Rules have changed a bit since the days of Original and Advanced Dungeons and Dragons but the core six stats passed down to us from Lord Gygax ... these will never change ... Well ... the order has changed ... and the way they are generated has changed a bit ... but the core stats are the same.
Starting in third edition the core stats were rearranged as Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. The new order has a certain logic behind it; physical stats in front, mental stats in back. The way of generating stats was to roll four six sided dice and sum the three highest rolls. The 3d6 method gave an average of 10.5 while the new method provides a mean of 12.42 and a median of thirteen. Both methods have a highest score of 18 and a lowest score of 3 and all of the stats provide bonuses in the same general fashion. See, each score provides an ability modifier which is the number we really care about. You may ask why we have the first number at all ... The modifier is your score divided by two minus five and rounded down where applicable. This provides a modifier of zero at ten and eleven, four at eighteen, and negative two at seven. Stats are often abbreviated as their first three letters. Now that we've established how they work let's look at what the individual attributes do.
STRENGTH is exactly what it sounds like and has the main function of increasing the chance of hitting and the damage done in melee combat. Apart from that it governs athletic pursuits like swimming, climbing, and jumping. This is the most improtant stat for the front liner with the sword, axe, maces, or spear.
DEXTERITY covers hand-eye coordination, agility, and reflexes. It can add to armor class, chance of hitting at range, reflex save, and a ton of skills. It's arguably the most valuable stat though not to the point that a high dex character can dominate a campaign.
CONSTITUTION affects the number of hit points a character receives every level and fortitude saves, which protect against toxins and the like. It the most important to martial classes but every class benefits significantly from having high constitution.
INTELLIGENCE is essentially reasoning and memory. It modifies how many skill points you gain in third edition and is the core casting stats for Wizards in all editions. It's also the stat for knowledge rolls.
WISDOM is a combination of will power and perception stat, neither of which are synonyms for wisdom but whatever. It's the casting stat for clerics, druids, paladins, rangers, and warlocks as well as modifier for will saves. Rolls to notice detail in the environment and the healing/medicine skill are both based on this as well.
CHARISMA is the social stat. It covers all attempts to persuade, deceive, and intimidate. Unlike nearly every other stat in the game the usefulness of this one varies a lot depending on the Dungeon Master and how much talking features in the campaign. For this reason it's a dump stat for most martial classes and wizards.
"But wait, how does any of this work in practice?" you may ask. Okay, example time. for the sake of simplicity I'll say up front that the difficulty class aka the number you need to reach or exceed is always ten.
Bob is the dungeon keeper for King Charlie. He maintains the vast, trap filled labyrinths under the castle. Bob has the following stats Str 15, Dex 13, Con 11, Int 9, Wis 8, and Cha 7. Bob fell through a trap door that he usually walks past and ended up in a lower and more dangerous part of the dungeon. He thinks he knows where he is and how to get back to the surface. He starts back only to encounter the first obstacle, a twenty foot deep pit full of spikes. The pit is a mere ten feet wide and Bob feels pretty confident he can make the jump with a running start. He backs down the hall, sprints toward the pit and the guy playing Bob rolls a d20. The die lands on a nine but Bob has 15 Strength which gives him +2 on athletics rolls bringing his total up to eleven. Bob times the jump right and sails over the pit. He brushes himself off and moves forward making sure not to step on the left flag stone which will trigger the dart trap. He hears a click from the floor as it occurs to him that it's only the left flag stone if you are coming from the other direction. A roll of the d20 lands on a six which is a seven after adding his Dex modifier. This is still less than the requisite ten and a poison dart lands in his side before he even thinks to dodge. A third d20 is rolled to decide whether or not the darts poison knocks him out. The die lands on a seventeen and since his Con modifier is zero his roll isn't modified. That is more than ten so he remains conscious. He's going to have to be more careful. The player asks if there are any more traps on the way back and the Dungeon Master rolls a memory test in secret, subtracting one from the roll because of his low Int score and tells the player Bob doesn't remember any more traps. Bob wanders back through the labyrinth and eventually makes it back to the dungeons entrance which is sealed by a strong iron door. He reaches for his key ring only to discover that it's missing. Bob is forced to bang on the door until the castle guard Alice shows up. Alice is superstitious enough to be worried that what's speaking to her is actually some sort of spooky monster that ate the real dungeon keeper and demands some sort of proof that Bob is who he says he is. The player makes a persuasion roll that lands on an eleven which would be enough except Bob's Cha modifier is -2 which brings him down to a nine. Bob is literally so creepy he can't convince Alice that he's human and she leaves to get a priest and several more guards.
IRON NODER X: XTREME XCELLENCE