What’s in a Roll: PART ONE


At its core the fundamental job of a DM is to adjudicate outcomes.  A player tells you what their character is doing and you, as the DM, tell them what happens.  Then you do that over and over again.  In its purest form that’s how D&D works.

Sometimes adjudicating an outcome just involves describing your world to your player.

PLAYER: I go to the town’s marketplace

DM: You find it easily.  There is a small square in the center of town.  Several merchants man karts with various wares for sale.  A halfling with a large scar across his face catches your eye.  He is standing outside a small covered wagon.  He waves at you to follow him and then turns and goes inside the wagon.

This type of adjudication is just story telling.  It doesn’t really requires specific rules and will look virtually the same regardless of which role-playing game you are playing.

However, sometimes adjudication requires some randomization.  A player’s character will try to do something difficult that has a chance of failure.  The basic rules of D&D tell us what to do in this case.

  • First. Determine the difficulty of the task.  This sets the target number the player must reach to succeed.
  • Second. The player rolls a d.20
  • Third. Add any bonuses the player’s character has to completing this task, e.g. attribute, skill or attack bonus.
  • Fourth.  Compare the roll to the target number.  If it is equal or greater the character succeed.  If it is less than the character failed.

All good? Not quite.  There is one more critical step.

  • Fifth. Narrate the result.

This final step is easy to overlook, but that is a serious (and all too common) mistake.  The nature of the success or failure of a task is what drives the action forward, but simply stating ‘you succeed’ or ‘you fail’ is how you play a board game, not a story based role playing game like dungeons and dragons.

Being a good DM requires you to navigate this five steps over and over again in a way that is enjoyable for everyone at the table.  It’s easier said than done.  I will be focusing a series of posts on discussing how to be better at this critical final step.  Weaving the die rolling aspect of the game seamlessly into a compelling narrative, that builds both story and character.

Before we can do this we need to understand just a tiny bit of math.  Namely, the artificial nature of the D&D math.  In the real world most tasks people attempt have a success rate that falls along a bell curve:

Before one can master dungeons, one must master algebra II

If I tried to jump as far as I could over and over again the results would look something like that curve.  The majority of my attempts would be about the same distance, with a few much lower or much higher than the average.  This would be true of most things we try.  A much better long jumper than me would have a similar curve, it would just be centered around a much higher number.

Importantly, this is NOT how D&D works.  A twenty sided die is just as likely to roll a one as it is to roll a 20.  The ‘curve’ is a flat-line with a 5% chance for any one number.

Didn’t this blog used to have jokes?

While less realistic, this type of curve is better for simplicity and drama.  But it creates a lot of hidden traps for a DM trying to narrate a game.

To illustrate this, imagine if when you tried to butter your toast you were just as likely to drop the knife onto your foot as you were to carve the butter into the shape of a flower.  This highlights just one of the challenges a DM faces when narrating the outcome of challenges in D&D.  The dice control a lot of the story and character at the table, but how you narrate these results has a greater impact at your table than most new DM’s realize.

There are two particular challenges we will discuss in detail in the next parts of this series:

  1. Handling a character who is very good or very bad at a particular task who rolls well or poorly creating an unusual outcome. i.e. the practiced archer who misses a simple target or the uneducated brute who deciphers the ancient runes.
  2. Handling multiple attempts to complete a challenge by different player characters who have widely disparate ability levels. i.e. the strongman fails to break down the door, but the scholarly wizard knocks it down with a lucky roll.

Until then, simply remembering that you are in charge of the game world, not the dice, will put you ahead of your average dungeon master.



  1. D&D is for those that can not play magic the gathering!

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