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

[ferratus]

In a way they already do. The DC system is essentially % / 5, and the DC is increased depending on how vanishingly small the odds are that you can do something.

But it seems to me it would be more intuitive to use percentages to determine the odds that you will succeed at something. For example, that you have a 50% chance to scale a rough wall without scaling tools, while only a 10% chance of scaling a wall made of ice. Or that you have a 70% chance of convincing a gullible child that you are a great hero, but only a 10% chance to persuade the sultan that you are a sheik from the land of Ababwa.

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?

 

[Jeff Wilder]

What are the arguments to using the DC system instead?

A unified mechanic. D&D could have dropped the d20, in favor of d%, but that cow is just too sacred. (Besides, there's already Runequest.) Personally, I'm even annoyed that D&D uses percentiles for things like concealment. I'm really looking forward to putting everything but my d20s away for my upcoming M&M campaign.

 

[nightwyrm]

To the OP, how are you examples any different than if you use d20 instead of d100 (50%=10 or less, 70%=14 or less, 10%=2 or less)? You only want to use d100 over d20 if you want the resolution of your probabilities to go below 5%. How many DMs and players can meaningfully tell the difference between 60% and 62%.

 

[keterys]

The math on d20+X vs. DC Y is actually easier to mess around with than the math on percentile. If you have static math that is unlikely to change much, then percentile is fine though.

 

[jaerdaph]

Because my Call of Cthulhu BRP book stole them.

 

[ferratus]

To the OP, how are you examples any different than if you use d20 instead of d100 (50%=10 or less, 70%=14 or less, 10%=2 or less)? You only want to use d100 over d20 if you want the resolution of your probabilities to go below 5%. How many DMs and players can meaningfully tell the difference between 60% and 62%.

You're right in that I don't particularly care about greater precision over 5%. But it just seems to me to be more meaningful than using the DC system. For example, when you get the weather report, you don't hear that there will be a 15 out of 20 chance of precipitation, you hear that there will be a 75% chance of precipitation. It just seems easier to visualize the odds in percent than in DC.

 

[Remathilis]

Ironically, Palladium uses a d20 for combat/save resolution and a % system for skills (& magic, IIRC). I thought it was brilliant, circa 1997...

Now, it feels like a dice-system cluster-bang.

 

[Scribble]

A unified mechanic. D&D could have dropped the d20, in favor of d%, but that cow is just too sacred. (Besides, there's already Runequest.) Personally, I'm even annoyed that D&D uses percentiles for things like concealment. I'm really looking forward to putting everything but my d20s away for my upcoming M&M campaign.

Eh... I get this way every so often, but it goes away. It's why I can never stay with GURPs too long. After a while of just using d6's I see all my other dice in the pile and start itching to let them have some fun too.

 

[Scribble]

Also it probably has to do with the math as well...

Like you know that your 18 Stat gives you a +4 bonus, and since (just about) everything it might apply to uses a d20 they can just say it's a +4, instead of say a +4 to hit, and a +20% to skills etc...

 

[ferratus]

The math on d20+X vs. DC Y is actually easier to mess around with than the math on percentile. If you have static math that is unlikely to change much, then percentile is fine though.

I don't quite understand, could you elaborate? Is it a matter of smaller numbers being easier to add?