Modding One Hour Wargames, Part 2 bis: Combat Results Variance

In the previous post, I explained why I find OHW’s rules so elegant and robust. This is just a short add-on note I felt urged to write when I considered a few of the design choices in the game.

As you might know, there are two types of combat result modifiers in the game: additive (either -2 or +2 to the rolled result) and multiplicative (the result is multiplied x2, x0.5 or 0.25). An intriguing ‘hidden’ feature of the game’s math is that these two types of modifier turn out to be largely equivalent when considering the amount of turns needed to eliminate an enemy unit (see previouspost).

A normal unit needs 5 turns to eliminate a fresh opponent. This is reduced to 3 turns both in advantageous situations (x2 hits multiplier) AND if the unit has superior attack power (+2 hits). This might prompt the question: then why bother having both types of modifier? Couldn’t strong units just inflict x2 hits, or advantageous situations give a further +2 to the roll? Well, I think Mr. Thomas has it right once again, since I think there two advantages in having both additive and multiplicative modifiers.

Simplicity: Additive modifiers are only dependent on the attacker unit, and nothing else. Multiplicative modifiers are situation-dependent only. There’s no math whatsoever involved prior to the roll, in the sense that you don’t have to add several modifiers, keep the result in mind, roll and apply the calculated modifier. Of course the very notion that this might be problematic may sound ridiculous to us grognards, but I think it’s a rather nice touch that lowers the entry threshold for non-gamers and kids.

Variance: Additive modifiers are considerably more predictable than multipliers, and don’t change how results are spread around the expected value. Stacking positive multipliers would result in far too unpredictable distributions of results – a standard attack with a x4 multiplier could inflict 4-24 hits, which would just throws game (and scenario) balance out of the window. Conversely, stacked fractional multipliers don’t pose the same problem, (they just result in a handful less hits here and there, especially if paired to the ‘always round up’ rule).

So what?

This is just a quick note to myself (and other prospective OHW tinkerers): think twice before messing up with OHW’s hit roll variance. Don’t allow multipliers to go higher than 2x. Additive modifiers larger than +2 seem safer on paper.