There's been an awful lot of discussion about the fifth edition (officially fifth, that is, since opinions vary as to what has constituted a new edition over the years) of Dungeons & Dragons, much of it quite positive. I can only see this as a good thing, since D&D remains pretty much the only RPG non-gamers can name and I think that we all benefit from the brand staying healthy. Even though I still prefer the earlier versions of the game, primarily the "basic" editions, I've been talked into playing through the 5e adventure from the starter set; it's not bad, although certainly not enough to make me buy 5e.
One thing has really stood out for me, however: the Advantage / Disadvantage mechanic. For those unfamiliar with it, when your character has the advantage you roll 2d20 instead of 1d20 and take the higher (i.e. more favourable) result. Likewise, when you are at a disadvantage you roll the 2d20 and take the lower, least favourable result. It's not the first time I've seen something along those lines, but something about the implementation has really clicked for me. Perhaps it's the terminology, since it's so easy as a GM to say, "Sure, you definitely have the advantage here," or "Unlike the Northmen you aren't wearing cleats as you fight on the frozen lake, so that puts you at a disadvantage." No tricky mechanics to deal with, either, just a very simple way to make a good result more likely - but not guaranteed!
I'm finding it far more interesting than the old +2 bonus sort of thing, even though my legendarily poor dice rolling means I still fail much of the time. In many games I've used rather broad skill systems by looking at a character's background and profession and judging what seems likely instead of having detailed lists of abilities, and I can certainly see this fitting that approach. Grew up in a port town, helping your uncle on his trawler? Sounds like you should have an advantage when securing that rope, then. Easy.
Looking at Fudge the obvious way to try something similar is probably to have the player roll 5dF instead of the normal 4dF and total the four best or worse results. Has this been used in a Fudge game elsewhere? Nothing comes to mind, although I admit I've yet to check. I'd be interested to see what people think of the idea in general and whether there's a better way to do it.
‘If a man does not make new acquaintance as he advances through life, he will soon find himself left alone.
A man, Sir, should keep his friendship in constant repair.’
- Samuel Johnson
This is pretty well established, actually. Fudge Factor had a few implementations (back before it went offline), and an old list had one as well. Off the top of my head:
1) Partial Levels: You get 1 additional die, which is clearly marked in some way (a different color, generally). If you have an edge, you only count positive results on that die. If you have a disadvantage, you only count negative results on that die. On average, it adds 1/3 or subtracts 1/3.
2) Partial Levels 2: You get 1 additional die, which is not marked. Take the best 4 out of 5 or the worst 4 out of 5. This is roughly 0.8 either way.
3) Dice Pool: At Fair, you get 4 dice. Each level away from Fair adds 1 die. Roll all the dice, and take the best 4 if above Fair or the worst 4 if below Fair. This opens up the entire Abysmal-Legendary range to all characters, but it also makes each level add less. Legendary is roughly equivalent to +2.25 instead of +4.
The math on Advantage-Disadvantage works out to being roughly equivalent to +2 on a d20 if you need a 10 or so to succeed, but it's closer to +5 around the extremes, because of how it curves the roll. Fudge already has a curved roll, so I'd be inclined to skew it pretty simply, using 5 dice instead of 4. However, that does create a situation with a lot of dice in play, and that's pretty close to a +1 anyways in how it handles. A fix here would be to use 3 dice as a base instead of 4, which also lessens the impact somewhat.
An alternate method would be closer to the first partial levels system above. While D&D 5e has only one Advantage or Disadvantage, Fudge could easily have more, simply by virtue of having multiple dice. Starting with 3 and adding up to 3 more would handle things fairly well, while also avoiding some of the weirdness with only one Advantage or Disadvantage (the whole matter of "long range and windy" is the really obvious case where two would come up fairly often). You could also have a more active system, wherein you can reroll the dice you already have, and each Advantage or Disadvantage allows/forces one reroll. This does have the oddity of a spread of 2 if going from plus to minus or vice versa, but if you only allow/force rerolls of plus or minus and just take the die away if it doesn't return its previous result, you're good. This also takes some of the sting out of multiple advantage or disadvantage, as you would need to roll +/- 3 or 4 for 3 to apply. This also replicates the effect of extremes being disproportionately effected, which is a nice side benefit.
I'd recommend the last method, personally.
The [-] die.