Use of outcome measures in physical therapy practice is central to evaluating the effectiveness of treatment interventions, providing accountability and addressing quality of physical therapy programs. There is limited discussion on barriers and facilitators to using outcome measures in physical therapy practice. The purpose of this study was to identify factors that influence a physical therapist when deciding to use outcome measures in clinical practice. Participants were 21 physical therapists, seven each from skilled nursing facilities, outpatient clinics, and inpatient rehabilitation facilities. A grounded theory approach was used for interview and data collection. Common themes were determined from the data and a theory developed to explain the rationale behind physical therapists' decisions to use or not use outcome measures in clinical practice. Three overlapping themes related to 1) concepts of time, 2) knowledge, and 3) facility culture were indentified as factors influencing the use of outcome measures. A fourth encompassing theme, professionalism, identified the value placed on the use of outcome measures in practice. Data revealed that therapists require more information on the outcome measures available, and this information needs to be easily accessible within the workplace. Therapists value information generated by using outcome measures in the clinical setting, but need information on what measures are available and psychometric properties. Information must be easily accessible and measures easy to use. Newer graduates and recent learners have a foundation in the use of outcome measures, but more needs to be done in the clinic and through continuing education to promote increased use and understanding. © 2012 Informa Healthcare USA, Inc.