Originally Posted by
peterb
OK. Thanks.
Unfortunately that is not correct. If you have a system where you only have success and failure as the possible outcomes of a dice roll, then it works, but BRP and its ancestor (RuneQuest) and its descendants (Call of Cthulhu, Stormbringer, Ringworld, and so on) all use five different success levels and their target numbers are based on the base target number (the chance to succeed). The target levels and how to calculate them are (from the best level of success to the worst): Critical success, calculated as 5% of the chance to succeed; Special success, calculated as 20% of the chance to succeed; Success, the base chance to success; Failure, a roll above the base target number; and Critical Failure (or Fumble), calculated as 5% of the chance to fail.
An example: A skill check roll for a skill with a skill level of 50 is a Critical Success at a roll between 01 to 03, the roll is a Special Success at a roll between 01 to 10 (but effectively from 04 to 10), the roll is Success if the roll is above 10 and equal to or below 50, the roll is a failure if then dice result is above 50, and the roll is a Critical failure if the roll is above 98 to 100.
If you add 25 to the dice result to make the chance of success smaller the you also make it impossible to get both a critical and a special success, and the chance of a Critical success increases from 3% to 28%. The entire system breaks. The same thing happens at the other end if you substract from the dice roll.
So, you see, applying modifiers to the skill levels is quite important to get the BRP system to work as intended. I've read on another forum and on Twitter that a RuneQuest ruleset is in the making. It's critical that you get modifications to work properly in the product, or else your customers are sure to complain.
For BRP, CoC and RuneQuest I would recommend that the modifier box is changed so that it affects the target number and not the dice result. We still need a way of affecting the dice results because there are, mostly from spells, modifications that affects weapon damage rolls. But they are not as frequent as skill level modifications.
/Peter