Appropriate staffing in the outpatient oncology setting contributes to the delivery of quality care. Objective measures of acuity and nursing workload can assist with developing staffing models; however, measuring acuity in an early phase clinical trial outpatient setting can be challenging. Treatment nurses in this setting perceived that the patient acuity tool (PAT) did not accurately capture the high variance in patient complexity, which led to inequitable workload distribution. Nursing leadership, in collaboration with treatment nurses, updated the existing PAT. Enhancing the PAT led to nursing assignments based on objective acuity, rather than traditional volume- based or subjective variables. A growth formula algorithm provided quantifiable data to justify three additional treatment nurse positions, even as average patient volume remained stable.