Polyhedral Number Based rolling vs. Success/Failure rolling

[Tanuki Tales]

I'm plenty sure there are other forms of conflict resolution and obstacle overcoming in the wide world of table top gaming, but for the purpose of this thread I'm going to concentrate on polyhedral number based rolling (rolling X dice, adding Y modifiers and comparing it to Z difficulty; ala d20 gaming) and success/failure rolling (rolling X amount of dice, adding X amount of dice depending on Y modifiers, Z results are considered Successes and W amount of Successes are required to surmount the challenge; ala games like White Wolf or Burning Wheel).

So, out of curiosity, I wanted to know the playground's opinion to the following questions:

• Which method of play do you enjoy more?
• Which method do you think makes the better game experience for players and/or makes gameplay more efficent/balanced for GMs/DMs/Storytellers/etc. to run?

[obryn]

I like somewhat transparent odds. It allows us to make sure the game designers know what they're doing, and makes the gears somewhat transparent to players.

I have heard, for example, that the White Wolf designers of the 90's had no idea how the relative probability of success changed when you add more dice vs. change the target number. That's pretty unforgivable, but also not too surprising with the insane botch rules in 1e WW games.

-O

[The Rose Dragon]

Between those two, success-based dice pool games. But considering those two are my least favorite dice systems, I don't think it's saying much.

[Jerthanis]

I tend to like number based rolling over Success/Failure, because the concept of Succeeding, but not Succeeding Enough To Succeed is bizarre to me, which is what it feels like when you need a higher number of successes to succeed at a more difficult task. The idea of sliding the number required to turn up a success also doesn't work for me because of the extremeness that builds up very quickly and the backwards feeling mathmatics behind it. For instance, in Oldschool White Wolf games, as the Difficulty of a roll goes up, the influence of your training and talents for generating at least one success goes down, since if it's Difficulty 10, you're equally likely to succeed with a dicepool of 1 as if it were 50. It creates a situation where training and talent doesn't significantly help in extreme situations. In those whitewolf games where 6-10 are a success on mundane difficulty situations, you can get into situations also where two or three stacking minor complications will quickly render a certain roll almost impossible.

Overall, I find totalling the numbers on a die or dice rolled creates a much more versatile and intuitive system. I particularly like Roll and Keep, as the Player has much more to do with setting his or her TN than in many other systems, although I find the exploding dice allow for too much unexpected capability out of amateurs sometimes.

[valadil]

I like success/failure, but from my POV that's pretty much a White Wolf thing. I see it as one of WW's endearing traits and I'm not sure how I'd feel about it elsewhere.

Actually, that's a lie. I've seen it in Shadowrun and I wasn't a fan. The difference was SR was d6 based. There's a huge difference in difficulty between difficulty 4 and 5 and the GM has no wiggle room between them.

I'd like to add one other type of rolling that's kind of in between. Highest die. You roll a handful of dice, but only report on the highest roll. Usually these dice explode (ie, 6 on a d6 is reroll and add). I think this is pretty common and hate seeing it omitted.

[erikun]

It is kind of hard to say, because I like systems with both, and both have their merits. There are good reasons to go with roll + bonus and good reasons to go wiht dice pools. And to further complicate matters, there are systems that look like one, but behave far differently because of how the results are treated.

If I had to pick one, though, I'd go with the dice pool. It's easy enough to have a ton of bonuses with a d20 roll, but not have them feel significant. However, when you're rolling 10+ dice in the same hand, it just feels stronger than when rolling only two or three.

Plus, I've seen games that don't seem to understand the spread of the d20 (or the 3d6, or what have you) and so end up with silly results like the powerhouse losing to the party wimp in feats of strength happening more often than should be reasonable.

I'd like to add one other type of rolling that's kind of in between. Highest die. You roll a handful of dice, but only report on the highest roll. Usually these dice explode (ie, 6 on a d6 is reroll and add). I think this is pretty common and hate seeing it omitted.

Legend of the Five Rings has a roll-keep system. You roll dice pools of d12, and you keep a set number of them (and add them together) for your roll. A dice roll of 5k2, for example, would involve rolling 5d12 and keeping the 2 highest dice for your roll.

[Chugosh]

I have never played roll and keep, but it sounds interesting.

