Missing documents in Scopus: the case of the journal Enfermeria Nefrologica

In a recent paper, a group of researchers estimated various bibliometric indicators for the Spanish journal Enfermeria Nefrologica using the software “Publish or Perish”, retrieving data exclusively from Google Scholar. Since their study revealed an unusual high number of citations for the documents published by the journal, we became interested in repeating the bibliometric analysis using data from Scopus. Surprisingly, our analysis revealed a high variability in the number of documents published each year. Therefore, the journal’s website was accessed to confirm whether this irregularity was due to the journal’s publication frequency. According to the data collected, only 50.2% of the documents published by the journal between 2006 and 2017 were registered by Scopus. Such omission-induced errors raise concerns about the validity of various indicators. This study shows that while Scopus needs to improve its quality control systems, editorial management teams need to routinely check the information being indexed by the databases.