Patient-reported outcomes (PRO) report the status of a health condition directly from the patient, without any interpretation by clinicians or anyone else. Put simply, PROs offer insights that only patients can themselves provide. They capture functional status, symptom burden, or quality of life that cannot be fully assessed through physical examination, clinical observation, or diagnostic testing. While surgeon-reported outcomes have long been central in clinical research, PROs are increasingly valued as they contribute significantly to patient-centered care and the evaluation of effectiveness of an intervention. Understanding PROs is essential for surgeons who aim to assess outcomes meaningful to their patients. This chapter covers the essential aspects of patient-reported outcome measures (PROMs), explaining their development. Through a clinical scenario, we outline the steps for critically evaluating a PROM that is commonly referenced in the surgical literature. Additionally, for surgeon-investigators, this chapter details the foundational steps in developing a novel PROM, from concept to implementation.