The genesis of the dice system was driven out of simplicity as well as a desire to draw more out of a dice roll than just a high/low number or margin of success.
The premise is: however many dice are rolled, three dice are chosen and if the result is 11+, the result is success.
For everything in your favor, one additional bonus die is rolled.
For everything against you, one additional penalty die is rolled.
Bonus and penalty dice cancel out, the remainder is added to three base dice for you to roll. If penalty dice remained, pick the lowest three dice. If bonus dice remained, pick the best three dice.
Best, you say? Yes, best. Doubles and triples can generate stunt points which power special abilities, powers, and more.
If you want to know more, I invite you to read The Basics (p. 2-3) in the Core Rules.
Now, it turns out that the math is more involved that simple 3d6 probability. I love this part of it. As we’ve played this at conventions over the years many players have questioned the choices and the value of skill ranks and talents. It is to those questions that I share not only the NOVA6 Probability Table, but an amazing combinatorics analysis of the system by a professional mathematician: Johnathan Napier.
The table provides the probabilities for Failure, Success, Doubles and Triples.
It also provides the probability for getting 1 Stunt Point (Standard) as well as 2 Stunt Points (if the skill is Focused).
I have been looking forward to sharing this analysis because I enjoy the way the system plays, and the fact that the math supports my original intent is IMO fantastic. If you love math, and you want a deep dive, then please download Johnathan Napier’s analysis.