Core Outcome Set

Core outcome sets (COS) are standardised sets of outcomes that researchers agree should be measured and reported in all clinical trials for a specific condition (e.g. asthma) or specific context (e.g. community-based trials).  

Core outcome sets ensure that all trials on a particular condition measure and report the same key outcomes. This allows us to bring together and compare the findings of many trials to provide us with a stronger evidence base. It also improves the transparency of trial reporting, ensuring we have a comprehensive understanding of the trial results. COS are developed through a consensus process involving various stakeholders, including doctors, patients, researchers, and policymakers. This process typically involves exploring what outcomes have been previously reported in the literature and what outcomes are deemed important by stakeholders, before using a consensus process to identify the most important or ‘core’ outcomes. Involving stakeholders in this process also ensures that trials measure the outcomes that really matter to patients and healthcare providers. Core outcome sets therefore help improve the quality, relevance, and usability of clinical research, ultimately leading to better healthcare decisions and outcomes for patients.