Looking at last weeks post, math-oriented folks have probably noticed the diminishing likelihood of failure as die pools increase. Since the absolute worst you can roll is all 1s, once you have 4 dice, you’re guaranteed success. Some people might look at this as a bug and propose an easy fix, like “All 1’s is a fumble”, but I think understanding it requires looking at how the system handles failure.

In this case, I’m against it. Failure, that is.

This is not just a competence-porn issue, it’s part of how things stay fun and interesting. This is not to say failure can’t be interesting – it absolutely can – but it’s rarely interesting all by itself. Failure is interesting because of the complications it introduces into the situation, and I’m all for skipping the middleman and jumping right to the complications. That is to say, if the dice come up short of the target, then it becomes a choice – would the player prefer to fail, or would he like to succeed with some complication or consequence offered by the GM.

This is easy to apply to basic difficulties (4), but how does it apply to higher levels of difficulty. Can a character take on enough consequences to successfully perform brain surgery?

Obviously, that’s pretty nonsensical, so the rule of thumb is that consequences can improve the outcome by a single step, and only if there’s a reasonable narrative for it (the player can male proposals if he likes). Depending on the scope of the activity, the task might be resolved in some way other than the initial skill rolled if that makes sense to the consequence. For example, if you need a computer program(7) but only roll a 5, then you might get a success by:

• Having someone else do it, in return for incurring a substantial (and immediate) debt to them. The program might even be held hostage for you holding up your end.
• You spend all night copy and pasting scripts from websites and you get you program, but your computer is now totally compromised by the various viruses to downloaded in the process.

None of that would help if your goal had been to design a circuit board(13), because that’s a 2 step jump.

Having decided when and how failure happens, it’s important to also talk a little bit about what failure means. Specifically, some thought needs to go into how re-trying works, and what the impact of failure is. In situations where the situation provides clear context for failure then that’s easy, but the situation is not always clear. Looking at the circuit board example, that seems like a task with a very soft failure scenario. If you don’t successfully design the circuit board, then why not just try again?

My thought is that if the task is one where the character can keep rolling til it works, then you’re not rolling to see if ti works, you’re just rolling to see how long it’s going to take. That’s reasonable, but only if time matters in the context of the game, which it often does not. But if everyone’s cool with that being the case, then no problem.

However, some rolls don’t invite that. There are situation where you want failure to stick, in which case failure is a demand for following a different course of action, mechanically handled by trying a different skill or by changing (perhaps improving) the situation enough to merit a re-roll.

With that in mind, the trick will be to communicate clearly to players whether they’re facing a soft or hard failure. In the case of a soft failure, success is inevitable, and the roll is a shorthand for how many rolls its going to take (see the note on duration, above). In the case of a hard failure, there will be consequences of failure, and either the effort cannot be simply re-retried (or if it can, consequences stack).

So, with that in mind we know how to roll, how to judge difficulty and how to handle failure. That covers the basics. Now it’s time to put some spin on it.

Ok, so yesterday we established that we’d be looking at a d6 tally system with a baseline difficulty of 4. We want to expand on that so as to better handle a die pool of up to ~5d6. Given that, there are two different vectors of approach here. The first is the purely mechanical, while the second is conceptual, speaking to the role of numbers. They weave together, so let’s five in from one direction and see what comes of it.

First, we’ll start with numbers. Now, one great thing about d6 systems is that the numbers are pretty well known, and there are decades of games trying to come up with interesting fixes to smooth out the progression of the average roll, since that troublesome 0.5 makes life complicated. These decades are part of why, as I noted yesterday, 4 is such a magical number. And the good news is, there are a few other magical numbers.

The first candidate is 7. 7 is a great number for two reasons. First, it’s the likeliest outcome of a 2d6 roll, and second, it’s the first roll that’s outside of the possible scope of a 1d6 roll. That latter is handy because it provides a fantastic model for something that may not be hugely difficult, but which requires training to be able to accomplish. For example, even if you know how to use a computer (1d6) you don’t necessarily know how to write even a simple program. That requires specific knowledge and training – you’re not just going to “get lucky” if you keep trying. That’s exactly the kind of scenario where a difficulty of 7 is a handy tool.

After that, the next magic number depends on how you look at things. 13 has many of the same benefits of a 7, except that you need at least 3d6 to hope to hit it. The difference is that it’s a bit less likely to succeed – 13 on a 3d6 is harder to hit than a 7 on 2d6. Now, this might suggest a compromise middle step of 10, since that’s a midpoint on 3d6, and it’s +3 from 7 and -3 from 13, and given that 7 is 4+3, and 4 is 1+3 (1 being guaranteed success), there’s some numerical elegance in making the progression 4,7,10,13 (especially because it can be expressed as “base difficulty of 4, with quality of success increasing by one ‘step’ for every extra 3”, something similar to what’s done in a few other dice pool systems).

