Modified Rule of Six, ...and "always having a shot" Options

[GunnerJ]

I've tried, since SR4 was announced, to stay current on all the important discussions, but alas, I have recently fallen behind. So, if an idea like what I am about to suggest has already been brought up, my apologies.

Some people seem worried that the new system will remove the possibility that existed in SR3 to always be theoretically able to succeed, no matter how hard the task. This is because the Rule of Six made it so that no matter how high the TN was, there was a theoretical chance that at least a single die could hit it. With the new system, it is feared, this will go away. If you need at least X successes against a TN of 5 and you have less than X dice to roll, tough luck.

I don't think it necessarily has to be this way. The "always have a shot" feel of SR3 can be maintained in SR4 with a simple reworking of the Rule of Six. Basically, if you get a 6 on a die roll, not only do you have a success, you can roll that die again. This process does not terminate, so if you roll a 6 again, you get another success and another re-roll. If, on a re-roll, you fail, then you stop and have as many successes as the roll generated so far. Same with a 5 on a re-roll, except you get another success before stopping.

In this way, even a single D6 has a theoretical chance of generating any number of successes. It seems a very basic idea, so I'd bet someone else has thought of it; so again, sorry if this is redundant. But I figure this idea is worth a(nother) mention, at least for a potential house rule.

[Ellery]

It has been mentioned in several places, and I think it's a very good idea. It's especially nice that it's occurring to a number of different people. It has nice statistical properties, too--smoothing out probabilities so you don't jump from an action being only "kind of hard" to "utterly impossible" when the number of successes needed goes up by one or a one-die penalty is applied or someone with one lower skill tries the same task.

[Austere Emancipa...]

Yep, at least by mfb, Eyeless Blond and me, and probably quite a few others as well, in several threads. It's easy to miss these things, though, because there's dozens of rather long threads in which everything about SR4 is discussed. And yeah, as more and more people are coming up with this themselves, I'm starting to think this would be a very good idea -- so much so that I really, really hope the developers haven't decided on a different method of getting rid of impossible tests yet (unless this different method is absolutely brilliant and nobody here has yet come up with it).

This post has been edited by Austere Emancipator: Apr 7 2005, 06:28 PM

[Penta]

Every method is fucking brilliant until it meets reality.

Yes, I'm bitter, cynical, and dissatisfied with life.

Ergo, I play RPGs.

[Eyeless Blond]

Honestly I don't know how it could work any differently. If the vast majority of tests have a Threshold, then rolling 1 or 2 dice would mean you have no chance of actually pulling off most tasks under such a mechanic without such a method of (possibly) netting more than one success per die.

I really think it'd be a great mechanic to add to such a system; in fact it's one I'd like to add to the current SR system for Success and Opposed Tests. Each die roll nets an extra success each time you beat the TN by 6. One of the things I think is odd about the current system is how you're limited in successes by the number of dice you roll; this would go toward changing that.

[Austere Emancipa...]

[Synner]

Eyeless - The Aeonverse version of the nWoD rules actually had a variant on that which restricted it further but I can't for the life of me remember how it worked (have to dig out the books) - so my point? There are other ways of handling it.

[Kagetenshi]

I personally think it's a very bad idea, as it seems to open up a magnitude of success that isn't reasonable (as opposed to the current exploding-dice method, in which a success is still a single success even if the TN is 24 and the roll was a 61).

~J

[GunnerJ]

Just to give a bit more substance, I went and modified my SR4 success calculator to show what would happen with the Rule of Six I outlined.

Here is a sample of the old results, which doesn't use the new Rule of Six:

[Kagetenshi]

Out of interest, why do you sample rolls? It seems to me it would be better (both to avoid statistical anomalies and to avoid any weaknesses in your RNG) to just calculate the theoretical expected successes. There are visible anomalies creeping in there all over the place (look at expectation for one die sans NRo6, for instance; you've been rolling high).

~J

[GunnerJ]

The results that I feel are most important to compare are for 6 dice and 12 dice. 6 dice represents SR4's average ability, and the successes on a 6D6 roll represent what an average man on the street with intermediate training can pull off. 12 represents the most exceptional ability in SR4 from chargen and without enhancements from areas other than attributes and skills. The successes from a 12D6 roll represent what an exceptional individual with expert training can accomplish. I contend a Shadowrunner will roll dice closer to 12 than to 6 in most cases, but for establishing a global norm, 6 dice results are important.

[GunnerJ]

[Kagetenshi]

You just noted it yourself, it's off by over three millionths. You're not, paradoxically, going to get closer to actually rolling the dice by actually rolling the dice, at least not while your dierolling doesn't approach infinity.

~J

[GunnerJ]

Um... so?

[Kagetenshi]

So it's wrong, and for at least that portion it's easily corrected. I'll see if I can figure the formula for the with-reroll side; it shouldn't be difficult, once I get some caffeine in me.

Actually, I think what bugs me isn't that it's wrong, but that it was far more work to do what you did than to get the precise value. I'm really not sure what the point of it was.

~J

[GunnerJ]

Look, I'm doing this for fun, because I want to make guesstimates about a P&P RPG. I'm not building a bridge here. Lives aren't on the line. Is there some reason why we need accuracy to the millionth degree?

[Kagetenshi]

As my ninja-edit states, the part that gets to me is that it was extra work for reduced accuracy.

~J

[GunnerJ]

[Kagetenshi]

Fair enough.

Incidentally, unless I messed up my math, you should expect exactly .4 successes per die with exploding sixes (which jibes with your findings).

So what about 6 and 12 dice are we looking at? We've got 2.4 and 4.8 successes, so that suggests that any 3+ Threshhold test is fairly hard, any 5+ very difficult indeed. Doesn't seem like a lot of modifier wiggle-room for Threshold…

~J

[GunnerJ]

[Kagetenshi]

I see that you consider them important, but I'm not seeing what about them we're discussing. They've got an expected number of successes. Are we debating whether they should have more? Less?

~J

[GunnerJ]

Er, see my latest edit. I was deciding how I wanted to phrase what I said.

[Kagetenshi]

I pity anyone who has to read this after all of the edits :)

I think it's a better solution than doing nothing, certainly, but I'm up in the air as to whether or not I like it as a solution in general. I'll have to run some numbers.

~J

[GunnerJ]

[Kagetenshi]

It's true, but providing that extra successes still mean a better overall quality of success, it provides a chance for a better lucky shot, as far as I can tell. I'm going to have to spend some time with Mathematica before I rightly figure out whether or not I care, though.

~J