Derived statistics

Derived statistics or secondary statistics in the strict sense are attributes of a character in the SPECIAL system which are based on (or derived from) the character's primary statistics. More commonly, the term refers to all character attributes which only exist as a function of another value, i.e. character attributes which the player cannot determine or influence directly.

Altering

Most derived statistics are directly based on a primary statistic, but may also be altered independently, for example by perks and traits. Carry Weight, for instance, is directly based on Strength, but can be increased by the Pack Rat and Strong Back perks. Action Points are based on Agility, but are lowered by Bruiser trait for example.