Editing Ogre:CharacterCodex:Introduction (section)

====Skill Modifier vs. DC modifier====
Both modifiers influence your chance of success when using a skill, but there is one important difference between a modifier to a check and to a DC. The DC modifier only affects your chance of success, while a skill modifier also changes your chance of doing a Total Failure. For example, with a -4 penalty to a check, you have more chance of having a check that fall below 0 while a +4 penalty to DC do not increase the probability of having a check below 0. While DC penalty make an action harder to make, a skill modifier also make the action more risky. When giving modifiers, the Gamemaster should always think if the action is only more difficult (DC modifier) or if it is also more dangerous (Skill modifier).