Current Controlled Trials (CCT) has introduced digital object identifiers (DOIs) to all ISRCTN records. DOIs issued by the organisation CrossRef are unique alphanumeric ID assigned to a digital object, such as an electronic journal, article, report, thesis or a clinical trial record. A DOI serves as a stable, persistent link to the full-text of an electronic item on the internet. The journal or article website address can change over time but a DOI is permanent. DOIs are widely used by academic publishers for helping to ensure the permanence, discoverability and citability of scholarly content published on the web.

A trial ID such as the ISRCTN uniquely identifies a clinical trial. Introduction of a DOI (made up of the ISRCTN 8 digits – see example) will ensure that the web link to the trial ID can persistently be discovered and cited. Implementation of a DOI system is a vital step for the threaded publications initiative which puts trial registration with clinical trial registers such as the ISRCTN register at the top of transparent reporting. DOIs for ISRCTN records will ensure that all publications and outcomes of a clinical trial are disseminated in a linked and threaded fashion.

Benefits for trialists registering with CCT and receiving a DOI include:
• Even more confidence that the link to the trial record (or information about the record) will be persistently and uniquely identified
• Increased ease of citing trial records which will, in turn, increase its discovery and access, enabling others to verify the results and validate their own research
• More potential for acknowledgement and credit for trial registration and having the record cited
• Potential for more consistent linking of trial records to resulting publications

For more information on how to cite an ISRCTN trial record, please read the guidance notes.