Dice Math!

By cetiken, in Star Wars: Edge of the Empire Beta

So Jay asserted that proficiency dice are only a small bonus over ability dice. I doubted this - after all they are so much more fun to roll. Being bored at work I decided to do some math. Who doesn’t love math?

The goal of this math was to figure out how many success and avdantage symbols each die could be expected to roll. This would show how much of an advantage the proficency die really was.

Ability Die:
Chance of at least one success: 4/8 -> .5
Chance of an additional success: 1 / 8 -> .125
Total chance of success = .5 + .125 = .625 therefore we expect each ability die to generate .625 success on average.

The math is the same for advantage symbols. .625 advantage symbols per ability die rolled.

Proficiency die (we will be counting the triumph symbol as a success):
Chance of at least one success 8/12 = .667
chance of an additional success 2/12 = .167
Total number of success per die = .833

chance of one advantage symbol: 6/12 = .5
chance of an additional symbol: 2/12 = .167
Total number of advantage symbols: .667

Its also worth noting that there is a .083 chance of a triumph symbol. That one is super keen.

My final analysis is that while proficiency dice are definitively better than ability dice the advantage is still to the person who rolls more dice. Conclusion: don’t spend points on skills at chargen.

Yep. Which is why characteristics cost an arm and a leg at character creation.

Though I suppose Trandoshans would have an easier time with that particular price tag…

cetiken said:

My final analysis is that while proficiency dice are definitively better than ability dice the advantage is still to the person who rolls more dice. Conclusion: don’t spend points on skills at chargen.

"Don't spend points on skills at chargen."

This would be true even if skills were more "powerful", mainly because you can't increase attributes with experience, so… it's "best" if you buy a lot of attributes at chargen.

awayputurwpn said:

Yep. Which is why characteristics cost an arm and a leg at character creation.

Though I suppose Trandoshans would have an easier time with that particular price tag…

If I had been drinking coffee, it would have sprayed my monitor when I read this, pure genius!

awayputurwpn said:

Yep. Which is why characteristics cost an arm and a leg at character creation.

Also there is a hard cap of two ranks on skills at chargen. Even if you wanted to be a super skilled guy with average inherit abilities you'd be stuck rolling a max of two dice or your ability and continually outshone by those who boosted their agility.

The biggest tool to prevent this though might be GM rulings that by being untrained in a field, you simply will suffer a greater challenge than if you were trained. Sure, you might be the smartest guy in the room, but you might have more difficulty plotting a hyperspace route without any proper training in astrogation than someone who is less intelligent, but at least well trained.

Being that this is a highly narrative system, I see this as probably the main tool to prevent heavy min-maxing at character creation and notions like "you're being bad at the game if you spend any starting xp on anything other than characteristics."

I'm honestly not sure it needs to be fixed. I think a sidebar clarifying the intent might be useful, but it appears to be working as desired if this post by Jay is any indication. Further I'm not saying that you're bad at the game by spending skill points I'm just observing what the mechanical system is encouraging. There are lots of good reasons to spend points on non-stats. Talents like Stim Application give non-shooty PCs things to do in a fight and force powers are pretty cool if that's your concept. What I am saying its that its better to boost all the thiefy relevant stats to 3 (or 4) than to get max ranks in thiefy skills if you make a thief.

Now for round 2 of dice math. I neglected the poor Boost / Setback die in my last math attack, and it's time to fix that. The Improved Sidestep is a 20 point talent in the Bodyguard and Scoundrel trees. It lets us spend two maneuvers to increase the difficulty of a ranged attack by one. The interesting point is that the unimproved 15 point talent only costs one maneuver and adds one setback die to the ranged attack. Another option for a defensively minded character might be using a weapon with the Defensive quality. That quality takes a maneuver to activate so can stack with Sidestep but not Improved Sidestep. Lets do math to figure out how to make it as hard as possible on our opponents.

Setback die:
Chance of failure: 2 / 6 = .33
Chance of threat: 2 / 6 = .33

Difficulty die (same math as ability die above):
Chance of failure: .625
Chance of threat: .625

Taking the Improved Sidestep maneuvers we can expect .625 fewer success. If we took the Sidestep maneuver and were wielding a vibrosword we could activate its defensive quality and reduce the number of success by .667 instead. This is clearly the better choice if we are trying to not get hit. Especially since the defensive weapon quality adds to your melee defense stat as well as ranged. The drawback of course is that we can’t be defensive with our Gaffi Stick while using a Blaster Rifle or other two handed ranged weapon.

KommissarK said:

The biggest tool to prevent this though might be GM rulings that by being untrained in a field, you simply will suffer a greater challenge than if you were trained. Sure, you might be the smartest guy in the room, but you might have more difficulty plotting a hyperspace route without any proper training in astrogation than someone who is less intelligent, but at least well trained.

