Many policymakers and clinicians have argued that expanding the number and utilization of nurse practitioners (NPs) is an important strategy to meet future growth in the demand for health care services in the United States. State scope-of-practice (SOP) regulations, which govern the breadth of services that NPs can independently provide, affect the supply of NPs and their effectiveness in meeting patients' care needs. NPs in Michigan have no defined SOP and currently function under the SOP of registered nurses, which limits their ability to practice and prescribe.