What registries and registrants can do to facilitate unambiguous identification
If a trial involves a single site, it should not be necessary to register that trial more than once.
If a trial involves more than one site in a single country, it should not be necessary to register that trial more than once.
If a trial involves sites in more than one country, it is possible that the trial will need to be registered more than once in order to meet the ethical, legal or other requirements of each country. If this is the case then it is recommended that:
- Each trial should have a single point of contact for the trial as a whole, regardless of the countries in which the trial is being conducted. That person should be responsible for the trial registration data set and for making sure that the same data is provided to each registry.
- Within each country, before registering the trial, the person who is considering submitting the trial to a registry should first determine if the trial has already been registered on any Primary Registry or ICMJE approved registry.
- When a trial is re-registered, all known identifiers for the trial should be submitted. These include trial registration numbers allocated by other registries.
- Trials should only be included on more than one registry if it is absolutely necessary.