After doing some heavy reading with this topic in mind, I have come to the conclusions that what you are proposing would actually break the intended way the system is supposed to work. If you read the text in the specializations area carefully, you can see they use a lot of language like, "this gives him [smuggler] the chance to start with 2 ranks in Pilot(space)." The sentence pretty much implies that they were not expecting you to buy skills at the beginning, but rather just settle with what they give you in your specializations. If you think about it, this works perfectly for organic character development. When the PC's start out, they are new to the Outer Rim, or young, and they are relying on their natural abilities and a little bit of skill to scrape by in a tough part of the sector. As they gain "experience" they also gain skills (funny that) that they can use to improve their natural characteristics, and talents, which are little tricks they pick up along the way. As far as I can tell, spending all your XP on characteristics at the beginning is not only smart, but the way the designers designed the game.

Yes, there are plenty of skills that come from a specialization at chargen. My point though was that there would certainly be some skills the PC doesn't pick up (or removes the need to pick up), by instead boosting only the base characteristic. A slicer (who is going to have a high Intellect) is going to have a decent pool for a Medicine check.

Slicing and Medicine are two extremely different fields of study, and yet, the primary way of being "good" at either of these leads to a character being good at both.

I disagree that increasing test difficulty by one difficulty die, or adding in a setback die for skill checks that are made untrained is necessarily going to break the intended gameplay. Sure, maybe it does go against the spirit of the system, but the intent was that they can do most anything, even if untrained. It doesn't go into how difficult it should be. If anything, adding in difficulty (when untrained) proves the reasoning that training actually has a meaningful effect (as part of this thread goes into proving how minimal the bonus is from the upgrade of an ability die to a proficiency die).

Fell free to disagree and inflict your simulationist ideals on your own players, but we are taking about the beta RAW. Currently a prospective slicer would be better off buying a set of slicer tools with 5 points of obligation than using that obligation to buy rank 1 of computers. Though realistically I expect anyone who calls himself a slicer picked up a rank of computers via initial spec points.

Looking at the system as written lacking tools is a legitimate cause to up the difficulty of specilized skills. IE flying a tie fighter without an o2 mask and control gauntlets is a legitimate time to raise the difficulty. Just because you have never flown anything mor complex than a crop duster is not.

I tend to agree with cetiken, and belive his position is supported well by the movies, where, for example, Luke does rather well flying an X-wing for the first time, dispite having only flown atmsopheric craft (as a hobby) prior to the battle of Yavin. (Could make the same argument for Anikan's podracer-to-starfighter transition) Perhaps even more to the point is Chewie's ability to effectivly operate the an Imperial AT-ST, dispite no familiarity with it's controls or those of a similar vehicles.

That being said, KommissarK is perfectly in the right to bring up his issue. After all that is also part of the point of a public beta, to hear what people do and don't like about the system.

In general, difficulty scale is going to separate the skilled from the unskilled. Not for average to middling difficulty tasks, but once you start to tick up the difficulty dice for an advanced task or the GM starts to put the spiteful hurting on you with challenge dice…having some proficiency dice is going to matter. No need for tables full of penalties or barring characters from attempting a given task because they aren't trained.

Granted you could still succeed based on raw characteristics alone, but your posterior is going to be hanging out a bit further. Especially when you decide that you are going to do some complex field surgery on your bleeding-to-death Twilek buddy using some MacGyver'ed surgical implements, while the thermite bomb wired to your head ticks down from " /_:" (or whatever Aurek Besh numbers look like).

Being able to swing for the fences or pull a hail mary makes things dynamic and fun. Knowing that training is or would have made your chances of success tick up a few notches…is also fun.

Sure Ted you can try a raw Agility 5 test to fall and tumble down that mine shaft and not die on impact. Sandy is probably going to have an easier time of it since she was a dancing girl in her youth and not only has a wicked 5 agility but 3 training in Coordination.

Glad to see someone using expected values to represent relative values of dice. However, you need to be double-check your source distributions, mainly:

cetiken said:

Difficulty die (same math as ability die above):
Chance of failure: .625
Chance of threat: .625

The difficulty die is not a mirror to the ability die. Provided on page 12 of the text, there is only 1 side of a d8 with 1 failure, 1 side with 2 failures, 3 sides with one threat, 1 side with one threat and one failure, and 1 side with 2 threats. One side is blank.

This provides 4 failures and 6 threats on one difficulty die, instead of 5 & 5 on an ability die. The expected values produced by the difficulty die's distribution are:

  • 2(1/8) + 1(2/8) + 0(5/8) = 4/8 = 1/2 failures (i.e. -1/2 success)
  • 2(1/8) + 1(4/8) + 0(3/8) = 6/8 = 3/4 threats (i.e. -3/4 advantage)

Can't find any other numerical issues with your posts, keep up the good work!

-WJL

Thanks for the correction. I had seen a passing reference to ability dice being better than difficulty dice, but hadn't taken the time to rework my analysis. Silly eyes getting all crossed staring at page 222.