This term is generally used to refer to a study that had not been published in a biomedical journal. As awareness of the utility of the range of types of clinical study data has grown in the last decade, from publications to data such as clinical study reports, individual participant data, and drug approval packages, the term “unpublished study” has become more ambiguous and consequently more confusing.  This is because a study may not be published in a biomedical journal, but still it may have a clinical study report that is more than 1000 pages long and there may be methods and results data from this trial recorded in trial registers. On the flip side, “published studies” may have journal publications associated with them, but study documents like the trial protocol and results reporting to a trial registry may be absent.  The take-home message is that “unpublished data” and “unpublished study” are two distinct concepts.

Now, does results reporting on trial registers (like ClinicalTrials.gov) constitute publication?  If we accept that the root of the word “publish” means “to make public”, a registry entry (with results), a clinical study report released by a regulator or a sponsor, a report posted on the web, a regulatory review containing sufficient information and a researcher’s report made public could fulfil the requirement for publication. However in the context of a trial, the term “report” usually means a document with an IMRAD structure, and therefore contains more than just methods and results data, but also contextual data found in the Introduction and Discussion section of a manuscript. So regulatory reviews (like a FDA medical officer report) and register entries do not fulfil the definition of report. At the RIAT Support Center, we believe that the terms “invisible” and “published in….” describe the current situation more accurately.