Why don't 3e and 4e use percentile dice for skills?

[Umbran]

Wouldn't it be easier to guess odds on the fly if we used percentages? What are the arguments to using the DC system instead?

As others have said - the DC system unifies the mechanic.

As another note, using D100 gives people the idea that the fine granularity really matters, when I am not of the opinion that it does. Resolution down to within about 5% is good enough for adventure games, I think.

 

[Herschel]

So the decader could keep the d4 company.

 

[Scribble]

So the decader could keep the d4 company.

If that dang 100 sided die would ever stop rolling it MIGHT keep the d4 company...

 

[ggroy]

As another note, using D100 gives people the idea that the fine granularity really matters, when I am not of the opinion that it does. Resolution down to within about 5% is good enough for adventure games, I think.

I would agree in the case of adventure type games where rolls of critical successes and failures are not a major thing.

Cases I can think of offhand where percentile dice systems can have a big difference from d20 is where criticals are a major thing, such as in a superhero type game where there's several different degrees of criticality.

For example, critical successes can be incorporated into low rolls of 1, 2, 3, etc ... while failures are incorporated into high rolls of 100, 99, 98, etc ... where the closer to 1 or 100 the roll is, the more drastic the success or failure is respectively.

Another case could be where critical successes and failures are incorporated into "doubles" rolls of 11, 22, ...., 88, 99, 100. Rolling "doubles" over the "DC" percentage is a critical failure, while rolling "doubles" under the "DC" percentage is a critical success. The likelihood of rolling a critical failure or success is dependent on the "DC" percentage for a success. For example, a "DC" percentage of 85% for success has 3 "doubles" for a critical failure while it has 7 "doubles" for a critical success. A "DC" percentage of 30% for success has 8 "doubles" for a critical failure, while it has 2 "doubles" for a critical success.

 

[MerricB]

Also: Try opposed checks with percentiles.

Cheers!

 

[Chainsaw]

A few posters have commented on moving to all d20 systems.. why the d4,d6,d8,d10,d12 hate? One of the things my crew liked about D&D was the wacky dice... I'm saddened in my current game that half the time all I need is the weapon die and the d20. Eh, we're all different, I guess.

 

[Umbran]

I would agree in the case of adventure type games where rolls of critical successes and failures are not a major thing.

Cases I can think of offhand where percentile dice systems can have a big difference from d20 is where criticals are a major thing, such as in a superhero type game where there's several different degrees of criticality.

For example, critical successes can be incorporated into low rolls of 1, 2, 3, etc ... while failures are incorporated into high rolls of 100, 99, 98, etc ... where the closer to 1 or 100 the roll is, the more drastic the success or failure is respectively.

Well, this rather speaks to what I was talking about.

As a point of game design, do you want to deal with events that happen less frequently than 5% of the time? The difference between 5% and 3% is a whole whopping 2%. Is it worth having multiple dice mechanics to track the occasional 2% difference?

Also, the typical balance implication is that the more rare an event is, the bigger it is when it does happen. Do you really want so much impact from one die roll, even if it is rare?

 

[Elder-Basilisk]

Well, this rather speaks to what I was talking about.

As a point of game design, do you want to deal with events that happen less frequently than 5% of the time? The difference between 5% and 3% is a whole whopping 2%. Is it worth having multiple dice mechanics to track the occasional 2% difference?

Also, the typical balance implication is that the more rare an event is, the bigger it is when it does happen. Do you really want so much impact from one die roll, even if it is rare?

A friend explained this concept to me as follows: let's say you're playing the Empire Strikes back and you're trying to escape from Hoth in the Millenium Falcon. You bust drop down the blaster turret from the bottom of the old rust bucket and start firing. You roll a really really good result. What happens:

d20: Crit! You kill a storm trooper.
d100: 100! You kill the entire storm trooper team trying to set up the e-web.
d1000 with sustain dice: 1000+ max sustain. Wow! You hit a critical structural element and collapse the entire complex (except the hangar you're flying out of) not only killing all the storm troopers in the base but also squashing Darth Vader.

If you don't want to have the potential for that kind of one in a million result, you don't need that much granularity. For his group, the d20 amount of granularity was as much as he wanted to allow to ride on a single die roll.

