What is "Diplomatic work"?
About courtier work - effectiveness depends of skill of the courtier (have on mind that courtiers are much more effective on Moral and Loyalty then on Controll).
About police work - effectiveness depends of size of the unit.
Work hours needed to increse Realm Controll and its decay duo to low moral depend of number of peasants in the region.
Number of unites in the region affect on speed of decay of Realm Controll if moral is low.
According to all of it:
- if there is lot of peasants in the region
- if Courtier's skill is low (even if Courtier is good, I am not sure how much he can affect Controll)
- if unites doing Police Work are small
- if there is not enaugh unites doing Police Work
- if there is not enaugh unites in the region
yes, it is possible that Realm Controll stay unchanged after several days working on it.
If region statistics are already low, most effective is to bring enaugh large unites to the region and Arrest Rebels and Hang Rebels.
If region moral is normal, then bring enaugh large unites to the region and do Normal Police Work.
If region moral is high, then bring enaugh large unites to the region and do Normal Police Work and Region Lord or Judge can hold few Harsh Courts (do not let moral to fall too much).
