IQ

IQ is a stat in the Mother series, short for intelligence quotient. Its effect is not entirely clear, as it is not described in-game. However, in EarthBound, IQ increases the amount of PP the user has, an IQ point is equivalent to 5 PP, also, Jeff Andonuts' IQ affects his ability to fix broken items. Also, some PSI, such as Brainshock, can be affected by the IQ level of the attack target.

In the Mother 3 hidden memo menu (found by holding the L and R buttons while entering the status menu) available in the fan translation patch, it is explained that "If a character is able to use PSI, a higher IQ will increase its effectiveness."