Earlier this week, the subject of opposed stat checks came to mind. Although it seems to be the sort of subject that would have been done to death several times over, I found that I had a couple of what I hope are original thoughts on the subject – and a couple of advanced versions of techniques that we all have to develop as GMs. So this occasional series is going to look at the whole panoply of Stat Vs Stat questions.
As GMs, we are used to having to interpret stats into personality attributes all the time, and vice versa. This character should have a DEX of what? This other character has an INT of 13 – what does that mean?
Most analyses work in reference to the ‘average person’, but this is not the only basis of comparison. And that’s what today’s article is all about – looking at the ground rules.
Most game systems have a particular set of ubiquitous stats at their heart. Some may split one of them up into two sub-stats, others may roll a couple of them together into a broader umbrella, but the concepts embodied by these stats are so fundamental that almost every game system has them, or some equivalent. All told, there are six of these stats.
The six core stats that form the bedrock of most game systems, one way or another, are the stats inherited from D&D and other early RPGs. They are:
- WISdom, and
Like a strawberry birthmark, the DNA of modern games systems continues to reflect their descent from these early prototypes.
Stat Vs Stat
While most interactions in RPGs come down to attack vs. defense, or skill vs. target, or skill vs skill, there are still occasions when the interaction is more primal, and require a test of raw capacity. When that test is opposed by another type of capacity, the result is a stat vs stat contest.
The Six by Six Matrix
With six stats, each of which can be opposed by any other, including someone else’s capacity in the same measure, the number of combinations can be expressed as a six-by-six matrix, where each column and each row belongs to each of the core stats. That gives a total of 36 possible specific types of stat vs. stat check.
Some of these can be unusual, so rare that they virtually never occur in real life. Some are frequent and common. So the interactions themselves have differing value to a GM. And its entirely possible, even likely, that not all of the possible applications of each combination will have occurred to any given GM.
Nor can I promise to cover the whole field of possibilities, for the same reason. But a systematic approach gives me a better shot at it than blind chance, because it forces me to think about those unusual modes of interaction. Until I adopted this approach, for example, I had never thought of a circumstance in which a CHA vs DEX check might be needed. Now a couple of them have occurred to me – which means that my repertoire of techniques has grown, and this series has already made me a better GM.
Stat checks in D&D / Pathfinder
Since these core stats derive from D&D, and each game system defines these stats perhaps just a little differently, I have decided to use D&D as the framework for the comparison. But the results will be just as applicable to game systems as Diverse as Traveler, Call Of Cthulhu, Champions, Indiana Jones, and Dr Who.
It must be stated up-front that there is no official mechanism for making opposed stat checks in the 3.x / Pathfinder game systems (never mind stat vs stat checks!) They attempt to cover this situation by giving characters an untrained skill check and making all contests either attacks or Skill vs Skill contests. But what do you do when there’s no skill that specifically covers what the player is trying to accomplish? What if what you are attempting is to use a skill untrained that doesn’t permit untrained use?
Champions uses the example of a character being pushed out a window and trying to grab the window ledge before she can fall. In D&D/Pathfinder, a GM might employ a Reflex Save for this purpose, so it’s not the perfect example. How about trying to walk across rice paper without leaving a mark or tearing it? That’s not a “dodge” sort of activity, so it’s not appropriate territory for a reflex save. The best way of resolving the question is with a DEX check against a target nominated by the DM.
There are times, then, when stat checks are a useful extension to the GMs toolkit, canonical or not.
Mechanics of Opposed Stat Checks
There will be times when a character is trying to do something and another character is trying to stop them from succeeding. When there’s a skill covering both activities, you get a skill vs skill check.
As soon as you acknowledge the utility of the occasional stat check, you run into more ways for them to interact with the game system: Skill check vs. Stat check, and Stat check vs. Stat Check. The first gives us a guide apon which to base the game mechanics – it should be parallel to the skill check system. In effect, what we’re talking about is a roll of d20 + Stat Modifier or (in some game systems) 3d6 + stat modifier. This means that a character relying on raw potential instead of expertise is always at a disadvantage relative to a character who can bring some skill to bear.
