This article describes how one very large, diverse school district developed a Student Acuity Tool for School Nurse Assignment and used a logic model to successfully advocate for additional school nurse positions. The logic model included three student outcomes that were evaluated: provide medications and procedures safely and accurately, increase the number of students with a medical home, and increase the number of students with chronic illness that receive case management. Pairing a staffing formula with an evaluation plan that focuses on student outcomes and the priorities of the school district provides a strong case that school nurses are essential and that they contribute to student success.