Concentration

To cast a spell, you must concentrate. If something interrupts your concentration while you're casting, you must make a concentration check or lose the spell. When you make a concentration check, you roll d20 and add your caster level and the ability score modifier used to determine bonus spells of the same type. Clerics, druids, inquisitors and rangers add their Wisdom modifier. Bards, paladins, and sorcerers add their Charisma modifier. Finally, magi and wizards add their Intelligence modifier. The more distracting the interruption and the higher the level of the spell you are trying to cast, the higher the DC. If you fail the check, you lose the spell just as if you had cast it to no effect. (see Magic)