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Dice are not rolling randomly

November 28 (5 years ago)
Steve
Marketplace Creator

OK we've been having this issue for at least a year: I am certain the dice in roll20 are not rolling randomly. Last night again we had about twenty rolls of 1 in a 2 hr session. And in some instances, rolling with advantage, two 1's. TWICE. Yes, yes, there's some algorithm that suggests there is an even distribution over a million rolls - But there is something bugged about the way the rolls are distributed over a short period, like 200 rolls. The dice rolls are just not right. And this is not a one off. Every session we play we can a weird number of 1s and 20s. Can someone please double check what's happening with the dice. It's enough to make us want to switch platforms. 

Cheers,

Steve G

November 28 (5 years ago)

Edited March 09 (5 years ago)
Andreas J.
Forum Champion
Sheet Author
Translator

No, the dice rolls are not broken

Human intuition on randomness is flawed, and here is an attempt to explain why

Roll20 has a page to show how random the rolls are. The thing about randomness that people don't often get, is that streaks" of "good or "bad" luck is to be expected. Truly random doesn't feel random.

But there is something bugged about the way the rolls are distributed over a short period, like 200 rolls

That is unlikely, but expected to happen to someone, at times, given the large number of rolls made on Roll20. You know how there exist people who have got hit by lightning more than once, or have won the lottery more than once? It's unlikely to happen to any given person, but the chance of it happening to someone, given large enough pool of samples, is extremely large.
The chance of something happening even at small scale is something we don't have an accurate intuition about, for example the Birthday paradox, which is the statistical oddity that with a random group of 23 people, it's a 50% chance at last two people share a birthday.

Math & Science behind randomness

Then there is also the fact that when the results are given instantly, it feels less random than if we see numbers flutter a bit before they appear. Slot machines and gambling games likely uses this trick of slowly showing the result to feel more random and increase the anticipation for the result

Psychology behind randomness (and why we're bad at perceiving it)

If you watch the "Randomness is Random" video, it demonstrate quite well how we think streaks of "good" or "bad" luck are longer and more prevalent than if we'd try to make a random sequence of numbers ourselves. That's why some random shuffle features on music playlists aren't always completely random, as they might prevent longer streaks of songs from appearing in their original order, or bias the system to try not to have too many songs from the same artist/album to play back to back.

Previous Forum Threads on the topic

This come up every now and then, and is repeatedly explained every single time. Here is a fairly long comprehensive list of previous discussions on the topic:

TL;DR: Humans have a bad intuition on what is or isn't random, and this have been debunked every time it's been discussed here.

November 28 (5 years ago)
vÍnce
Pro
Sheet Author


Andreas J. said:

Look for yourself how random it is. The thing about randomness that people don't often get, is that streaks" of "good or "bad" luck is to be expected. Truly random doesn't feel random.

But there is something bugged about the way the rolls are distributed over a short period, like 200 rolls

That is unlikely, but expected to happen to someone, at times, given the large number of rolls made on Roll20. You know how there exist people who have got hit by lightning more than once, or have won the lottery more than once? It's unlikely to happen to any given person, but the chance of it happening to someone, given large enough pool of samples, is extremely large.
The chance of something happening even at small scale is something we don't have an accurate intuition about, for example the Birthday paradox, which is the statistical oddity that with a random group of 23 people, it's a 50% chance at last two people shave a birthday.

Here are a few articles/videos related to how we perceive randomness, and why we're bad at it:

If you watch the "Randomness is Random" video, it demonstrate quite well how we think streaks of "good" or "bad" luck are longer and more prevalent than if we'd try to make a random sequence of numbers ourselves. That's why some random shuffle features on music playlists aren't always completely random, as they might prevent longer streaks of songs from appearing in their original order, or bias the system to try not to have too many songs from the same artist/album to play back to back.

This topic comes up every now and them, and most times have been discussed thoroughly:

TL;DR: My point is essentially that even if your rolls weren't random, you couldn't distinguish it that well from "true" randomness, given how humans in general doesn't have a good intuition of what is or isn't a random or close to random sequence. This have been debunked every time it's been discussed.

