Why double-blind review is preferable for scholarly journals.

There are three widely practised models of peer review for scholarly papers: (i) single-blind, (ii) double-blind, and (iii) open or public. When manuscripts are processed by journal editors through the single-blind peer review, several factors may confound the objectivity of the processing and decision-taking. The most important one is authors' nationality or country origin. Reviewers may be biased towards submissions from certain countries owing to political and/or ethnic issues. Such non-financial conflicts of interest, often undisclosed, are threats to the whole system of peer review (1). An example of conflicts related to nationality surfaced at the time of "scientific embargo" imposed by the US and the EU on Iranian authors, who often consider most impacting journals as homes for their best research papers (2, 3). The second factor is gender. Reviewers may inconsistently judge similar manuscripts written by male and female authors, and particularly by corresponding authors. Some individuals may sympathise authors of opposite gender and overlook shortcomings of their papers. Gender conflicts may also lead to unjustifiably harsh critics and unfair reviewer recommendations. The third factor is authors' age and previous publications record. Reviewers may choose to look at authors' profile on bibliographic databases and online platforms. And subjective erroneous recommendations can be made, considering authors' international reputation, publication records, and impact indicators. Young researchers' work is likely to be criticized and rejected despite its strengths and value for the scientific community (4). This is why some journals offer an option to recommend potential reviewers, who are likely to objectively evaluate authors' submissions. Double-blinding also ensures that authors' reputation does not influence reviewers' judgments (5). Finally, authors' affiliation is a critical factor affecting reviewer's recommendations. For example, scholarly works from chemical engineering and mechanical engineering subject categories often reach similar priorities. However, reviewers from one subject category may unfairly diminish value of works from another category, which, again, necessitates masking of authors' and reviewers' identity, including their affiliations. One can conclude that the double-blind review model is more expedient and fair.