Understanding SIZ: Deconstructing BRP

"SIZ: The characteristic of Size represents the average of an Adventurer's height and weight. Can an Adventurer see over something, or squeeze through a small opening, or be seen in tall grass?"
- Magic World

"SIZ: Size determines your character's height, weight, and bulk. Normal factors like gluttony or rigid diet can increase or decrease you character's weight, and therefore affect their SIZ."
- Basic RolePlaying 2nd

"SIZ: The characteristic SIZ averages height and weight into one number. To see over something, to squeeze through a small opening, or even to judge whose head might be sticking up out of the grass, use Size."
- Call of Cthulhu 6th

I never thought about Size as an attribute before playing Call of Cthulhu. For other games, it is always determined by a range of heights and weights that you get to select from, occasionally rolling modifying dice to randomize your selection. However, in making a Dark Sun conversion for BRP, I've needed to go in-depth to consider how, exactly, SIZ should work as an attribute for variant races, while attempting to maintain balance.

Human:

Starting off with the most default of races, humans in BRP systems are described as having flat 3d6 rolls for most attributes, while having 2d6+6 rolls for their SIZ, generating values that run between 8 and 18, with a racial maximum of 21, according to Magic World. Judging from the SIZ charts included in BRP sourcebooks, that would give humans the range of 5', 80 lbs to 7' 6", 420 lbs (Magic World has a typo on pg. 13 for their SIZ chart). However, according to Call of Cthulhu and Magic World, we're supposed to take averages of each to determine size. Though seven and a half feet is pushing it pretty far for a human, it doesn't sound ridiculous, especially in a fantasy setting. We're expected to look at the human as a default value, but let's see how the other races stand up to this precedent.

Dwarf:

Dwarves generate a pretty short end of the stick, no pun intended, when rolling up in BRP. Their generation roll is a flat 2d6 (with the possibility to add 3 on top of that-gauging from the human's max height on top of dice rolls), giving them potential SIZ values of 2-15, meaning the smallest generated dwarf would be 13" tall and weigh 11 lbs, while the largest would be 6'4" tall and 300 lbs. (BRP Character SIZ Chart, pg. 26).

Working through the other character races also creates various discrepancies like this, especially with the Athasian Half-Giant, who is, according to the Monstrous Compendium II averages out to 10-12' tall and 1600 lbs. So, 144" and 1600 brings us way off the standard SIZ tables of BRP's Character SIZ chart, though extrapolating from where the chart leaves us off at roughly SIZ 73 height-wise and SIZ 365 for weight. This is obviously ridiculous in terms of balance, and doesn't take into consideration the declining ratio of heights and weights as one moves further and further up the SIZ charts.

Instead, let's look at the Giant entry for BRP. Giant SIZ is 24d6+48, averaging at 132; taking half that (Half-Giant, remember) brings us to 66, not far from the estimated 73 extrapolated from the SIZ chart. However, this still gives Half-Giant-sized characters a ridiculous advantage in combat encounters. But-according to the Creature index in BRP, giants are roughly 16 meters tall, twice the height of Athasian D&D giants, which max out at 25'. What does this mean? That we need to half the SIZ for Giants in our conversion to 66, quartering them for Half-Giants, bringing them to around SIZ 33, a much more forgiving number for player characters.

What does all this number crunching mean? Well, basically that random generation of SIZ might be good for a single-raced game, but for something multi-racial/species, you may want to invest in the concept of semi-static SIZ values, and modify them based on another dice roll, such as a damage bonus.

Funny that I've done just that with my working BRP conversion of Dark Sun, isn't it?