Why Blades in the Dark feels less swingy than d20 – and why the bell curve (and variance) aren't the main reason


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I'm a big fan of dice pools/bell curves for a number of reasons, but the idea that it's inherently less swingy than linear distributions is absolutely a fallacy. I didn't even realize anybody was claiming that.
Its like one of the main reasons advocates of dice pools claim. You really never saw that claim? Its almost ever one of the first ones that comes up in the 3d6 vs d20 discussion. I also assumed it.

But me being a 3d6 hater, I love this post for giving me one more point against it for the next neckbeard discussion.
 

Its like one of the main reasons advocates of dice pools claim. You really never saw that claim? Its almost ever one of the first ones that comes up in the 3d6 vs d20 discussion. I also assumed it.

But me being a 3d6 hater, I love this post for giving me one more point against it for the next neckbeard discussion.
As per my earlier post, the use of a bell curve (eg 3d6) means that the raw dice output is more predictable than the raw dice output of a linear distribution (eg 1d20). However, it does not immediately follow that a game system using dice that provide a bell curve is a more predictable system than one whose dice provide a linear distribution.

You'll struggle to convince the true bell curve zealots of that, though.
 

After thinking about it more, I realized my earlier description (d20 shift) was still imprecise.
It’s not really that “the curve simply shifts left or right”. It behaves more like a balance scale with two pans:
  • Left pan: Crit Miss + Miss
  • Right pan: Success + Crit Success
When you increase your bonus by +1 (or lower the DC by 1), each of the three thresholds moves by 5%. This causes 5% probability to shift from the left pan to the right pan (or vice versa).

Inside each pan, there is also an internal reweighting: some Miss probability is converted into Crit Miss, and some Success probability is converted into Crit Success (nat 1/20).

Additionally, the Nat 1 and Nat 20 rules act like anchors at the extremes, keeping the crit chance elevated for longer when the success threshold moves far from the middle.This makes the d20 resolution system more nuanced than a simple linear shift would suggest.
 
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As per my earlier post, the use of a bell curve (eg 3d6) means that the raw dice output is more predictable than the raw dice output of a linear distribution (eg 1d20). However, it does not immediately follow that a game system using dice that provide a bell curve is a more predictable system than one whose dice provide a linear distribution.

You'll struggle to convince the true bell curve zealots of that, though.

The argument (that curves are less swingy) could be true if the amount over/under mattered. But if it's straight success/failure against a DC then....no.

EDIT: People might also have different interpretations of "swingy".
 

Which is often that a “mixed success / success with complications / etc” feels worse then a failure somehow if posts on the internet are to be believed!
Well, mixed outcomes almost never feel exactly like success to me, which means games that intentionally center that outcome in the probability rarely feel awesome to me in play. I'd probably feel less like the game was lying to me if it just called those "partial failures."
 

Well, mixed outcomes almost never feel exactly like success to me,

Um....isn't that the point? :)

My only complaint...with my GM hat on...about "success with complications" is the difficulty of coming up with original complication on the fly.

But in general I find, "You pick the lock, but now your lockpick is jammed inside the lock, and you hear footsteps coming" to be a lot more interesting (and fun) than, "No."
 

Um....isn't that the point? :)

My only complaint...with my GM hat on...about "success with complications" is the difficulty of coming up with original complication on the fly.

But in general I find, "You pick the lock, but now your lockpick is jammed inside the lock, and you hear footsteps coming" to be a lot more interesting (and fun) than, "No."
Blades in the dark calls them successes--in that graphic upthread, they're not in the "bad outcome" bundles--and tells the players they have a fifty percent chance of succeeding at a thing, even with just the one die. If those mixed outcomes don't feel like successes, that can very easily feel as though the game is lying.

The game text is pretty explicit in wanting players to lean into those partial failures and think of them as successes, so the fact they don't feel like successes to me--as in, not ever--is not the game working as expected/desired.

My take is that you want things when you make a check, and if you fail you don't get some subset of those things. A partial failure to pick a lock might mean "you hear footsteps" or it might mean "whatever's on the other side of the door has the drop on you," or it might mean "you've set off some silent alarm and now other things are going to be more complicated for you." I probably wouldn't deploy "your lockpick is broken/jammed" on something less than a pretty extreme failure, and in that case I'd probably include one or more of the other options (though you might still open the lock ...).
 

Um....isn't that the point? :)

My only complaint...with my GM hat on...about "success with complications" is the difficulty of coming up with original complication on the fly.

But in general I find, "You pick the lock, but now your lockpick is jammed inside the lock, and you hear footsteps coming" to be a lot more interesting (and fun) than, "No."
This is the crux of my issue with the system. Depending on the GM’s interpretation, that success with complications can feel either like a minor success or it can feel like a failure. In other words, the minor success can feel more punishing than if the player chose not to take the action at all. That all depends upon the GM, though. Two different GMs may have a different complication, and I think that’s why some people walk away from the game feel good about it and others kinda bummed.
 

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