Scaling in RPGs

[Nom]

On interesting factor that many game designers forget to consider is scaling. Scaling asks the question: When we move outside 'standard' parameters, does the system still work?

Many systems are locked around 'normal human' parameters. When scores start moving outside these parameters, everything goes wacko.

An easy to understand example:

The RuneQuest system (which IMO is a very playable simulation system) has ability scores which for a normal human lie in a 3-18 range (yes, 3d6). Ability scores can be trained by spending a number of training hours equal to the current score * 25.

This works generally OK for a normal human.

Now consider a troll (strength say 15-30) and a pixie (strength 2-8) {note: numbers demonstration only, and may note correspond to known monsters}. For a pixie, training from strength 5 to strength 6 represents a massive increase (% wise), and yet takes only 125 hours. Meanwhile, for a troll to go from 22 to 23 (a moderate increase for a troll) takes 450 hours.

Scaling can often become a problem in ability vs ability contests, where abilities become very high or very low. If I successfully hit 98% of the time and you successfully block 98% of the time, the contest tends to degenerate. Similarly if we both have scores in the <10% range. There are various mechanisms for doing contests to overcome this, but that's another discussion.

And what if my 98% to-hit mortal fights a demi-god? How do I adjust the scores to sensibly model the battle? What if two demi-gods fight?

In general, any system that uses bounded absolute values will be susceptible to scaling problems.

Sometimes, scaling is a problem at one end only. The Hero Wars (http://www.glorantha.com/) system uses a mastery concept, where each mastery level is basically an order of magnitude better than the previous. In a contests, masteries are first cancelled against each other, and then an advantage is given to whoever has the higher remaining. The mechanics of two apprentice swordsmen fighting are substantially identical as to when two demi-gods duel. Moreover, we can meaningfully express a demi-god vs an apprentice in the same system.

There is still a scaling problem with really low scores, but the upper end scales nicely. Addmittedly, Hero Wars is more cinematic / storytelling than simulation, which offers an immediate complexity advantage.

[ShannonA]

Nom,

Your examples are dead-on. Creating a more scalable system was precisely one of the goals in developing _Hero Wars_, and I think it came out pretty well. It's core idea was to recognize multiple levels of powers, via the masteries that you note. The only real issue, on the high end, is what happens at the boundary conditions between power scales. They're not totally smooth, probabilistically speaking, but it's generally OK.

A similar attempt was made with the original RuneQuest system. You can probably find it if you search on the web for "Steve Mauer's HeroQuest". RQ had always had a "special" success at 20% and a critical system at 5%. If you expand that to an ultra-crit at .5%, something else at .1%, etc, you effectively have multiple power levels and can thus measure relative levels of success in a meaningful way. (You also need a method to offer increased experience as the skill level increases, or your scaling breaks down, because characters don't level up.)

To tie this all back in to Travis' article, you have to think about scaling beginning with character creation. GURPS is my favorite example. Although it's theoretically a Generic Universal Roleplaying System, it has scaling problems at both top and bottom. For example, when SJG produced _GURPS Bunnies & Burrows_, they had to modify their scale down to allow for bunny characters. Where before a 10 character attribute had been "average human", now it became "average bunny", so that all of your B&B characters weren't stuck with stats of 1 or 2 in all the physical attributes.

But as a result, you can't crossover your B&B characters with GURPS Traveller, or whatever ... thanks to scaling limitations in core character creation that weren't considered when the game was originally written.

Shannon

[Nom]

Shannon,

Amusingly enough, I only realised the connection between yourself and HW three days ago. I had my HW rulebook out and noticed "Shannon Appel" on the cover. Suddenly the lightbulb winked on. :)

The only real issue, on the high end, is what happens at the boundary conditions between power scales. They're not totally smooth, probabilistically speaking, but it's generally OK.Yeah, I noticed your mechanic gets a bit wonky at 1,2 and 19,20 when one of the categories gets squeezed out of existence, but I couldn't think of an elegant fix. You could make the special values float a'la RQ, but that adds complexity.

(You also need a method to offer increased experience as the skill level increases, or your scaling breaks down, because characters don't level up.)I'm glad you mentioned this, because it's the other aspect of scaling that many systems don't do well (and incidentally that HW does very nicely). Is your system experience independent? Will both your game mechanics and experience mechanics work equally well for veteren characters as novice characters and everybody in between? Surprisingly few existing mainstream systems handle this cleanly.


Let me then ask a different but related question - how important do you consider progression 'objective gameplay' with increasing 'level'?

I'll define that in contrast with subjective gameplay. Subjective gameplay is how I perceive what my character is doing. Am I a mere peasant holding off bandits or a masterful hero battling dragons, a scribe working a masters books or a castellan ruling my king's castle? In any vaguely achievement based game, I want to feel that my character is somewhat greater than he/she originally was. In a more introspective setting, this simply may be the working out of the story in game.

Objective gameplay then is about mechanics. Do the mechanics substantially differ as the character progresses? D&D is a clear case where they do - characters move from being very simple (and dying if they sneeze too hard) to having a bewildering array of options. Hero Wars is the opposite, there are really only two or three fundamental mechanics, and these persist regardless of the stage of the game. Fully diceless systems are also squarely in this camp.

Is having the objective gameplay change throughout the lifetime of a character a good thing or a bad thing? What are the advantages and disadvantages?

[ShannonA]

Yeah, I noticed your mechanic gets a bit wonky at 1,2 and 19,20 when one of the categories gets squeezed out of existence, but I couldn't think of an elegant fix.

We couldn't either, and we thunk about it a lot.

Let me then ask a different but related question - how important do you consider progression 'objective gameplay' with increasing 'level'?

I think it depends on the type of gameplay you've developed. If you look at the Bartle theory of online gaming, it presupposes four types of gamer: achievers, killers, socializers, and explorers. I've touched on it in my own columns #25 and #42 of TT&T, which you can find over at http://www.skotos.net/articles/TTnT.shtml.

If you've built a game that is at least partially directed toward achievers, you need objective gameplay progression; if you've built a game that is at least partially directed toward socializers, you need subjective gameplay progression.

I don't think there's much doubt that D&D fits into the more achievement camp and Hero Wars into the more socializer (storytelling) camp, and thus the individual types of gameplay progression each work well for them.


Is having the objective gameplay change throughout the lifetime of a character a good thing or a bad thing? What are the advantages and disadvantages?

Generally, if you're playing in an achievement type game, I think it's a good thing. Prime points:

1. Allows for increasing level of complexity, and therefore a deeper decision tree, once players are more experience with the game system.

2. Allows for different type of gameplay to offset boredom in a long term campaign.

I personally don't see many deficits, though a player could, of course, have the desire to always have their game be the same. But then you play a Hero Wars, where the game system is just a crutch for the storytelling, not a means in and of itself.

Shannon