x 5%...................=......-1.40%
Research ........ -15%...........................28% x 15%.................=......-4.2%
TOTAL.............................................................................................23.52%

Game says (in any settlements income/Corruption 'Details')...........23.6%

TAH DAH!!! Eggerzakkerly rightly-ness!

This explains some peculiarities that have been frustrating me for years!

Firstly a general's wife character trait of say minus 3% corruption does not reduce the 'Game says' Corruption from 23.6% by 3% directly to 20.6%. This also shows why the 'Game says' total Corruption figure has a decimal point in it: 21.3%, whereas all the in game corruption bases and modifiers are whole numbers. It's because there is a Base and Modifiers, not merely an arithmetic accumulation/reduction, as it ostensibly appears. Thus when I capture/loot/raze a settlement (all have the exact same effect on the Corruption increase) Corruption goes up 1% Base and with all the modifiers adjusted too. This can be observed by checking any of your settlement Corruption totals before and after conquering a new settlement.

The Generals contribution to Corruption is the same as Statesman status- it applies irrespective. In addition wives modifiers also count. In both cases as personality traits or via retainers. This is also the case for all 'Other Families'- Statesman or otherwise. The 'General' in the calculation is a non family member, and just a statesman.

Hope that explains this incredibly annoyingly opaque subject for those still playing Rome 2.
On reflection, it does kinda make sense in terms of game programme writing, and no better system jumps to mind. What would have been useful is a Corruption Tab that shows the Calculation, but then that starts the precedent for an unending bureaucratic avenue into endless and more pointless tabs, which in a game is even more annoyinger... So, its actually pretty good.

For another similar explanation of Rome 2's 'Family Politics' with the explanation showing precisely how gravitas, influence and Control are calculated- see my other guide here.