Shared decision making (SDM) occurs when patients and clinicians collaboratively make medical decisions that align with a patient’s values and preferences. It is a core component of the patient-centered medical home. It is especially important for adolescents with chronic conditions and their parents or guardians (hereafter parents) given the frequent need for medical decisions among these patients and their families. Yet, there is a critical gap: no SDM measure has been developed to measure adolescent SDM (aSDM). Without a reliable and valid measure of aSDM, it is impossible to evaluate the extent to which: aSDM has occurred, aSDM impacts outcomes, or interventions designed to facilitate aSDM are successful. In alignment with PA-16-424 (Developing Measures of Shared Decision Making), our objective is to create the first SDM measure to explicitly incorporate the pediatric patient’s role in aSDM and measure their perspective. An SDM measure developed specifically for use with adolescent patients is needed because SDM with adolescents is fundamentally different than SDM with adult patients or with parents of younger children. Unlike most SDM, which occurs between two individuals (the adult patient or young patient’s parent and the clinician), aSDM with adolescents occurs among at least three people (the adolescent patient, their parent, and the clinician). Thus, our measure will explicitly evaluate, from the patient’s and parent’s perspectives separately, the extent to which each of these three individuals engages in aSDM. To develop our measure of aSDM, we will employ PROMIS measure development methods. These methods have never been used to develop and validate any SDM measure. Our specific aims are to: Aim 1: Refine the dimensions of aSDM from adolescent, parent, and pediatric clinician perspectives. Aim 2: Develop a measure of aSDM that incorporates aspects of the decision triad (adolescent, parent, clinician) and separately measures aSDM from the adolescent and parent perspectives. Aim 3: Demonstrate the aSDM measure’s reliability, validity, acceptability, and ability to feasibly measure SDM in clinical settings. We will conduct qualitative interviews with adolescents with chronic conditions, parents of adolescents with chronic conditions, and clinicians who care for adolescents to refine the dimensions of aSDM. We will demonstrate the measure’s reliability, validity, feasibility, and acceptability in a sample of 500 adolescents with chronic conditions and 500 parents. The expected outcome of our proposal is a reliable and valid measure of aSDM that is feasible for use in clinical settings for research, quality improvement, and performance measurement. Our proposal is innovative because 1) it will be the first SDM measure developed specifically for adolescents and 2) the first study to apply PROMIS standards to the development of any SDM measure. Our proposal directly addresses multiple AHRQ priority populations: children, adolescents, and indi...