A system for assisting a rescuer with treatment of a patient is described. An example system includes a mobile computing device that includes a user interface and a processor coupled to memory. The processor is configured to cause the user interface to prompt the rescuer to select a proficiency level from among multiple proficiency levels including a basic proficiency level and at least one non-basic proficiency level. The basic proficiency level includes basic resuscitation instructions for the rescuer. The system is further configured to receive an input from the rescuer of the selected proficiency level. The system provides, if the rescuer selects the basic proficiency level, the basic resuscitation instructions to the rescuer, and provides, if the rescuer selects the at least one non-basic proficiency level, non-basic instructions to the rescuer. The system transmits signals to control a defibrillator according to the selected proficiency level.