Beyond regulatory compliance: strengthening reporting quality and transparency in ClinicalTrials.gov

ClinicalTrials.gov is the world’s largest clinical trial registry and a cornerstone of transparency in research involving human beings. Since its launch in 2000, the registry has undergone several regulatory and technical updates. However, important challenges remain regarding data quality, usability and adherence to international reporting standards. In this article we critically assessed the current content and structure of ClinicalTrials.gov and identified areas where targeted modifications and further developments beyond regulatory requirements could improve reporting quality, transparency, and usability for key stakeholders. We conducted a critical review of the current version of ClinicalTrials.gov. We examined the different sections of the registry in light of relevant meta-research and methodological literature, including the SPIRIT 2025 and CONSORT 2025 statements. We sought to identify limitations in the registry’s content and structure and formulate pragmatic recommendations for improvement. We identified six major domains in which ClinicalTrials.gov could be strengthened: (1) study identification data, including a clearer characterisation of the connections between trials and researchers; (2) methodological data, including the creation of new dedicated sections, improved structuring of eligibility criteria and outcome measures, as well as the ability to pre-specify the statistical methods; (3) trial results, through more detailed reporting of participant flow and an explicit description of causes of death; (4) search engine, including the option to search by any eligibility criterion; (5) patient-centred features, through the creation of a specific section explaining what participation in the trial entails; and (6) transparency and quality indicators, summarised in a dashboard presenting key information with visual flags. We propose several approaches to improve ClinicalTrials.gov, including structural changes to the way data are captured and to the website interface. These improvements could increase the registry’s utility for patients, researchers and policymakers, thereby strengthening transparency and accountability in clinical research.