Do you want to Ask the Angry GM a question? It’s easy to do. Just e-mail your BRIEF question to TheAngryGameMaster@gmail.com and put ASK ANGRY in the subject. And include your name so I know I can make fun of you, your name, your question, your inability to proofread, or your poor understanding of the concept of a BRIEF question using your proper appellation. And yes. Consider that a warning. If you want politeness, go ask the Hippie-Dippie-Sunshine-and-Rainbows-and-Bunny-Farts-GM.

Justin Asks:

I was doing some math work out of curiosity to see how much more likely you are to roll a 20 for each successive advantage die you used in D&D 5e, and was wondering why exactly you aren’t supposed to have advantage stack? You go from a 5% chance of a 20 with no advantage to around 10% to around 15%, none of which seems game-breaking. It also seems like a cool way to allow characters prepare for some action or obstacle.

Notice that Justin properly proofread his brief question and included his name. I didn’t have to edit anything. I just cut and paste. He’s the example you should all strive to live up to. At least when it comes to how to ask me a question. When it comes to probability math and game design, you’re a little more lacking.

All right, let’s start with the math part. I’m going to assume you rounded off your numbers because you said “around.” And that means that you probably more correctly derived 9.75% for the chance of rolling at least one 20 on 2d20 and 14.266% for the chance of rolling at least one 20 on 3d20. If that’s the case, good for you. You know how to calculate the probability that at least one of a number of independent events will happen.

But you’re still bad at probability. Why? Because you’re not focusing on the actual chance of success or failure here. The chance of an action succeeding or failing is actually based on whether the die roll meets or exceeds a target number. A DC. Right? You know this.

Now, the thing is, DCs and modifiers change. The only constant is the d20. But we can actually make a few assumptions and see how the math skews. For example, an average difficulty task is defined as having a DC of 15 (PHB 174). On average, a PC attempting a task at low level is probably going to use a skill they are proficient with and an ability score in which they have a positive modifier. Otherwise, they’ll get the Hell out of the way and let some other PC try. So, let’s assume they have a +2 ability modifier and a +2 proficiency bonus. Not ridiculous assumptions. Given that, the PC needs an 11 on the die because 11 + 4 is 15. This is the kind of brilliant mathematical insight that makes me the genius I am, I know.

The chance of rolling an 11 or better on a d20 is 50%. There’s 20 different numbers on the die, and 10 of them are 11 or better, right? Fine, so what are the odds of rolling an 11 or better at least once on 2d20? Well, it’s 75%. That’s a pretty big jump. Effectively, in that situation, it’s like having a +5 on the die. Fine. So, what are the odds of rolling at least one 11 on 3d20? That’s 87.5%, which is roughly another +2.5. The probability of at least one 11 or better out of 4d20 is 93.75%, which, admittedly, is another +1.25, and you can kind of see the pattern here. And that’s because I chose easy numbers to work with. But if we were to assume the player needed a 15 on the die, the probabilities for at least one 15 or better would be 25% for 1d20, 43.75% for 2d20, 57.81% for 3d20, and so on. And if the player needed a 5 on the die, the probabilities for at least one 5 or better would be 75% for 1d20, 93.75% for 2d20, 98.44% for 3d20, and so on. And from that, we can see two basic patterns. First, the effect of Advantage is most pronounced when the player needs a 10 on the die roll. The farther you get from that average result, the less pronounced the effect of Advantage is. Second, there’s a rapidly diminishing return on additional “advantages.”

And that means – well, it means that you’re right. Roughly speaking, allowing multiple levels of Advantage or Disadvantage to stack wouldn’t actually break the game. Because the first level of Advantage is where all the juice is and it is at its juiciest when things are 50-50, and the game is actually centered more around 65-35 as the sweet spot for success rates. So why not just allow multiple levels of Advantage to stack?

Well, I don’t work for WotC, and I wasn’t technically there when they invented the mechanic. So, I’m only guessing, but here’s how I see it. First, the impact of multiple levels of Advantage or Disadvantage is pretty minimal. But people are very bad at understanding probabilities. Probabilities aren’t intuitive. I mean, did you KNOW the odds of rolling at least one 20 on 3d20 BEFORE you sat and did the math? And did you know the odds of getting at least one 15 on 3d20 BEFORE I did the math and spelled it out? Probably not. And that means players might burn resources chasing extra layers of Advantage that aren’t going to pay off. So, it becomes a sort of trap. Players WILL chase layers of Advantage if you let them. I guarantee it. And they will burn lots of resources when they think there’s a lot riding on the roll. It just won’t work out the way they think it will.

