What are advantage and disadvantage in BG3, and how do you get them?
One thing to note is that advantage or disadvantage on a passive check (that is, a check you wouldn’t roll for) are conveyed through a +5 or -5 respectively. For example, if your passive perception score is normally 13, with disadvantage from dim lighting it would be an 8. A hidden enemy would only need to roll an 8 or above on their stealth roll to avoid notice.
The article doesn’t get into the math of how much of an equivalent bonus/penalty that Advantage/Disadvantage gives, and that is the actual complicated part of the mechanic.
On average the bonus or penalty equates to about +/- 3 on a roll. However, it can swing higher or lower depending on the difficulty of the check compared to the character’s inherent modifiers. If a character can only pass by rolling a 20 (or can only fail by rolling a 1) after their other modifiers are accounted for, then the effective bonus/penalty is only +/- 1. Conversely, if the necessary roll is 11 or above to pass (or 10 or below to fail) then it is +/- 5.
The reason Advantage/Disadvantage feels so powerful is because D&D is balanced around players needing to roll somewhere between 7 and 14 to be successful in most of their actions, and that is the range at which Advantage and Disadvantage are most impactful.
I thought Advantage/Disadvantage was so powerful/hurtful because you roll 2 dices and take the better or worse roll.
Disadvantage: Your character rolls twice and takes the lower of the two results.
Advantage: Your character rolls twice and takes the higher of the two results.
That is what is done, but they’re attempting to explain how that actually effects the odds. If you only had a 5% chance to succeed to begin with, advantage only bumps that up to about 10%. On the other hand, if you were at about a 50% to succeed, you jump up to a 75% chance with advantage. Bounded accuracy means that most rolls are balanced to have somewhere between a 30-70% chance to succeed; right in the range where advantage is most impactful.
I dropped my statistics class, but I remember the teacher to this day because of the story he told us.
He said he came from India to the US and he didn’t eat meat. He went to a restaurant and ordered a hamburger without the meat–just bun and lettuce, tomato, etc. They said sure. He then asked if it was be cheaper because the meat was the most expensive part of the burger. They said that they had to charge him extra for a special order.
Anyway, here is your upvote for your math. Thanks!
