D&D 5E Advantage vs. re-rolls

[Yunru]

This is the conclusion I ended up with.



Woops! Apparently [MENTION=12731]CapnZapp[/MENTION] was reading my mind, because a limited resource was intended. I guess I made the subconscious assumption that since pretty much all re-rolls in 5e are limited resources re-roll implies limited resource.

The best example of what I was wondering about might be the fighter's Indomitable (limited uses, reroll only a known failure). I believe we've worked out that while the value on any particular roll is the same as advantage, the overall value is twice that of advantage do to not needing to use it half the time. I ended up verifying it with a table.

That assumes an equally limited resource nature to both. Without either resource being limited, rerolling is almost always strictly inferior. Accounting for Advantage's nearly always infinite nature (in almost all cases you have it for a duration, not a number of uses), rerolling becomes even worse.

 

[CapnZapp]

That assumes an equally limited resource nature to both. Without either resource being limited, rerolling is almost always strictly inferior. Accounting for Advantage's nearly always infinite nature (in almost all cases you have it for a duration, not a number of uses), rerolling becomes even worse.

Now you're starting to compare apples to oranges in your quest to make rerolls look bad.

Facts: at 50% chance, the actual mechanic - advantage or reroll - is equal.

If you have a charge of each, such as with Inspiration or several class features, reroll has a 50% chance of not needing you to spend the charge.

But of course, if you feel it is useful to tell us obvious things, such as unlimited advantage is better than limited rerolls, hey I can't stop you. Not sure anyone's going to be overly impressed, though...

Sent from my C6603 using EN World mobile app

 

[Yunru]

Facts: at 50% chance, the actual mechanic - advantage or reroll - is equal.

Mathmatically wrong (due to the two tiers of success for attack rolls - hits and crits) and factually incorrect.

Advantage lets you take the higher of two rolls - you always get the highest.
Re-roll forces you to take either the first or second roll with no prior knowledge as to what both will be.

State whatever percentage you want (except 5%), that holds true.

And no, I wasn't comparing apples to oranges, I was stating that they are apples to oranges, and that any comparisons made thus far are trying to make them the same.

 

[Nagol]

Mathmatically wrong (due to the two tiers of success for attack rolls - hits and crits) and factually incorrect.

Advantage lets you take the higher of two rolls - you always get the highest.
Re-roll forces you to take either the first or second roll with no prior knowledge as to what both will be.

State whatever percentage you want (except 5%), that holds true.

And no, I wasn't comparing apples to oranges, I was stating that they are apples to oranges, and that any comparisons made thus far are trying to make them the same.

You do have prior knowledge of the first roll when you make your decision to reroll. A reroll without any prior knowledge is just a roll. "The first roll won't count. The second roll will."

Reroll equals advantage when the outcome is strictly pass/fail and the outcome of the first roll is disclosed before the reroll declaration is made. Rerolling becomes worse than advantage when those constraints are changed. Attacking changes the strict pass/fail constraint so a reroll is worse on its face.

If a designer is working on a mechanic to give out a few times a day, reroll feels nicer in that it won't be "wasted" the way advantage can be (both rolls succeed) even though the effect over a large set of roll is the same change in probability, and as pointed out earlier in the thread, reroll can stack with advantage.