Availability of digital object identifiers in publications archived by PubMed

International audienceDigital object identifiers (DOIs) were launched in 1997 to facilitate the long-term access and identification of objects in digital environments. The objective of thepresent investigation is to assess the DOI availability of articles in biomedical journalsindexed in the PubMed database and to complete this investigation with a geographicalanalysis of journals by the country of publisher. Articles were randomly selected fromPubMed using their PubMed identifier and were downloaded from and processed throughdeveloped Hypertext Preprocessor language scripts. The first part of the analysis focuseson the period 1966–2015 (50 years). Of the 496,665 articles studied over this period,201,055 have DOIs (40.48%). Results showed that the percentage of articles with DOIsbegan to increase for articles published in the 2000s, with spectacular growth in the years2002–2003, then reached a peak in 2015. Data on countries showed that some countriesgradually implemented DOIs over the period 1966 to 2015 (the United States, the UnitedKingdom, and the Netherlands), while some did not (Russia, the Czech Republic, andRomania). The second part of the analysis focuses on the year 2015 and includes 268,790articles published in 2015, randomly selected to evaluate the current implementation ofDOIs. In 2015, 86.42% of articles had DOIs. The geographical analysis of countries ofpublishers showed that some countries (Russia, Thailand, and Ukraine) still assigned fewDOIs to articles in 2015. Thus, if the scientific community aims to increase the number andthe usefulness of services rendered by DOIs, efforts must be made to generalize their useby all persons involved in scientific publication, particularly publishers