I apologize for the subject heading. I couldn't really come up with a good subject line.

So, in Pendragon all modifiers are applied to the skill/trait/stat being rolled rather than the die roll. With one exception: if skill/trait/stat is above 20 (or below 0) then a modifier is applied to the roll. This sometimes leads to confusion, especially when you're making a lot of rolls for different characters. Sometimes I am rolling for 6 different saxons in a round and I forget to apply the -5 for fighting a mounted target until I after I roll. "He rolled a 15... +1 is a 16. Oh wait, he gets a -5, so his weapon skill is 16... crit! No wait no, he doesn't get that +1 now so that was actually 15 he rolled which is not a crit." I do this... not constantly, but it has happened a fair number of times.

Also one of my players is really really bad at math. (I rolled a 16... I have a 25 skill right now? is that a crit?)

I was thinking, what if instead applying a modifier to roll, having a trait above 20 turned low numbers into crits?

So at 21 skill, you crit on a 20, or 1. Anything is else is just whatever you roll.

For anything from 21-29 you literally just use that second digit.

The actual formula being: you crit on any roll of (trait-20) or 20.

I haven't actually implemented this idea, but I have discussed it with my players. None of them found the concept objectionable, but I lack the initiative to actually make a change.

I don't think this would affect probability of criting in anyway. But I am curious how other people would perceive it. Would you feel robbed if a 19 was just a 19 for anyone short of Lancelot? I know a common complaint* about Pendragon is the fact that there is not a single consistent 'rolling high is good' or 'rolling a 20 is good' paradigm to the rolling system.

*I consider it more of an amusing curiosity myself.

Mathematically, it seems to be the same, so I don't see a problem with it. On the other hand, I don't really see a problem with the skill calculations either, but that might be because I am playing mainly online, so I will type down the modifiers to the skills when calling the dicebot. I can see how that would be slowing things down at the table, although you'd still have to remember to add all the modifiers. One thing I do to make life easier for me is go through the opponents one by one: "OK, so your guy was knocked off his feet last turn and is now struggling up. That is +-5 modifier. What do you do? OK, roll. His skill is 21-5 for getting up... That is 16..." And in a ftf game, I would roll at that point myself. (To reduce the online clutter, I roll all enemies on the single line.)

Ok this is how I handle it.

I handle things per PK, and then per opponent.
First I determine all the modifiers.
Add all modifiers to the skill, so you get a modified skill.
Roll dice.
For skills higher than 20 roll is critical if roll is equal or higher than 20 minus points above 20. So a skill 25 means a roll of 15 or higher is a crit (20-5).
For skills of 20 or lower. Critical is modified skill value. Lower is a success, higher is failure or fumble (if 20 is a failure).
I do not alter the die roll itself, only the possible result.

Example:
Two saxons attack a PK.
Saxon 1 has an axe and shield. He is inspired by his hatred. His skill is 15.
Saxon 2 has a great spear. He is also inspired by hatred. He has a skill of 15.
PK uses sword and shield. Skill is 18

Saxon 1:
Modifiers: -5 (attacking Pk on horse), +10 (inspire). Modified skill is 20 (15-5+10)
He will crit on a 20, otherwise it is a succes.

Saxon 2:
Modifiers: +10 (inspire). Modified skill 25 (15+10).
He will crit on a 15 or higher (20-5). Otherwise it is a success.

PK:
Modifiers: +5 being on horse. Modified skill 23 (18+5)
He will crit on a 17 or higher (20-3). Otherwise it is a success.

You can write down all the modifiers down when you describe the scene. If it gets complex I usually do this.
To determine a critical you could write this also down on a paper and keep it at hand if you do not like to calculate the results.