I mentioned this idea in another post last summer in regards to wandering monster checks, but I think it’s actually a rally nice principle that can be applied to all dice rolls without a defined die size and target number.
I’ve talked about accessibility of RPG rules in the past, both here and in several other places, and my personal experience as a GM with ADD has always been that my brain very easily becomes overloaded when juggling numbers at the same time as I am trying to follow a conversation. The trivial task of putting the initiative counts of six to eight participants in an encounter into a descending list has always been the single most challenging thing and greatest struggle to me about running games. (Now I always use group initiative to skip the whole issue.) But another thing that isn’t always easy for me in the heat of the action is probabilities like “2 in 6”. I rolled a 4, is that a success or not? Do we count the lowest two numbers or the highest two? This can be really easy stuff, but for my brain that’s something that takes up completely disproportional amounts of processing power. Not a good situation.
My solution is to make any such rolls a probability of “1 in 4”, “1 in 6”, “1 in 8”, and so on. If I’m using material that uses other odds, I translate them into whichever “1 in N” probability gets closest and write that in my notes. The result of this is that even when my mind is getting overloaded with input from the players and I am trying to establish what happens next, I only have to look at the die in front of me and remember “Something always happens on a 1!”
If it’s not a 1, then nothing happens. Proceed as normal. If it’s a 1, that always means the answer to “does X happen?” is always a yes. I’ve adopted this method as a solution to my specific personal problem, but I think it’s a really neat way to handle a wide range of rolls in general. It’s also helpful for new players who are still trying to figure out what’s actually going on all the time. On top of that, there’s a dozen different ways of how you can roll a die to determine the outcome of an action. Sometimes they have to roll higher than a number on their character sheet. Sometimes they have to roll lower. Sometimes they roll a die and add a number from their character sheet and the GM tells them if it’s a success or not. Sometimes they roll d6 and a 1 is a success, other times they roll a d8 and 7 is a success. Any time you can simply tell a player “just roll that die, when it’s a 1 something happens” is a moment where that player has a lot less new information to process.
I also think it helps with speeding along play and creating additional excitement by simply having a player roll a dice in the middle of the table, and since they’ve seen the same thing a dozen times before now, they already know “something always happens on a 1!”, without you having to explain to them how the odds for this specific roll are working. And by having established that something always happens on a 1, there is no ambiguity on whether that roll really mattered or you arbitrarily decided the outcome in disregard of the die. When the players see a 1, they can jeer in excitement or despair without even having to look at you. In my perception, this is a very useful tool to make players realize that the fates of their characters are entirely in the hands of themselves and random luck, and that trying to figure out what the GM wants or expects doesn’t make any difference.
You could of course switch it around and say “something always happens on the highest number of the die”. But that requires one additional mental step to get to the actual result, which is identifying what type of die has just been rolled. I think everyone who’s played with new players know that it takes them a good amount of time to look for the die in front of them that has the same amount of numbers that you just told them to roll. It may not be immediately obvious if a die sitting in the middle of the table and showing a 10 is a d10 or a d12. And in my personal situation, when I am trying to run an encounter with lots of players chattering in excitement, staring at a die in front of me and trying to remember what meaning there was behind the die I just roll can take me two or three seconds. Figuring out if that 10 on the die before me means something or nothing is an additional step I just don’t need if it doesn’t add any additional value to the game. And ADD is not an uncommon condition, anecdotally even less so among RPG players. I would hazard to guess that more groups have one than not, and wouldn’t be surprised if a good number of them is affected by similar forms of mental overload as me. Even if this seems to trivial to be pointless to you, there might very well be a player in your group who’d really benefit from it. So “something always happens on a 1!”.