The problem is there’s some conceptual roughness to it. I mean, yes, I could easily say:
4 – Mundane
7 – Difficult
10 – Complex
13 – Boggling
or something equally pithy and it would still be better than a lot of games (which set their baseline too high) but really it would be utter bullshit. Those terms are crazily subjective, and while I don’t object to the GM interpreting situations, they provide the GM no practical guidelines for how those things are actually set, which would be irresponsible of me.

But if we drop the 10 we get something that’s not quite as intuitive a progression, but is one that gives us a real, concrete basis for the progression: the numbers are such that if you are not at least operating at a certain skill level, you can’t hit them. That means 4,7,13 (and 19, if we really feel it’s necessary).

Now, what those things will mean are going to vary depending a lot upon the specifics of the skills, and when this ends up in a system, some of that is going to have to be offloaded, but the basic progression is pretty simple.
4 – Normal. The difficulty for day to tay tasks that might be difficult, but require only familiarity with the action being accomplished. For example: Disinfect a cut, perform the Heimlich maneuver.
7 – Expert. Difficulty for a task which cannot be accomplished without at least some proper training and experience. For example: Perform more advanced first aid (proper splints & bandages) or give CPR.
13 – Master. Difficulty for a task which requires intense, specialized training. Example: Perform Surgery, prescribe drugs.
19 – Past-master. Perform a hyper-specialized task. For Example: some sort of specialized medicine, like brain surgery or the like.

All of which is to say, the difficulty levels are built on a clear understanding of “Do Not Try This At Home”. If this is something that anyone with a little familiarity could do with luck or hard work, then difficulty is 4.

Now, I should note that I view success as trickling down. If you hit a 7, you also implicitly hit a 4, which may suggest certain bonus or not, depending on the task. If you are doing neurosurgery (19) and roll a 17, then the failure is in the specialized part of the activity. In contrast, if you rolled a 12 (lower than needed for less complex surgery) then the problem was with the surgery as a whole. You get a lot of meaning trickling down through the tiers.

Also, doing this implicitly folds in duration of activity. Climbing a mountain is a task anyone could conceivably accomplish(4). Climbing a mountain in an afternoon probably requires training and experience(7). If you roll to climb the mountain and roll a 6, you still successfully climb the mountain (you beat a 4) but it’s going to take you longer than an afternoon (since you didn’t hit the 7).

Now, this is still just a starting point. We still haven’t added in fiddly bits, and we haven’t subjected it to the real test – a conflict system – but this seems like a solid start.

As I step into creating a die system, lets run through a few things I like and dislike, since these things will obviously impact the final product.

1. I want a reliable/predictable measure of the dice to be rolled. Anyone who has read this blog knows I love Cortex+, but my big complaint with it is that I need to pack _all_ my dice to play. Not because a given roll will use them all, but because I have no useful way to predict which dice I’m going to need in what numbers. This may be a small and petty thing, but there’s a practical underpinning to it.

2. Next, I want to use d6s. There are some practical underpinning to this – they’re ubiquitous and familiar – but it’s also strongly aesthetic. I own lots of cool looking d6s that beg to be used.

3. I want the difference between skill levels (or whatever they end up being) to feel substantial, and I do not need more than 5 or 6 tiers of capability. This is a cinematic/fiction driven sensibility based on the fact that such broad distinctions make for solid character shorthands and are easily recognizable.

Up til #3, all of the options were on the table, but that last step there is going to make a count system problematic. Count systems may have very coarsely grained outcomes (based on number of successes) but the actual die pools tend to progress smoothly, with only moderate differences between pool sizes, especially at high levels. I could work around this limitation with something too-clever, but that seems like a peg-hole problem.

A flat system is still technically in contention, though it would probably require stepped bonuses. For example, my cold was game handles this by making skill bonuses (on a 3d6 roll) +2, +4 and +6. Those are a little close (they work better for Fudge) but the idea of stepped bonuses is not entirely off the table.

The tally system seems like the best contender, something in the Risus/Over The Edge/WEG space, with 5 levels ranging from 1d6 to 5d6 or something similar. Historically I might try starting from a baseline of 2d6 so there’s a “step down” option and there’s at least a little curve in the default roll, but I’m less attached to that idea than I have been in the past.

Now, there’s still nothing concrete to make a decision on, and this can be pretty paralyzing. Almost any choice can be made to work, so what do you do?

Simple: You do -something-. I’m going to go with a tally system because as cognizant as I am of it’s flaws, I’m even more aware of the dangers of sitting here waffling. So with that in mind, let’s see what we can do with a stack of d6s.

The first thing to do is to consider difficulties. I immediately rule out contested rolls because the last thing a tally system needs is more math, so that means fixed difficulties. Since I’m starting from 1d6 I think that means I’m going to pick the classic baseline of 4.