But there is another issue too. And that’s the way Advantage and Disadvantage interact. As it stands right now, they cancel each other out. That’s easy. But if you allow them to stack, you can pile on multiple Advantages and multiple Disadvantages, add them all algebraically, and come out with Triple Advantage or Double Disadvantage. Is that a problem? Not really. But the whole point of Advantage was to streamline things. Once you’ve identified ONE source of Advantage and/or ONE source of Disadvantage, you’re done thinking through the situation. In 3rd Edition – and Pathfinder – you could end up spending a lot of time identifying and adding up situational modifiers. And players would chase them with spells and other limited effects to stack the dice in their favor. And that slowed things way down in complicated situations.

The Advantage mechanic was invented to do two things. First, to streamline the whole situational modifier thing. Second, to find a way to give a substantial bonus without inflating the numbers of the game. That second thing – which the designers call “bounded accuracy” – isn’t important here. I just mention it because, if I don’t, some dumba$& will remind me about it in the comment section since Mearls and Co. bragged about it like bounded accuracy was the Second F$&%ing Coming. If you allow it to stack, you get rid of the streamlining. Okay, fine. Maybe you don’t like the streamlining. But you’re removing the streamlining in such a way that every layer of complexity in a situation has a smaller and smaller impact on the actual outcome. And none of that is obvious or intuitive to the players. They will chase the complexity and pile it on.

The thing to remember is that game mechanics aren’t ONLY about math. They are half math and half psychology. And sometimes, the game designer has to protect the players from ruining the experience for themselves.

Tristan C. asks

What would be your top/most important tips for someone wanting to learn to DM, but is kinda new to D&D/tabletops in general?

Good job, Tristan! You asked a nice, brief question and I can… wait… what’s this? Oh good f$&%ing gravy, it’s a giant paragraph of CONTEXT for me to edit. Oh, joy. I just love people assuming I’m too stupid to answer a straightforward question without an entire paragraph of annotations. At least it’s just ONE paragraph. Let me see if there’s anything important in all of this crap.

I, being the idiot I am, am currently designing my own future campaign while still learning about D&D. My introduction to TTs…

Okay. No. Let me summarize this.

“I’m Tristan. I’m an idiot, and I’m inventing my own campaign. I’ve only played a few simple adventures and helped playtest a game, so I know basically how RPGs work. Now I’m running a game for actual friends, and after five adventures, they are still coming back, so I figure I’m ready to run the campaign. I even started putting the plot points into the campaign. But I have no confidence in myself, and I’m afraid I’m going to be terrible. I’ve only been reading your articles for a few days so I haven’t had a chance to read all of your brilliant advice about how to start gamemastering and when to build your own campaign and I want to know when you think I’m ready to start my own homebrew campaign even though you’ve never met me and I admitted I know I’m not.”

Good question, Tristan. And thanks for all that background. I certainly couldn’t give a thorough answer to a question as simple as “I don’t have much experience with RPGs and I’ve only run a few short sessions for my friends, but I want to start my own homebrew campaign. When am I ready to do that?”

First, if you have to ask if you’re ready to run your own homebrew campaign, you’re probably not. But if you wait until you’re ready, you’ll never f$%&ing run it. Catch 22, huh? But here’s the thing: you weren’t ready to start running games for people at all. And you did that anyway. And that’s because, if you want to be good at something, you have to be willing to be bad at it first. So, I wouldn’t worry if you’re ready or not. Because no one is ready to start running games. No one.

I tell people there are three basic skills every GM has to learn. Those are the minimum things required before you can say you can run a game. The first is Narration. That’s the ability to tell your players what the hell is going on, invite them to act, describe the results, and move them from scene to scene. Basically, it’s your ability to talk to the players about the game world. The second is Adjudication. That’s the ability to determine what happens when you finish talking and one of the idiots at your table says something that sounds like “my character takes this action.” In short, it’s the skill of figuring out the outcome of the players’ choices and actions. If you can describe the world and the situations to the players and you can tell them what happens when they start f$&%ing with the world and the situation, you’re as ready as you’re going to be.

Oh, wait, the third skill. The third skill is the ability to manage a group of human beings like a socially capable human being yourself. I call that Administration, but it’s really a matter of just having basic social skills you should have picked up from your family and in early grade school. If you can lead a group of people and resolve conflicts between them, you’re good.

