Why do many people prefer roll-high to roll-under?

[aramis erak]

Alternity was a little weird. It was fairly counter-intuitive that a plus modifier made things more difficult. Most roll-under systems add modifiers to the skill value (so if you normally have a skill of 14 on a d20 and you get a +2, you want to roll 16 or lower), but Alternity added its modifier to the die itself. This, together with the degree of success model (roll half your skill or less for a Good success, or 1/4 of your skill or less for an Amazing success) meant that the chances of special rolls were altered much more than the chances of a success itself (if your skill is 14, which is pretty high but not exceptional for a starting character, rolling d20+d6 if you have a +2 modifier does hurt some when it comes to regular success, but it makes it almost impossible to get an Amazing success by rolling 3 or less). In addition, the difficulties scaled a bit weirdly: going from 0 to +/- d4 was pretty chonky, then going to d6 and d8 were fairly small increments, but then it accellerated to d12, d20, and then multiple d20s).

Alternity should, however, be lauded for its absolute dismissal of the d10 as the abomination it is. I don't think it's used anywhere in the whole system.

It seems likely that Alternity served as a testbed for some ideas they had for a third edition (even though it was designed under TSR and not WOTC). Alternity stats were 4-14 though for humans, not 1-20.

Alternity mods didn't add to the die - they changed the die being used. (PM, p 12)

 

[Thomas Shey]

Alternity mods didn't add to the die - they changed the die being used. (PM, p 12)

They were still characterized as adding or subtracting from the die column, however.

 

[Staffan]

Alternity mods didn't add to the die - they changed the die being used. (PM, p 12)

Sure, but something being more difficult was expressed as "+X steps", which meant you moved X steps on the Situation Die Steps Scale:

In other words, rolling at +2 meant you rolled d20+d6, which was a pretty significant penalty.

 

[Fenris-77]

I vastly prefer roll under, but I'll admit it can be harder to wing mods and whatnot. I like that roll under systems, in a d20 environment anyway, account for every stat increase, nit just the ones identified in the class progression. So any stat upgrade is good, not just whatever gets you the next ribbon or whatever.

 

[Thomas Shey]

I vastly prefer roll under, but I'll admit it can be harder to wing mods and whatnot. I like that roll under systems, in a d20 environment anyway, account for every stat increase, nit just the ones identified in the class progression. So any stat upgrade is good, not just whatever gets you the next ribbon or whatever.

I realize you qualified it with "in a D20 environment" but I'm not sure roll-low is any more or less a radical change than just having every stat rather than every other stat be a modifier. The fact most D20 games don't do that is an artifact of how much impact the design at one point decided they wanted them to have, its not intrinsic in the approach.

 

[Fenris-77]

Roll low in a d20 environment allows rolling directly against stats in a useful way, as opposed to abstracting it out one remove to stat bonuses and DCs. It means every stat point counts, which isn't the case for stats in more d20 games. I can't think of a roll high d20 game where every stat point matters in any significant way. Generally speaking this allows the stats themselves to be a more more important cog in the games mechanical chassis.

 

[Thomas Shey]

Roll low in a d20 environment allows rolling directly against stats in a useful way, as opposed to abstracting it out one remove to stat bonuses and DCs. It means every stat point counts, which isn't the case for stats in more d20 games. I can't think of a roll high d20 game where every stat point matters in any significant way. Generally speaking this allows the stats themselves to be a more more important cog in the games mechanical chassis.

I just was saying there's no reason the latter has to be true. There are a number of games built along the line of "Roll Die Size X + Attribute + Skill against target number" as a basic component, and as long as you set the numbers to support that, it could work with D20s too (whether it'd be desirable is a different question and turns on multiple factors, but most of those apply to roll-low too).

 

[Fenris-77]

I just was saying there's no reason the latter has to be true. There are a number of games built along the line of "Roll Die Size X + Attribute + Skill against target number" as a basic component, and as long as you set the numbers to support that, it could work with D20s too (whether it'd be desirable is a different question and turns on multiple factors, but most of those apply to roll-low too).

I think we're talking about different things. Maybe? IDK. Obviously there are lots of games that quite successfully use the base mechanic above (it might be the most common RPG base mechanic). I was very specifically talking about OSR and D&D adjacent games where you have stats from 3 to 18 that can also directly be used as target numbers for rolls when you roll low, with no intervening abstraction or whatnot necessary.

 

[Thomas Shey]

I think we're talking about different things. Maybe? IDK. Obviously there are lots of games that quite successfully use the base mechanic above (it might be the most common RPG base mechanic). I was very specifically talking about OSR and D&D adjacent games where you have stats from 3 to 18 that can also directly be used as target numbers for rolls when you roll low, with no intervening abstraction or whatnot necessary.

All I was asking was what made that any more difficult doing the construct I mentioned with roll high? I mean, if you don't want to use the skill thing directly you could just add the attribute; if you don't want the option of a varied target number, just use a standardized target of 20 and the math's nearly identical.

Roll low's benefit is that its often intuitive, but with a single die and a two digit or smaller number, its not like anyone is going to have an difficulties. If someone is more comfortable with roll high (for the reasons some have expressed) its not meaningfully harder.

 

[Fenris-77]

All I was asking was what made that any more difficult doing the construct I mentioned with roll high? I mean, if you don't want to use the skill thing directly you could just add the attribute; if you don't want the option of a varied target number, just use a standardized target of 20 and the math's nearly identical.

Roll low's benefit is that its often intuitive, but with a single die and a two digit or smaller number, its not like anyone is going to have an difficulties. If someone is more comfortable with roll high (for the reasons some have expressed) its not meaningfully harder.

Ahh, I think I see our boggle. There's nothing wrong with the other construct at all. The d20 roll low is useful for more stripped down games that often have no skill system, or a very abbreviated one. Using the stat as target number provides some nuance those systems don't get elsewhere. It can be faffed with quite a bunch to add detail and modifiers, but that's the basic thrust. A lot of OSR games use that system for exactly that reason (besides the tradition that there's an option rule in B/X to use the stats for skill rolls. You stats essentially represent all your training, not just your attributes, so to speak.

This was never about whether either mechanic was more or less complicated or difficult to use, they just achieve different design goals.