Of the two types of rolls in the o.p., I have to state a marked preference for one to three dice rolled against a known target number, usually that does not waver much. It is pretty neat to throw a dozen d6 down for a challenge, but I think that is better suited to a wargame than to a RPG. Even then it slows down play and makes the game take longer. I like to able to almost at once know if I have made or failed the roll, which has the effect on me (YMMV) of allowing nearly instant narration of the outcome of the roll.

And narration (story or fiction would also apply) is what sets rpg apart from wargame.

[valadil]

It is pretty neat to throw a dozen d6 down for a challenge, but I think that is better suited to a wargame than to a RPG.

This is why I like roll and keep so much. You can still throw a handful of dice, but only the highest one matters. If I throw 20d6 and get five sixes, I can ignore the other 15 dice immediately. It's the best of both worlds - throw a ton of dice, but minimal arithmetic.

[BWR]

Legend of the Five Rings has a roll-keep system. You roll dice pools of d12, and you keep a set number of them (and add them together) for your roll. A dice roll of 5k2, for example, would involve rolling 5d12 and keeping the 2 highest dice for your roll.

d10s, not d12s.

Regarding R&K
The good: you don't get quite the same insane numbers if you had a straight dice pool, making it easier to determine difficulties and what not. People with good dice pools tend to be much better than people with poor pools, more consistently than ones based on a single die roll with modifiers.

The bad: not all mechnical attributes are created equal. Depending on which edition of L5R you play skills (as opposed to Attributes, Strength, Agility, etc.) are either boss or near useless. In general, your Attribute determines how many dice your keep (and roll) while Skills only add rolled dice. Since Attributes are tied to Rings (very important) and are often used by multiple skills, you get far more bang for your buck by increasing Attributes. Skills are cheaper, certainly but for the most part less useful.
Also, you run into weird stuff.
Take Swordmaster the Sword Master. He has the skill Swords at 10 (maximum). You'd think this would make him super awesome. However, Swordmaster only has an Agility of 1 (for whatever reason). This means, in L5R terms, he has a dice pool of 10k1 (roll 10, keep 1, because the maximum you roll is 10, every 2 rolled above 10 is converted to an extra kept die, so 11k1 becomes 10k1).
Take Bouncy McBounce who has an Agility of 8 and no ability with Swords. Bouncy is rolling 8k8 on his attack rolls with swords, weapons he has no training with. He will hit far more reliably than Swordmaster, and his Agility is usable for far more than Swords is.
Sure, depending on which edition you use, skills grant various other nifty bonuses but nothing near making up for the raw power of the attributes. Swordsmaster may have unsurpassed technique but it's mostly useless compared to Bouncy's incredible agility.
This is obviously a rather exaggerated example, but the problem is real.

I don't know of other R&K systems, so I can only go by this one.

[Jay R]

A successful, enjoyable game is one in which the story is so compelling, and the world so self-consistent, that I'm not really thinking about the mechanism for rolling dice.

[Vitruviansquid]

I'm really trying to wrap my head around the mechanical differences between the two types of rolling in this thread...

It seems to me that at the end of the day, both are systems for generating a probability of success or failure, and then the designers of the system will give you tools for manipulating the probability that are as helpful as their balance calculations determine they should be.

I guess I personally like the polyhedral number based rolling because it's more intuitive to me, since I've been familiar with it for a longer time, but that's really more to do with me than anything inherent in the systems.

[NichG]

I sort of like the success/failure system for being more robust to sliding power scales, but it suffers from becoming hard to actually 'do' OOC when you actually make it do so.

What I mean by this is, as the numbers get bigger in D&D the size of the random component of the roll changes with respect to the overall result. So at low levels, you're very swingy, with the d20 roll providing a bigger effect than most numbers you can put into it. At high levels, or in cases where you're highly competent, the random component can be small enough that a given roll becomes a foregone conclusion barring crit failure/success stuff.

E.g. if you have a +4 to hit, the +/-10 from the d20 basically swamps it. If you have a +30 to hit, the +/-10 from the d20 might not actually matter - it becomes more and more common to be in a situation where either you'll hit except on a 1, or you'll need a 20 to hit.