LOL

I'm not laughing at you or your group Steve.  We've all been there.  I've tossed a few dice over such rolls.

https://geekandsundry.com/dice-shaming-a-fantastic-source-of-mirth-through-misery/

This comes up so often on roll20.  I love your reply Andreas.  That really needs to be stickied somewhere.


November 28 (5 years ago)
Steve
Marketplace Creator

Hhahah well all I can say is then I would prefer the program to mimic real dice rather than being "true random". I want a session's rolls to feel like we're at a table (we've been RPing for 30 years on and off), and the dice just don't feel right. I know, I know - "feel" right. But it's a real thing. And the number of complainants about the randomness suggest many people are seeing this weird distribution effect. When we played using Fantasy Grounds, we didnt get this feeling of weirdness from the dice. There's something in that. I dont know how to explain it, or fix it, but the roll20 guys should take another look at the distributions happening over short periods.

November 28 (5 years ago)

Edited November 28 (5 years ago)
keithcurtis
Forum Champion
Marketplace Creator
API Scripter

The "many complaints" are usually from folks who conflate "random" with "evenly distributed". Assuming you have a reasonably well-constructed set of dice, it would be impossible to tell from a string of numbers wether they were generated by dice or the online system. I have been a real life tables and witnessed 5 natural 20s rolled in the course of 7 rolls. Flukes happen. But no one notices when you roll 4 natural 15s in a short span. We see patterns, particularly patterns that have meaning for us.


In short, I'm not sure I understand what you are asking the dice system to do. "True random" does "mimic real dice".

November 28 (5 years ago)

Edited November 28 (5 years ago)
Ziechael
Forum Champion
Sheet Author
API Scripter

I'd say that the feeling of 'off' dice for me comes from the semi-permanence of the rolls. I roll bad... consistently... with both physical and digital dice, with digital ones however I can go back through the chat log and see my horrific luck, that makes it very real and patterns of poor rolls stand out like a sore thumb. With physical dice I 'remember' having a run of bad rolls but only the truly monumental f-ups stick in my memory for long enough to form patterns.

I've found, through long years of using Roll20 for regular sessions, that some sessions just suck (which is the same as at the table in my 30+ years of experience too)... your only hope is to sacrifice a digital goat to the digital dice Gods and hope they heed your calls. That, or you could start each session by having every player put [[999d20]] into the chat to get rid of the first ~1000 rolls, that would get you out of any potential short period bias ;)

November 28 (5 years ago)
keithcurtis
Forum Champion
Marketplace Creator
API Scripter

You could also roll the physical dice of your choice and use the honor system, but you would be giving up a lot of convenience for an illusory gain.

November 29 (5 years ago)
Stephanie B.
Forum Champion
Sheet Author

Oh, Steve, I feel your pain. I've had entire campaigns where I couldn't roll above a 6 on a d20, unless it was against a fellow PC. The dice in Roll20 are more random than physical dice, but it does hurt when the bad luck runs against you in a single session.

As a suggestion, have you used the 3-D dice? There's something a little more satisfying about clicking and dragging to roll the dice that can feel like they're real dice. There are limits, though-- don't try to roll a bucket full of 3-d dice, for example. But for your normal roll of 1-5 dice, I've found them to be pretty solid, and they can give that satisfying "feel" of rolling dice.

Steve said:

Hhahah well all I can say is then I would prefer the program to mimic real dice rather than being "true random". I want a session's rolls to feel like we're at a table (we've been RPing for 30 years on and off), and the dice just don't feel right. I know, I know - "feel" right. But it's a real thing. And the number of complainants about the randomness suggest many people are seeing this weird distribution effect. When we played using Fantasy Grounds, we didnt get this feeling of weirdness from the dice. There's something in that. I dont know how to explain it, or fix it, but the roll20 guys should take another look at the distributions happening over short periods.