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>
...

Using @content-type

When tagging links to clinical trials, some suggested values for the @content-type attribute (on <related-object>) include:
  • “pre-result”
  • “result”
  • “post-result”

Using @source-id

When tagging links to clinical trials, some suggested values for the @source-id (on <related-object>) include:
  • “ANZCTR”
  • “ChiCTR”
  • “ClinicalTrials”
  • “CRiS”
  • “CTRI”
  • “DRKS”
  • “EU-CTR”
  • “IRCT”
  • “ISRCTN”
  • “PACTR”
  • “ReBec”
  • “RPCEC”
  • “SLCTR”
  • “UMIN-CTR”

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>

Journal Archiving and Interchange Tag Library NISO JATS Version 1.2 (ANSI/NISO Z39.96-2019)

Version of May 2019

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