Basically, the random factor shrinks linearly as the numbers go up.

In the success-based system, you have Poisson statistics determining the consequences of 'being very good' at something. So instead of the random factor shrinking linearly, it shrinks like the square root of the mean. This means that you get a much more stable degree of randomness.

An ideal system for me would be one where the random factor is always a fixed percentage of your total modifier, so someone who hits 4 on average would get 4 +/- 1, someone who hits 20 on average would get 20 +/- 5, and someone who hits 200 on average gets 200 +/- 50.

This tends to be clunky to implement with dice though.

[The Rose Dragon]

It seems to me that at the end of the day, both are systems for generating a probability of success or failure, and then the designers of the system will give you tools for manipulating the probability that are as helpful as their balance calculations determine they should be.

You can fiddle with the success-based dice systems a lot more to create a more varied spread of outcomes. But you don't really get more interesting results until you get to set-based dice pool systems or dice pool management systems, which can do more than just success and failure in a single or extended action.

[The Dark Fiddler]

Of the two you listed, I prefer Polyhedral Number Based... I think? Your avoidance of common terms has left me a bit confused as to what you actually mean (the second type of rolling is commonly called a Dice Pool system, by the way).

My favorite system is actually the one used in the Warhammer roleplaying games, a percentile-based roll-under system. You have your stat or skill, rated from 1-100, and try to roll under on a d100/d%. It makes probability ridiculously easy.

[Stubbazubba]

I agree that rolling a single polyhedral die and adding modifiers vs. a target number is more expedient and as soon as the roll can be read the result can be known; that makes for very fast narration, which is a good thing.

On the other hand, I just enjoy rolling dice pools and counting successes. Seriously, when I'm bored sometimes I just pick up 6d6 in each hand and roll them at each other and count up which hand won; the process is inherently fun for some reason, in a way that rolling a d20 or 2d6 and adding modifiers vs. a DC just isn't. But again, it kind of distracts from the narrative, so it has pros and cons.

[Jerthanis]

Basically, the random factor shrinks linearly as the numbers go up.

In the success-based system, you have Poisson statistics determining the consequences of 'being very good' at something. So instead of the random factor shrinking linearly, it shrinks like the square root of the mean. This means that you get a much more stable degree of randomness.

An ideal system for me would be one where the random factor is always a fixed percentage of your total modifier, so someone who hits 4 on average would get 4 +/- 1, someone who hits 20 on average would get 20 +/- 5, and someone who hits 200 on average gets 200 +/- 50.

This tends to be clunky to implement with dice though.

The trouble with Success Totalling mechanics is that it maintains the outliers of 0 and N where N is the maximum number of successes possible on that number of dice.

So essentially, even if you should average 5 successes, it's almost always theoretically possible you'll score 0, and sometimes you might score 15 successes. It's the outliers that you remember and to a certain extent define the feel of a game.

As such, I tend to think of White Wolf games as in general "Powerful people messing up", while I think of D&D heroes as "Flawless Heroes of Legend"

[Komodo]

I've been trying to get into NWOD, but have been having trouble with the dice system. The die pool system really doesn't lend itself well to single, spontaneous actions, because if you're halfway competent at the task, you're going to have enough dice for at least one success (and even in the New World Of Darkness, who set success at 8+, at least one success is very likely with a reasonable pool of four). Extended actions (actions in which you roll multiple times to earn a set number of successes) can work, occasionally, but the problem I have there is that they have systems for actions made to be extended actions that take several in-game hours or days, and there's not drama in rolling for that, because even if you fail you'll just try again until you succeed, and meanwhile aparantly the other players are just standing around picking their noses. Keep in mind, most of my white wolf experience comes from OWOD, but this has been my impression of the New World as I've read through the rules. Please correct me if I'm wrong.

However, I don't hate those success/failure die pool systems as a whole. Anyone ever hear of DON'T REST YOUR HEAD? I never miss a chance to talk about this one. It has one of the best die pool systems I've ever seen. The gist is this: before rolling, the GM tells the players the difficulty, represented by a number of d6's. Any dice rolled 1-3 are successes, and the player's die pool must roll more successes than the GM in order to win the encounter. Every player starts with three dice in a subpool called "Discipline." They also have access to Exhaustion and Madness subpools that they can increase at will. All the successes in these subpools are added together to combat the GM's die pool, called the "Pain" dice.

