It is the position of the National Association of School Nurses (NASN) that schools should employ professionally prepared Registered Nurses, to conduct and supervise school health programs which address the variety of health problems experienced by school children. NASN recommends a formula-based approach with minimum ratios of nurses-to-students depending on the needs of the student populations as follows: 1:750 for students in the general population, 1:225 in the student populations requiring daily professional school nursing services or interventions, 1:125 in student populations with complex health care needs, and 1:1 may be necessary for individual students who require daily and continuous professional nursing services. Other factors that should be considered in the formula-based approach are number of students on free or reduced lunch, number of students with a medical home, and average number of emergency services per year.