“Some time ago, Archivos de Bronconeumología reported on a radical turnabout by the ICMJE: after announcing in 2016 that they would require clinical trial researchers to share individual-level anonymized participant data with third parties, in 2017 they decided that such transfer would be voluntary.4 The news had a precedent in the Recommendations published a few years earlier, to the effect that some journal editors “ask authors to say whether the study data are available to third parties to view and/or use/reanalyze, while still others encourage or require authors to share their data with others for review or reanalysis”.1 It would be interesting to know which Spanish journals have included this requirement in their ‘instructions for authors’ and whether they comply with it.

To answer this question, we reviewed the portals of 24 Spanish journals with an impact factor greater than 1, on the understanding that they have greater influence than those with an impact factor ?1 and those with no impact factor. Of these 24, 14 are included in the list of ICMJE Recommendations (Supplementary material A). Of these, only 5 (Archivos of Bronconeumología, Atención Primaria, Enfermedades Infecciosas y Microbiología Clínica, Gaceta Sanitaria, and Medicina Intensiva) include a specific section, that we shall call “link to data repository”, that recommends, supports and encourages authors to share raw data from their studies with other researchers, and gives instructions on how to go about it. A sixth journal, the Revista de Neurología, recommends this procedure only for clinical trials (Supplementary material B). To determine the frequency with which authors report how data can be accessed compared to other requirements requested by the same journals, 2 control requirements were selected: reporting on conflicts of interest and study funding, that were included in the Recommendations much earlier. It is also of interest to determine whether supplementary material may be included online, as this is sometimes a way of including raw study data….

Sharing data from quantitative studies is much easier than from qualitative studies. Researchers performing qualitative studies frequently cite the lack of authorization of the participants, the sensitive nature of the data, and loss of confidentiality as reasons for not sharing data.6 However, qualitative studies are the exception among Spanish medical publications. By 2011, most researchers were already sharing their data, although this was challenging for more than a third of them; in the case of clinical trials, it has recently been reported that access7 to data is difficult despite authors’ commitment to share.8 Ideally, Spanish medical journals should require authors to share them in all the articles they publish, and if data sharing is impossible, to explain why.”