How often should you hit in Old-School RPGs?

Most retroclones seem to use the same standard numbers for Leather (light), Chain (medium), and Plate (heavy) armor: 12, 14, and 16, respectfully, with unarmored foes counting as AC 10. There is one prominent exception I've noticed, which is Lamentations of the Flame Princess (LotFP). LotFP makes the default unarmored AC 12, and everything else adjusts accordingly (so, light armor is 14, medium armor is 16, and heavy armor is 18). 

I found this counter-intuitive at first, but as I wondered on whether there's a good way to fix this. As I started exploring to-hit probabilities, I decided to make a comparison between four prominent old-school systems to get an idea of what the options are. I used three B/X retroclones - LotFP, Old-School Essentials (OSE), and Labyrinth Lord (LL) - and one ODD clone, White Box Fantastic Medieval Adventure Game (WB) 

I decided to see how different classes' chances to hit lightly and heavily armored enemies changes as they level up. This is assuming ability modifiers of 0 of course, which isn't necessarily realistic, but so be it. Let' start with level 1

Level 1 vs. Light Armor

	OSE	LotFP	LL	WB
FIGHTER	45%	45%	50 %	45%
CLERIC	45%	40%	50%	45%
MAGIC-USER	45%	40%	50%	45%
THIEF	45% [65% if sneak attack]	40% [60%]	50% [70%]	45 [55%]

Level 1 vs. Heavy Armor

	OSE	LotFP	LL	WB
FIGHTER	25%	25%	25 %	25%
CLERIC	25%	20%	25%	25%
MAGIC-USER	25%	20%	25%	25%
THIEF	25% [45%]	20% [40%]	25% [45%]	25 [35%]

So, at level 1 we see across the board that all PCs have a 40%-50% chance of hitting a lightly armored foe (so just under 1-in-2 attacks lands), and a 20%-25% chance of hitting a heavily armored foe (so around 1-in-4). LotFP is unsurprisingly in the lower end of this spectrum, due to the high armor values.

This also means sneak attacks are particularly important - as especially against plate-mail they can almost double your chances of hitting an enemy (with the exception of White Box which gives a piddly 10% additional chance to hit for sneak attacks). 

LotFP is interestingly the only system which gives the first level fighter an advantage in hitting enemies over other classes. 

Now let's see what happens when we enter mid-level play.

Level 5 vs. Light Armor

	OSE	LotFP	LL	WB
FIGHTER	55%	65%	65 %	60%
CLERIC	55%	40%	55 %	50%
MAGIC-USER	45%	40%	55 %	50%
THIEF	55% [75%]	40% [60%]	55% [75%]	50 [60%]

Level 5 vs. Heavy Armor

	OSE	LotFP	LL	WB
FIGHTER	35%	45%	40 %	40%
CLERIC	35%	20%	30%	30%
MAGIC-USER	25%	20%	30%	30%
THIEF	35% [55%]	20% [40%]	30% [50%]	30 [40%]

The differences between the systems are beginning to become more apparent:

 In OSE, the average chance to hit a lightly armored foe is now slightly above 1-in-2 for most PCs, and to hit a heavily armored foe it's around 1-in-3 for most PCs - and 1-in-4 for magic users. Labyrinth Lord and White Box are quite similar except for the magic-user still being the same as the cleric and thief and the fighter pulling ahead. 

In LotFP the chances remain the same as before for all but the Fighter, who now hits lightly armored foes 2-in-3 times, and heavily armored foes just under 1-in-2 times - quite a leap!

So, LL and White Box, an advantage has now been granted to the Fighter. In LotFP the advantage was already present but has become far more palpable. In OSE, it has neutralized (because by level 5, the cleric and thief have caught up to the slightly faster progression of the fighter), but Magic Users are now disadvantaged in comparison to the other classes. 

So what about the late game?

Level 10 vs. Light Armor

	OSE	LotFP	LL	WB
FIGHTER	80%	85%	85 %	75%
CLERIC	70%	40%	65 %	70%
MAGIC-USER	55%	40%	60 %	60%
THIEF	70% [90%]	40% [60%]	65% [85%]	70% [80%]

Level 10 vs. Heavy Armor

	OSE	LotFP	LL	WB
FIGHTER	60%	65%	55 %	60%
CLERIC	50%	20%	50%	40%
MAGIC-USER	35%	20%	40%	35%
THIEF	50% [70%]	20% [40%]	50% [60%]	40 [60%]

 

Now , OSE, LL and WB each have three tiers: fighters have the highest chance to hit (on average, 4-in-5 attacks hit lightly armored foes, and 3-in-5 hit heavily armored foes); then thieves and cleric (on average 2-in-3 attacks hit lightly armored foes, and 1-in-2 attacks hit heavily armored ones; and finally Magic-Users (on average, 3-in-5 attacks hit lightly armored foes; 2-in-5 hit heavily armored ones). 

LotFP is now quite different from the rest - its fighter overshadows those of the other systems, with it regularly hitting any type of foe, and leaving the non-combat classes far behind. 

So what do we make of this?

My first thought is: I think the fighter in OSE (and to a lesser extent, Labyrinth Lord) seems like quite a boring class. The idea of him pulling ahead of the cleric and thief at times (at level 4) only to be equal to them the next level seems very unsatisfying - though I haven't seen it in play. But my gut instinct would be that I'd rather just play a cleric and sacrifice the higher hit die.

White Box is a bit of an outlier, because it also lets fighters hit multiple low-HD enemies in a single round, which is quite interesting, and can be useful against hordes of mooks - and lets mid-high level fighters feel cool when they take down several enemies in one turn. 

LotFP is very interesting, because fighters become absolutely essential the longer play progresses, as increasingly higher HD enemies are encountered (unless one is forsaking any semblance of balance whatsoever), and clerics and thieves (specialists in LotFP) become far more interested in non-combat abilities than combat ones (even with a sneak attack, a 10th level specialist hits at most 3-in-5 times. Which seems quite discouraging, but on the other hand, the LotFP version of sneak attack can potentially deal boatloads more damage than the other systems, so the risk is greater - but so is the reward). 

This may affect a whole range of player choices, encouraging them non-fighters to avoid combat even in later levels, and affecting how much non-combat classes in each system care about magic items.

This raises some questions, however - how often should one hit as a base level? And do we want that chance to go up for everyone? Or only for some classes?

In any case, I think if I ran OSE, I would make a house rule to add the White Box multi-attack power for fighters, to make them more interesting.

On the other-hand, I think I would consider raising the attack bonus for Clerics in LotFP, but at a slower rate than Fighters (perhaps at levels 3, 6, and 9? that would still keep the fighter far above the cleric), if only to further differentiate clerics from magic-users, who tend to have access to more powerful (and arguably more interesting) spells. The Specialist could possibly also stand to gain an attack bonus, perhaps at a slower rate (levels 4 and 8?) - but I'm not sure it's necessary.  I don't see any reason for Magic-Users' chance to hit to go up. 

I do wonder if there's a way to mess around with LotFP's attack bonuses so the Armor rates match other OSR games without undoing the basic probabilities (and without giving players a minus for their attack rolls at level 1 - that just feels gross), simply so it's more intuitive (Unarmored at 10 seems ideal to me). Will have to think about that.