Tagging Links to Clinical Trial Descriptions
“Tagging” Clinical Trials in JATS means tagging external links to clinical trial descriptions that identify the Clinical Trial registry and have a Crossref or other identifier for the trial. Clinical trial registration information from https://clinicaltrials.gov/ is typically displayed as a simple link plus the registration number, e.g.:
Trial registration: NCT02442440 (https://register.clinicaltrials.gov/)
In JATS tagging, there are two convenient ways to encode this information: as a simple <ext-link> or as a more complex link using an <related-object> element.
As an External Link
When a clinical trial link is just a typical link to a known resource, the <ext-link> element can be used to good effect. The identifier and the resource information are supplied in the attributes, and the element content is the link display text. For example:
... <p>... Trial registration: <ext-link ext-link-type="clinical trials" xlink:href="NCT02442440">NCT02442440</ext-link> (<ext-link ext-link-type="uri" xlink:href="https://register.clinicaltrials.gov" >https://register.clinicaltrials.gov</ext-link>) ... </p> ...
As a Related Object
There are also cases where it is useful to provide more metadata (for instance, a clinical trial title or a DOI) and a stronger association between an article and a clinical trial than a mere <ext-link>. For these cases, the <related-object> element is a better fit to purpose:
... <related-object link-type="clinical-trials-registry" content-type="pre-result" source-type="clinical-trials-registry" source-id-type="ISRCTN" source-id="ISRCTN69423238" xlink:href="http://dx.doi.org/10.1186/ISRCTN69423238"> <source>Spontaneous Urinary Stone Passage Enabled by Drugs</source> </related-object> ...
Crossref Trial Encoding (July 2017)
Below is a draft of the XML that Crossref is expected to accept regarding clinical trial encoding. The <related-object> encoding just illustrated includes all of the information needed to create this Crossref record:
<ct:program> <ct:clinical-trial-number registry="10.1186/ISRCTN69423238" type="pre-result" >ISRCTN69423238</ct:clinical-trial-number> </ct:program>