XP: The Big Switch, Pt. 3

One final observation on the difference between the monster XP award system between Original Vol-1 (linear in HD) and Revised Sup-I (parabolic in HD up to name level). Let's run our updated Arena simulator program under both these XP award systems. Parameters in use here are: 10,000 fighters, 200 cycles of one-on-one man-vs-monster combat, expected treasure awards being added, no special abilities simulated (so: somewhat safer for the men), -2 modifier given to the random monster level die.

Here's the resulting fighter population with the Revised (Sup-I) XP system:

And here's the population generated under the Original (Vol-1) system:

So this reiterates the expected finding that the Original (linear) XP system is much more generous to low-level characters (by a factor of fully ×10 XP value), and so we get somewhat more lower-level characters successfully leveling up, or in other words, the curve for advancing levels is noticeably more gentle.

Interpolating the curve at lower levels for the Revised system gives an advancement function of about y = k e^(-1.4x) (where x is the level, k the 0-level men-at-arms population, and y the population at any other level), or approximately dividing by 4 at each sequential level. In contrast, the Original system generates a simpler advancement function of close to y = k e^(-x), or approximately dividing by 3 at each sequential level.

Moreover, looking at the Original XP system, compare several possibilities for a modifier to the "Monster Determination and Level of Monster Matrix" (Vol-3, p. 10), versus the prescribed higher-level leader proportions from encounters with Men (Vol-2, p. 5):

We see that a modifier of -2 to the random-monster die roll in the Arena gives the best match (least sum-squared difference) to the leadership proportions given in Vol-2 (whereas previously under the Revised XP system we saw that a modifiers of -3 or even -4 from book was necessary). So in other words: Taken as a whole, the Original XP awards are closer to presenting an overall rational system of demographics in D&D.

I suppose the most important consideration is: How fast do you want your PCs leveling up, in terms of number of encounters faced? (And this was in fact used as the starting axiom for the 3E XP system, for example.) If you use the Original linear system, you will have PCs advancing through the lower levels somewhat more rapidly than many of us are accustomed to in D&D. In the period when Gygax was running pickup games in his basement every night of the week, perhaps he legitimately felt the need to slow down advancement, so that people weren't gaining multiple levels within a week of play. But for those of us who now play somewhat less frequently, perhaps the original system from Vol-1 -- which is actually a better representation of the real "value" of a monster, and also a more generally coherent demographic system, and also a lot simpler -- is still the more encouraging one.


Get the updated Java source code to the Arena program (v. 106) here.