Wednesday, January 1, 2014

The Importance of Finding Another Way (and AD&D Combat Math)

(This ended up being a lot longer than I intended, but once I started writing I just kinda went with it. Hope the party finds it helpful.)

This last session, I saw so many 2s, 3s, and 4s rolled by the players in combat, I swear I wanted to throw up in my shirt. And it wasn't just attack rolls. DM rolls a 2 for initiative? Players roll a 1. Players roll 5? DM rolls 6. Players roll 6? DM rolls 6. (All of those actually happened.)

So many unlucky rolls, how could the PCs possibly prevail?

That's what I was asking myself afterward, particularly when Jason mentioned a "dice bowl" idea where players can remove a d20 from a bowl of dice to re-roll an attack or save, then the party gets XP after the session for any dice still unused. It's a neat gimmick, a little game within the game that helps solve the fundamental "problem" of a party bogged down by terrible luck.

I'm always a little hesitant to make changes like this to my games. Partly because it feels like cheating, but also because it's hard to remove them without causing disappointment.

So, I took a step back and started thinking more deeply about what I was trying to solve, and specifically the combat math from Monday night's game. Let's take Alaric, the party's undisputed best fighter (actual rolls notwithstanding).

Alaric is a 3rd-level paladin that hits a well-armored (or very small/dexterous) opponent of AC 3 on a 14 or better with his longsword +1. (The math is THAC0 18 - AC 3 = 15 needed to hit, with +1 to his roll from the sword.) That's a 35% chance, an expected hit rate of about once every three rounds.

That's not super great to begin with, but passable enough to justify a swing, especially considering that the player doesn't know the opponent's actual AC during combat. But what about when the opponent is invisible? That's another -4 to hit (see here), which plummets his hit chance down to 15%, less than once every SIX rounds, on average.

Six rounds? The PCs are likely dead before then - and that's the party's best fighter.  I'm pretty sure the other three characters each need to roll a 20 in that situation.

That brings me back to the dice bowl idea, which subverts the "natural" AD&D combat mechanics in favor of the party. Now, if your hit chance is already around 40% or better, or if trying to survive some kind of save-or-die effect, the dice bowl is pretty helpful. But at 5-15% to hit an invisible enemy, a single mulligan roll doesn't improve the success chance all that much. Taking last session's rolls as examples, even if those 2s, 3s and 4s were all 12s, 13s and 14s, almost every one of them still would have missed. And that's a testament to the fact that, last session, luck wasn't really the problem. Knowingly or not (and I think mostly not), the PCs made very statistically poor choices.

The truth is, when you're up against an invisible enemy who's darting around and stabbing people in the back with poison, you're best off finding another way to address the issue. Attack rolls are normally well and good (not to mention a core element of the game), but in this situation the attack roll shouldn't have been plan A. Spells, chalk, rope, blankets, practically ANYTHING should be tried before swinging a longsword for a 1-in-6 chance to hit. Shooting 3s from half-court just isn't winning basketball.

And that's where D&D really shines, because RPGs are all about thinking outside the box to find another solution. For me, it's probably my favorite part of the game, the biggest reason I still DM and play. It's about stepping into your character's shoes and asking, "My life is literally on the line here, what do I try to do?" AD&D is awesome at accommodating that mindset.

The flip-side to this is that players can sometimes drift so far in the direction of "outside the box" that they forget the box even exists. This happens when you see a party trying to take down a warband of orcs by tying all their daggers together as some kind of ridiculous lasso-tripwire. This approach to combat tends to not be very lucrative either. You want to find the right balance between being creative and pragmatic.

So, having gone through all that, I think the first thing I can do to help with the "bad luck" problem is to show some typical hit percentages for our party:

Roll needed to hit...
PC/weaponLightly armored
opponent (AC 8)
Moderately armored
opponent (AC 5)
Heavily armored
opponent (AC 2)
Alaric (longsword +1)9 (60%)12 (45%)15 (30%)
Aginot (staff)12 (45%)15 (30%)18 (15%)
Leilana (spear)12 (45%)15 (30%)18 (15%)
Nora (short sword)11 (50%)14 (35%)17 (20%)

Look at those numbers closely, because there's only one in the whole grid that's higher than 50%. It's noteworthy that Nora has a +2 Dex bonus when firing her bow, making those chances 10% better (bows also can fire two arrows every round). Opponent invisibility effectively reduces any hit chance by at least 20%, so that's something to keep in mind as well. Incremental advantages like being on higher ground can impact the rolls, too.

The point is, before blindly choosing to bust out sword or mace, try to think a couple rounds ahead to how events might play out if the dice fall like the numbers suggest they should. If that result looks a little grim for the PCs, you may want to reevaluate your options to see if there's another approach worth trying.

In closing, my games have never been strongly focused on mechanics, and I don't want players to feel like they have to memorize the rule books to play. A side effect of this, though, is that I probably need to do more to ensure that players are comfortable enough with basic combat math to have a feel for when it makes sense to attack as opposed to looking for other ways to win.

Sometimes it definitely makes sense to swing the sword. Sometimes it's the only option you really have. But often, success or failure is ultimately determined before any rolls are made at all.

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