Here's the other element to this: if the game system includes about the same number of rolls as D&D, modifiers under +5% are worthless and even modifiers as high as 10% are only of marginal value. If 95% of the time, it won't make a difference whether you have that +5% or not, how often do you think it will matter that you get +2% or +1%? Pretty much never. (That's why in 4th edition D&D, while people get excited about a feat that gives +1 to hit, skill focus can give +3 to checks and very few people care. You roll enough attack rolls that the +1 will matter once or twice per session. You generally don't roll enough checks with any particular skill for the +3 to matter even once). In short, the added granularity of a % system is wasted. Unless you make lots and lots of rolls to accomplish all your tasks, it simply won't matter.

 

[ggroy]

As a point of game design, do you want to deal with events that happen less frequently than 5% of the time? The difference between 5% and 3% is a whole whopping 2%. Is it worth having multiple dice mechanics to track the occasional 2% difference?

It would depend on the game. For a generic fantasy style game like D&D, highly rare events with a lot of powerful implications would seem out of place at pre-epic levels. It probably wouldn't make much sense to keep track of such highly rare events, with a probability of less than 5%

Also, the typical balance implication is that the more rare an event is, the bigger it is when it does happen. Do you really want so much impact from one die roll, even if it is rare?

Perhaps for a superhero type game (or beyond superhero) and/or games where huge super rare events can possibly happen, and where balance in the game isn't as big of a priority. Such huge rare events can go all kinds of ways, such as a universe being collapsed from a character temporarily having "Q" (of the continuum) type abilities.

Whether a game should have such huge powerful rare events, in principle should be dictated by the scope of what type of storylines and universes the players + GM are interested in for such a game.

 

[N0Man]

A friend explained this concept to me as follows: let's say you're playing the Empire Strikes back and you're trying to escape from Hoth in the Millenium Falcon. You bust drop down the blaster turret from the bottom of the old rust bucket and start firing. You roll a really really good result. What happens:

d20: Crit! You kill a storm trooper.
d100: 100! You kill the entire storm trooper team trying to set up the e-web.
d1000 with sustain dice: 1000+ max sustain. Wow! You hit a critical structural element and collapse the entire complex (except the hangar you're flying out of) not only killing all the storm troopers in the base but also squashing Darth Vader.

If you don't want to have the potential for that kind of one in a million result, you don't need that much granularity. For his group, the d20 amount of granularity was as much as he wanted to allow to ride on a single die roll.

Here's the other element to this: if the game system includes about the same number of rolls as D&D, modifiers under +5% are worthless and even modifiers as high as 10% are only of marginal value. If 95% of the time, it won't make a difference whether you have that +5% or not, how often do you think it will matter that you get +2% or +1%? Pretty much never. (That's why in 4th edition D&D, while people get excited about a feat that gives +1 to hit, skill focus can give +3 to checks and very few people care. You roll enough attack rolls that the +1 will matter once or twice per session. You generally don't roll enough checks with any particular skill for the +3 to matter even once). In short, the added granularity of a % system is wasted. Unless you make lots and lots of rolls to accomplish all your tasks, it simply won't matter.

In the example of blowing up the complex, that shouldn't just be a random result of the die but something that would be an event (or possibility) planned by the DM, or if the players come up with a very valid plan to do so that the DM decides to go with.

I'm strongly against the notion that some players have (and some DMs allow) of a situation where it's "hey, can I try this crazy remote chance plan?" and the DM says, "Sure, if you roll a natural 20." Having even a 1 in 20 chance to do plot breaking things, instagibbing a solo, or other outrageous things should be less chance than 1 in 20 or it's not really an achievement but just a lucky roll. A single roll should never single-handedly decide the outcome of an entire encounter or quest.

I do want to address the notion that +3 to skills is unimportant in 4E. That really depends on the style of DM. 4E gives tons of examples on how to use skills within combat for disarming traps and devices, avoiding hazards, disabling arcane instruments or portals, or discerning information about your environment or monsters. If you DM is giving you encounters where all you are doing is rolling attacks, then maybe he should try spicing things up a little. I think this style of encounter is where 4E shines, and skills become less useless.