Attack, defense (and their Special counterparts) and Speed can either be increased up to 6 stages, in .5 increments ( i.e 1.5x, 3x etc...) or decreased up to 6 stages which is the inverse of the increase such as 1/1.5 = .67 or 1/4 = .25. This makes the cap for decrease 0.25x and increase at 4x...