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2008 MARCH–APRIL No. 361
March 10, 2008 [posted]

Study Collaborators Included in MEDLINE®/PubMed®

nLM® has noticed a trend in recent years toward the increasing occurrence of group authors as the sole author or as co-authors for published articles. There are also consortia composed of several groups that publish scientific research articles. As of November 2007, there were over 57,000 occurrences of group (corporate) authors in MEDLINE/PubMed with over 17,000 citations with no co-occurring personal authors.

Not everyone involved in a group is actually writing or authoring the paper, however. NLM agrees with organizations such as the International Committee of Medical Journal Editors (ICMJE) and the Council of Science Editors that "Authorship credit should be based on 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it critically for important intellectual content; and 3) final approval of the version to be published. Authors should meet conditions 1, 2, and 3."1

Taking these and other factors into consideration, NLM decided that it is time to include the individual names associated with the group authors in MEDLINE/PubMed. Therefore, when a group name is included as an author, the respective group member names appearing in the article will be acknowledged as collaborators but not associated with authorship. This significant enhancement allows PubMed users to identify articles to which an individual has contributed, whether as an author or as a collaborator. NLM has implemented this new feature routinely for MEDLINE citations created beginning in March 2008 if the article was published in 2008 forward.

Changes to PubMed's Displays

Records that include collaborator names have a "Collaborators" link on the Abstract, AbstractPlus, and Citation displays (see Figure 1). The number of names will be shown in parentheses.

Clicking on the link will display the names of members of the group(s) found in the collaborator list. Some author names may be repeated as collaborators. And while there may be multiple groups as co-authors on a citation, there will be a single, combined list of collaborators. As with author names, the name of each collaborator serves as a search link in PubMed (see Figure 2). To close the list, click on the Collaborators link.

On the MEDLINE display format the names of collaborators appear in two fields: Investigator (IR) and Full Investigator Name (FIR). Names of NASA-funded investigators which were at one time added to MEDLINE records work in the same way as collaborators.

Changes to PubMed Searching

PubMed's Automatic Term Mapping has been revised so that a name entered using either the lastname+initials format (e.g., smith ja) or the full name format (john a smith) and no search tag is searched as author as well as collaborator depending on what exists in the database. To search just for collaborators, use either the [ir] or [fir] search tags. To search for just personal authors, use the [au] or [fau] search tags, or use the author search option in Limits or the Single Citation Matcher. For group author names, use the [cn] search tag. The Preview/Index screen can be used to browse for Author, Full Author Name, Investigator, Full Investigator Name, and Corporate Name. For more information about searching, see PubMed's [link removed] Help.

For additional information see Order of Authors in MEDLINE®/PubMed® Citations.

1International Committee of Medical Journal Editors. Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Writing and Editing for Biomedical Publication [homepage on the Internet]. Philadelphia, PA: The Committee; [updated 2007 Oct; cited 2008 Mar 10]. Section II.A.1 Byline Authors. Available from:

By Lou Wave S. Knecht
Bibliographic Services Division
Annette M. Nahin
MEDLARS Management Section

Knecht LS, Nahin AM. Study Collaborators Included in MEDLINE®/PubMed®. NLM Tech Bull. 2008 Mar-Apr; (361):e2.

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