Die roll modifier
A die roll modifier (DRM) is a small integer, used to increase or decrease a "roll" of a virtual ten-sided "die". Virtual dice are used to randomize the results of several processes in EU2: combat (land, naval, and assaults) and sieges. In all cases, factors that tend to favor a side give a positive DRM to it, or sometimes a negative to the enemy. Unfavorable factors give a negative DRM or a positive DRM to the enemy.