The NHS routinely evaluates the quality of life of patients receiving hip or knee replacement surgery using patient-reported outcome measures (PROMs), but some hospital completion rates are only 30%, restricting data usefulness. Statistics limit insights into how and why data are missing, so qualitative methods were used to explore this issue. Observation periods preceded semistructured interviews with 34 preoperative patients attending an orthopedic outpatient clinic. Interview themes covered: completion time/timing, orientation, setting, measures, and practicalities. Triangulated against observations, pragmatic barriers, and facilitators were considered. Refined themes included completion conditions, patient support, and national delivery. Simple improvements (e.g., quiet zone) could improve completion rates and reducing missing data. Reorganizing preoperative leaflets and their systematic distribution via standardized procedures could reassure patients, enhancing PROMs acceptance, while reducing inquiries and subsequent staff burden. Findings have implications for interpreting national statistics. They indicate that further debate about mandating preoperative PROMs is due.