This chapter explores the taxonomy and categorization of patient-reported outcome measures (PROMs) and experience measures (PREMs) to assess various dimensions of health, quality of care, and innovation in healthcare systems. The taxonomy covers six key domains: quality of life, individual care, community, care provided, provider culture, and innovation. PROMs focus on health status, self-care, and community factors, while PREMs assess service quality, organizational culture, and the impact of innovations. Grouping PROMs and PREMs into core outcome sets (COS) addresses the growing complexity of outcome measurement and the need for standardized evaluation frameworks. Option sets with consistent response formats enable meaningful data collection while minimizing ceiling and floor effects. This chapter supports healthcare professionals in tailoring measures to diverse needs (for personalized care, quality improvement, or clinical trials) by providing clear definitions and categorization. This approach ensures comprehensive assessments that drive better outcomes, improved patient experience, and more effective healthcare delivery.