That said, you don’t have to actually be GOOD at any of those things. You just have to be capable enough to muddle through them. If you’ve run five games already and the players are still coming back, and none of the players have killed any of the other players, you’re probably Narrating, Adjudicating, and Administrating perfectly fine.

So, fine, start your campaign. But I’m going to give you two pieces of advice and one big warning. The advice will hopefully give you a better chance of succeeding. The warning will let you know that you’re going to f$&% up eventually. And that will lead to a third, interconnected piece of advice. You can take the advice and warnings, or you can leave them. I don’t really care. I don’t have to sit at your table.

First, the warning: your first campaign is probably going to fail to hit any sort of ending. It’s going to fall apart, or you’re going to lose control of it in some way you feel you can’t redeem or something. It’s going to die before its done. Very probably, anyway. There’s always a chance it won’t, but don’t count on that. Just know that going in. Honestly, that’s not even unusual. Most GMs leave a long trail of the smoking remains of unfinished campaigns behind them. And that’s because we – as GMs – plan everything too big except the ending. The ending we don’t plan at all. And if we do plan for the ending, we get excited and lose sight of the ending, or we let everything expand beyond the ending. My current campaign – the one I just started – is supposed to be a limited, six-month campaign and I know the three or four different resolutions that can end it already. But I also know it’s going to stretch into eight or ten months or a year, and I’m hoping the players fall in love with that before they figure it out, so they’ll stick it out longer. Or else it’ll be another unfinished campaign in the Angry Graveyard. Or it’ll be a total party kill (TPK) before then. That happens a lot too in my games.

Point is, your campaign is going to die. Especially because you’ve never done it before but you’re excited, and you have big ideas, and it’s going to be awesome, and you have no actual idea what goes into planning a campaign. Just be ready for that. And don’t even try to avoid it. Because you can’t. Plan it as big and grand and exciting as you want. Because your excitement is more important than anything else right now. The most important thing you can have when you’re trying to learn a new skill is excitement. The excitement acts as a balm against all of the failures you’re going to endure. The excitement ensures you’re willing to keep being bad at something.

That said, run a campaign you like and one you’re excited about, but keep your feet on the ground. That’s the third piece of advice. The one that comes out of the warning. It’s okay to dream, but don’t hold on to your dreams too hard. If you’re too attached, you might not realize that things have turned sour and you’re not having fun, or your players are getting bored, or the campaign is going in circles. And you might try to stick it out a lot longer than you should. You can always start a NEW campaign, after all. But if you kill your players’ sense of fun before you get there, they might not want to start it with you. Try to stay a little detached. As you’re writing your campaign, make sure you’re not so lost in your dream project that you’re going to end up depressed when it fails.

So, warning and third piece of advice out of the way, let me give you two good pieces of advice.

First, start clean. Don’t try to continue your little five adventure story and turn it into a campaign. Just tell the players flat out that you have an idea for a campaign and you’d like to try to run it. An actual, ongoing story from beginning to end. And let them make all new characters that fit the campaign. Give them a chance to build some excitement for the campaign that’s akin to yours. They might be attached to their current characters, but it’s a good lesson for players to learn to not be too attached in case one of their dumb characters dies.

Starting clean resets everything. This was your shakedown tour. This was your first attempt. It might have been fun. But it’s time to leave that behind and get serious. And to show your players what serious D&D is like. Pitch them the idea and let them develop character concepts attached to that idea. It will also psychologically prime your pump for running a full-on campaign as a real GM instead of “still learning how to do this s$&%.”

Second, you mentioned in the part of the e-mail I cut out as boring and useless that you were considering having a Session Zero. And I think that is a very excellent idea. It makes it increasingly likely that you and your players will end up building a game that has the best chance to go for a long time before it completely and utterly fails. It might even succeed. But I wouldn’t bet on it. Now, that Session Zero thing tells me that you’ve been reading my stuff. So, you know what a Session Zero is and what the point is and how to do it well. But it’s only going to work with a fresh, clean start.

In the end, you’re not ready. But that’s not a good enough reason for you to not try. So, try it and see. Make a clean break, a fresh start, gather your party and venture forth. Sell them a great campaign. Get them invested. Make new characters. And have at it. You’ll probably end up having a lot of fun. Right up until the moment the s$&% hits the fan, and you realize you have to start something else.

And that moment – the moment when you have to throw away tons and tons of work you’re totally attached to because of some stupid thing you didn’t see coming – that moment is when you’re a REAL GM.