Here's the catch, though: even dice that don't succeed count. Whichever of these subpools has the highest rolls (usually, this means the most 6's) is counted as the Dominating pool. Good things happen if Discipline dominates, but the Madness pool will drive you crazy, while the Exhaustion pool leads you closer to sleep, which is a Very Bad Thing in this game. So you see, while the players can freely increase their Exhaustion or madness pools, they would be hesitant to do so, as having more dice in those pools makes you more vulnerable.

As for the single-die number-based system, he only advantage that one has is simplicity. It's less exciting because of fewer dice, and it only yields a single number, making it capable of only one thing at a time. I love using this for quick, simple encounters/challenges, but I immediately lose interest if I have to do complex math with the number that comes up. Just tell me what number I need to roll, whether success is above or below it, and lets go. This is why I'm fond of d100 systems like in Warhammer or Call of Cthulhu.

[Jerthanis]

I had meant to respond to this, but forgot:

The bad: not all mechnical attributes are created equal. Depending on which edition of L5R you play skills (as opposed to Attributes, Strength, Agility, etc.) are either boss or near useless. In general, your Attribute determines how many dice your keep (and roll) while Skills only add rolled dice. Since Attributes are tied to Rings (very important) and are often used by multiple skills, you get far more bang for your buck by increasing Attributes. Skills are cheaper, certainly but for the most part less useful.
Also, you run into weird stuff.

While, yes, raising Attributes is generally better than raising skills, and some of the Rings matter a lot, the attributes that make up a ring are often not terribly synergistic for particular characters. For example, Air is made up of Reflexes and Awareness. Reflexes is a combat stat that determines your Armor TN, Initiative and helps Iaijutsu duelists. Awareness is a bit misnamed, being more of a catchall social stat, useful for hardcore Courtiers. A bushi will benefit from Awareness and a courtier will benefit from Reflexes, but they often don't really NEED the other one, and the same is true for many of the other Rings, and so often a character will round out their rings ONLY to get the 10 Insight (progress toward levelling up), or to qualify for a specific Kata.

So as much as Rings matter, they're hard to justify raising as non-Shugenja a lot of the time.

Take Swordmaster the Sword Master. He has the skill Swords at 10 (maximum). You'd think this would make him super awesome. However, Swordmaster only has an Agility of 1 (for whatever reason). This means, in L5R terms, he has a dice pool of 10k1 (roll 10, keep 1, because the maximum you roll is 10, every 2 rolled above 10 is converted to an extra kept die, so 11k1 becomes 10k1).
Take Bouncy McBounce who has an Agility of 8 and no ability with Swords. Bouncy is rolling 8k8 on his attack rolls with swords, weapons he has no training with. He will hit far more reliably than Swordmaster, and his Agility is usable for far more than Swords is.
Sure, depending on which edition you use, skills grant various other nifty bonuses but nothing near making up for the raw power of the attributes. Swordsmaster may have unsurpassed technique but it's mostly useless compared to Bouncy's incredible agility.
This is obviously a rather exaggerated example, but the problem is real.

Well, Swordmaster the Sword Master has spent 54 experience points getting better at swordfighting, and has a... I think 4 point Defect to drop his starting Agility to 1, and Bouncy McBounce has spent 116 experience points getting better at Agility.

Raising Attributes is generally more efficient, you'll usually not want your skills to raise too much higher than the attribute it links to (with the exception of your signature combat style, weapon combat mastery abilities at skill level 7 are game-changing), but raising ONLY attributes is going to wind up leaving you in the dust after getting them up to about 4.

[NichG]

I
Well, Swordmaster the Sword Master has spent 54 experience points getting better at swordfighting, and has a... I think 4 point Defect to drop his starting Agility to 1, and Bouncy McBounce has spent 116 experience points getting better at Agility.

Raising Attributes is generally more efficient, you'll usually not want your skills to raise too much higher than the attribute it links to (with the exception of your signature combat style, weapon combat mastery abilities at skill level 7 are game-changing), but raising ONLY attributes is going to wind up leaving you in the dust after getting them up to about 4.

