A derived trait is a trait which is determined by the values of other traits. Derived traits may be calculated by adding two other traits together, by determining the lowest or highest rating from a pair of traits, or occasionally by other means.
A very small number of derived traits were used in the Storyteller and Revised Storyteller systems, though usually only the initial values of traits were derived from others; after character creation, these traits' values are independent of the traits used for the initial calculation. For example, in Vampire: The Masquerade, a vampire's Willpower was initially the value of the Virtue trait Courage (while Humanity was the combined value of Conscience and Self Control), but additional Willpower dots could be bought using Freebie points and the character's Willpower score could increase (or, rarely, decrease) independently of the Virtue traits.
In the Storytelling System several traits are always derived from other traits. Several of these are expressed numerically rather than by using dots, including Speed and Initiative. Health and Willpower are also permanently derived traits - their values always depend on other traits. Health may temporarily increase from its derived value, usually by supernatural means, but generally returns to its normal value. Willpower may drop below its derived value but never rise above it.