You see 4 show up in a lot of games. It’s a pretty convenient number for a bunch of reasons. On a straight d6 roll, 4+ means a 50% chance of success, and on a 2d6 scale it’s close enough to 75% to be reliable. On a range of die sizes it’s a number that can potentially be hit by a die of any size. All of which is to say that if you’re thinking going with 4 is a ripoff of anything, realize there’s a reason for its ubiquity.

Now, this raises an interesting question: if I’m allowing 5d6 to be rolled, is a base difficulty of 4 even faintly scalable? Certainly, the apex die pools should be reasonably rare, but that’s not any kind of excuse – a known, rare problem is still a problem. Thankfully, I have an instinct that makes this a little less problematic: I’m looking for success to be the expectation. Someone with 1d6 might have some trouble, and 2d6 still has some risk, but by the time you hit 3d6 it’s very nearly a sure thing.

That said, no reason to just leave it at that. Binary success is a little dull because it offers little differentiation between activities. Teaching high school physics ends up on par with crafting the theory of relativity. So that suggests to me that adding additional tiers of difficulty is the best solution.

The problem is that difficulty steps tend to be applied very arbitrary in play. Climbing this hill is this hard, but climbing that hill is that hard and so on. I want them to mean something a little more self-evident. And that, I think, is where I’ll pick it up tomorrow.

Dice systems are, at their heart, kind of dull. This is probably a good thing, since most of the difference between systems can be built upon their framework, so you want them to be simple, reliable and dull. This is on my mind for reasons that are probably a different post, but I’ve been chewing on a core dice mechanic.

Right off the bat you have three big camps of dice mechanic. You have the flat roll, the tally, and the count. Flat roll is most famous in the various incarnations of D&D, which has used it as both roll vs. moving target (old D&D THAC0 tables) or roll + bonus vs target (4e). The “flat” roll may actually have a curve (as in the case of Dragon Age’s 3d6) but it’s always the same dice, and differentiations in skill are represented by changing the target number or changing the bonus. Fudge dice are another weird example of a flat roll that don’t necessarily look it because the range is wacky (-4 to 4) but it’s a fixed set of dice all the same.

Tally systems, such as those used in WEG’s Star Wars or AEG’s Roll & Keep system, are based on totaling up a variable number of dice. Variations in skill can change the size of the die pool, and while there may be some extra mechanical fiddliness in terms of how many dice are counted (as in the Case with Cortex+ or any game with bonus dice) , the core idea is that the pool of dice is the variable and as a subsidiary idea, the size of the dice may also be a variable.

Count systems are usually considered success counting systems, like Storytelling or Burning Wheel. You roll some pool of dice (of variable size, like a tally), but rather than add up the dice, you count the number of results that hit some particular criteria (such as 7+ on a d10, or 4+ on a d6). Left purely in that form, this is just a highly specialized tally system (effectively the dice have some number of 0’s and some number of 1’s) but it’s worth differentiation from the tally because the ways it establishes differentiation can include changing the rules of success counting. For example, successes might usually be on a 7+, but in this particular area in which you excel, they might happen on a 6+. Thus, while the size of the die pool may be one axis, another will often include the means of determining successes.

There’s a lot more fiddly in this. You can add bonuses to a Tally system to make it feel a little more flat-like. In any system, you can add variations in how you measure success and how you handle things like critical successes and failures (all to say nothing of rich rolling). You can get into wacky hybrids or edge cases (like set building), but those three models really cover the bulk of approaches, and they have different strengths and weaknesses.

Flat rolls are the simplest. Even when they require some math, it is usually quite simple, and perhaps more importantly it’s _perceived_ as simple. Reading the die results in a flat roll is easy, with almost no learning curve. Even if the “post-processing” of adding bonuses or the like takes soem effort, it is -after- the roll, a critical point of distinction.

Tally rolls are probably the most robust. If you want to hang a million different mechanics off a roll, or make the die rolling a bit of a game in its own right (like rolling lots of dice, then doing many mini-resolutions from the pool) then this is probably the approach to take, but it absolutely runs the risk of daunting players. Even if you don’t do a lot of fiddly stuff, the perception is that math is hard and slow, and tallying up the dice creates that sense of friction. This can be mitigated with small or familiar dice pools, but it’s always the specter over the system.

Counts are something of a compromise. They offer much of the same mechanical robustness of Tallies, but they promise greater simplicity than doing math, and in my mind they deliver on that, at least to an extent. There can be a little bit more of a curve in picking up a count game, but the act of reading the dice is an educational one, and most people get much faster at it with only a little practice. Unfortunately, there are some problems that come with that. First, that simplicity is based on the method of counting remaining the same, and if the system leans on changes to that, it slows things down. Also, you can only rely on the simplicity scaling so far – if the dice pools get huge (like, Exalted huge) then it will still bog down.

All three methods can work very well. Even more, all three are robust enough that if there’s some particular element you want to accentuate or avoid then you can easily tweak them to that end.

I’m dwelling on this because I have a dice system in mind for a project, and i want to step back and consider its weaknesses and strengths before I totally buy into it. More on that tomorrow.