Another way to fix this aspect of roll and keep is to do something like:

(Higher of skill and attribute, min 1) keep (lower of skill and attribute)

This does mean that there's a particular optimal path to get good in something that requires some figuring (you generally would want to be a few points ahead of your attribute, depending on the relative costs). However it means you can't really neglect one for the other.

You could also just do attributes as the bonus to rolled dice and skill for kept dice, which works nicely in the sense of 'more specific = more important for that specific task, more general = across the board subtle improvement in all rolls'

[Ravens_cry]

On one hand, success counting is significantly more immediate, especially if you use dice that denote the successes in more than numbers. On the other hand, it's trickier for the DM to set a DC that reflects the intended difficulty. Two or more successes do not scale linearly over one. Oh, it's doable, but it's a fairly complex bit of math.

[BWR]

I *snip*.

I'm aware of the details; the varying importance of Rings compared to Attributes, which Attribute is more useful than others and the xp cost and whatnot. The point is that Skills are far less useful than Attributes. It seems really weird that someone with a maxed out skill is not going to benefit from that to the same extent that you would in another dice pool system, e.g. WoD.
When you have to have three rolled dice to be equivalent of one kept die there is something weird. It very quickly gets to the point that you are better off spending all that xp on Attributes and telling the Skills to go hang themselves.
Having a lot of skill should have more mechanical effect than it does compared with raw physical/mental ability.

3e/r fixed this to a certain extent with the introduction of mastery abilities and Raises being limited by Skill Rank or Void, but 4e (which I am not fond of) decided to retard itself on that point.

[Joe the Rat]

Legend of the Five Rings has a roll-keep system. You roll dice pools of d12, and you keep a set number of them (and add them together) for your roll. A dice roll of 5k2, for example, would involve rolling 5d12 and keeping the 2 highest dice for your roll.

I wanted to touch on this because L5R (and WEGs D6 system) are dice pool TN, not Success Count Pools. You roll your dice (maybe only keeping some of them), and add up the total rolled. It does make it possible to assign "impossible" tasks that are beatable only above a certain level of ability. having a 2d10 pool, you cannot make a TN25. If you've got 7d6, and the other guy has 1d6, the guy with 1d6 will always be beat. Success-count systems have a simple way of making something impossible (more successes than you have dice), but rather than simply out of reach (5 successes when most people have a pool of 4), they can be far more difficult to achieve even without a massive pool, and it still leaves the possibility of Mr. 10 Dice Pool crapping out, and Mr. 1 die getting that success. Which is a better approach is a matter of preference.

[Raimun]

Eh.

No real preference if we're talking about the probablities.

Though dice pools can get a bit unwieldy if you're really good at something and have 10-20+ dice to roll.

[Jerthanis]

I'm aware of the details; the varying importance of Rings compared to Attributes, which Attribute is more useful than others and the xp cost and whatnot. The point is that Skills are far less useful than Attributes. It seems really weird that someone with a maxed out skill is not going to benefit from that to the same extent that you would in another dice pool system, e.g. WoD.

Yeah, so? I guess I don't understand why that's such a terrible problem. In R&K, the extreme of spending all your experience points on skills is a less good idea than spending all your experience points on attributes, but it's a better idea still to split your experience points relatively evenly between skills you're interested in using a lot and attributes because raising an attribute is so costly and +1k0 is not such a negligible increase next to +1k1 considering explosions.

I guess I'm just seeing a problem if you go to extremes with it, expecting maxing a skill to be a good idea and it winding up not being a good idea.

I wanted to touch on this because L5R (and WEGs D6 system) are dice pool TN, not Success Count Pools. You roll your dice (maybe only keeping some of them), and add up the total rolled. It does make it possible to assign "impossible" tasks that are beatable only above a certain level of ability. having a 2d10 pool, you cannot make a TN25.

Well, actually, R&K has exploding dice, so when a die turns up 10 you roll again and add to that die's result and more 10s rolled continue to explode, so a 2k2 dicepool can technically make TN 50+ if you're sufficiently lucky. This is actually the thing I consider the most grating about R&K, because it makes combat excessively swingy.

But yes, I brought up R&K as an example of Polyhedral Number Based, and why I liked that over Success Count.