This review describes that a core outcome set (COS) represents a consensus-based minimum set of outcomes to be collected and reported in clinical trials involving a particular disease or population. A COS serves as a guideline for global consensus on which outcome domains should be collected in all clinical trials. After defining what to measure, it becomes crucial to reach consensus on how to measure it. This includes the selection of appropriate outcome measurement instruments with credible measurement properties and interpretable thresholds of meaning.
Published under Open Access CC-BY-NC-BD 4.0. https://creativecommons.org/licenses/by-nc-nd/4.0/.