In a game system that doesn’t give stat modifiers, like the Hero System, you can use the stat itself. Or you can have each character make a stat check and compare who succeeded by the greater amount.
Other systems are possible – I have seen AD&D systems in which you were awarded 1d6 for every 5 points of a stat, for example, and the highest total won. I have seen that same approach employed in Traveler.
A useful way of looking at the situation is this: One character is attempting to do something, and the opposing character is using his stats and expertise to set the target required for success in overcoming his resistance.
I had done a whole lot of very pretty graphs to examine the way the chances of success shifted in opposed skill checks, like the one below:
The graph was generated using AnyDice and then colored.
Unfortunately, for some reason, I suffered a complete brain meltdown and completely forgot that D&D 3.x and Pathfinder use a d20 instead of 3d6. So these are pretty much useless, and the article is a LOT shorter because I had all sorts of variations to discuss. Oh, well.
Ties: Success, Failure, or something in between?
Is the goal to beat the target, or to match the target? How you choose to handle ties is generally up to each GM, possibly drawing on the skill vs skill rules for consistency. As a general rule of thumb, I usually assume that matching the target or better is enough for success, but you’re free to choose an alternative interpretation.
Two Modes Of Interaction
There are two modes of stat interaction that can result in a Stat vs Stat check: External and Internal.
This is where two characters are opposing each other. An Arm wrestle, or discus throw, or whatever.
This is where the character is opposing himself. A good example might be trying to do some delicate task (threading a needle) while extremely seasick (DEX vs CON) – if the DEX check succeeds, he has threaded the needle; if the CON total is higher, then the character is too distracted by the need to keep his lunch down. There will be many more, and better; I wouldn’t actually run this as Stat Vs stat, but as two separate stat checks – with the margin of success in the CON check becoming a bonus modifier to the CON check. That way, the character can actually lose his lunch on a failed CON check.
Not all Combinations Are Relevant
So, we have six stats, each of which has some form of stat check, which can interact with any of the six stat checks in one of two ways. That’s 72 combinations, at least in theory. No matter how interested you are in the subject, though, by the end of 72 combinations you would be pretty burned out on the subject – that list of combinations needs to get pruned down to something more manageable.
Fortunately, not all combinations are going to be relevant. STR vs STR, for example: there’s not much need for an Internal Mode with that interaction, but there’s definite value in an External Mode. That probably halves the number of interactions to be detailed. In some cases, both will need to be considered, but at least some of the time, only one mode will matter. I figure that’s a 33% reduction.
Then there’s the fact that almost half the entries on the original table are going to be redundant. STR vs. CON is going to be the same as CON vs STR – or close enough that they can usually both be discussed under the same heading. That’s about a 40% reduction.
All told, that’s 67% x 60% x 72, or about 29 interaction modes to consider.
The shifting perspective
External mode implies that one stat check will belong to a PC and one to an NPC. But the interaction remains the same, regardless of which character is trying to overcome the other’s resistance, so generalizing instead of saying which belongs to the PC prevents replenishment of the combinations matrix by adding a new variable.
About the Stat Vs Stat series
All told, there will be nine parts to this series, which will be an occasional item here at Campaign Mastery.
- Part 1 is this introduction.
- Parts 2 to 7 will each focus on a single core stat, and the combinations with that stat’s check.
- Part 8 will create a new characterization tool, the Matrix, based on the interactions described, and show how to use it to turn stats into characters.
- Finally, Part 9 (all going well) will turn that process on its head and demonstrate a way to use the matrix to turn a personality into stats.
Right, so that’s got the decks cleared. Originally, I was simply going to dive straight into the interactions, but as the article began to take shape I kept finding more things that needed to be addressed in a preamble – until it reached the point of needing to be an article in its own right, which became this article. Next Time: Strength. Because I want to hit the ground running with the series – and because I haven’t actually gotten to the part I originally intended to write – I’m aiming to present part two next week. Let’s get down to business!
- Stat Vs Stat Part One: Introduction – The Basis and Methods of comparison
- Stat Vs Stat Part Two: Strength Vs. Stat