When the patient does visit the doctor, they increasingly are asked questions to elicit information about symptoms and performance using structured questionnaires that are shown to give reproducible, meaningful, quantitative assessments of how patients feel and how they function—measures that are called patient reported outcomes or PROs. The questionnaires used to collect this information are called PRO instruments. The use of PRO instruments is part of a general movement toward the idea that the patient, properly queried, is the best source of information about how he or she feels. The goal of using PRO measures is to provide better information to doctors and patients so that the best treatment for patients can be determined.