S.P.E.C.I.A.L. is the name of Fallout 3's character statistics system. Each letter stands for a particular stat and directly influences the player's available skills and perks.

1. Strength - Physical strength, amount of dmg, hit chance, hit points, amount carried
2. Perception - Chance to hit with firearms, find landmines/traps
3. Endurance - Poison/radiation resistance, regen rate, hit points gained when leveling up
4. Charisma - Discount/barter prices, NPC reactions
5. Intelligence - Skill points gained when leveling up, dialog options
6. Agility - Action points, armor class, sneak successPlanet Fallout: Fallout 3 SPECIAL
7. Luck - Critical hits, each point adds 1% to all skillsFallout Wikia: Luck

In Fallout 3, there are three sets of character traits to keep track of: S.P.E.C.I.A.L. statistics, skills and perks. S.P.E.C.I.A.L. statistics are the foundation of the character's abilities and are measured on a scale from 1 to 10. They determine how well he uses selected skills and which perks he can access. With the exception of perhaps Luck and Perception, they will be familiar to most fans of role-playing games.

Every skill in the game is associated with a S.P.E.C.I.A.L. stat. For example, a person choosing to concentrate on leveling up his Medicine skill would do well to roll a character with high Intelligence. Additionally, some perks are only available to characters with certain stats. An example of this is the Action Boy perk, which requires an Agility level of 6.Fallout Wikia: Fallout 3 Perks Each statistics point raises its corresponding skill by 2%.Fallout Wikia: Luck