>>15997310Think of it as a locked value for every stat. It ranges from 0 to 31 and determines how many extra points your Pokemon will have in that stat. A Pokemon with 31 HP IVs will have the maximum HP at lv. 100, for its base stat, that is, while a Pokemon with any other won't have as much HP. This is without counting the 63 possible points from EV training.
Basically what you want to do is try to get IVs for your Pokemon's most important stats. Defensive Pokemon want perfect HP and defenses while offensive Pokemon want perfect Attack, Sp. Atk. and Speed. Since there's no way not to benefit from 31 IVs, most players tend to aim for a "perfect" Pokemon, with 31 in all of its stats.
