The Relationship between Citation Indicators and Category of Journals by the Bradford Method , Case Study: Journal of Infertility

Periodical publications are one of the resources through which users reach the scientific publications and scientific productions from different groups of researchers. Among documents and publication resources, the periodical publications are considered the most important resources for scientific information due to their speed of publishing and the effective role they play in the transmission of information. The level of production and quality of publications are among the indicators of the scientific and cultural growth in any society (Fat'habadi, Kamari and Sharifi, 2015). Publications play a role in continuous education and improvement in research and distribution of scientific activities (Sieger, 2003). The European Union Commission has confirmed this and believes that scientific publications have a dual role in the validation and dissemination and this is important in archiving knowledge and to guarantee permanent access to it (European Commission, 2006). To value scientific publications equals their continuous assessment, taking care production of knowledge and science; and dissemination and sharing of that knowledge. Nowadays, scientometrics has been defined as a method to measure science, which defines the achievements of an intellectual realm and even predicts possible lines for further progress through examination and discovery of system and structure of science field by using quantitative means. One could assess the distribution of frequency as well as the evaluation of scientific entities such as publications through the application of the techniques and laws available in Scientometrics. The purpose of this study was to investigate the relationship between citation indices and classification of publications in the field of infertility through Bradford method.

This descriptive correlation study was done by Scientometrics survey. The sources of data collection were all ranking reports of infertility journals from Thomson Reuters (JCR) and Scopus (SCImago) in the period 2014-2012.  Infertility journals in the PubMed database form the research community. In order to collect data in the first stage, the list of indexed journals in the field of infertility was extracted from the PubMed database. The indexing of journals in PubMed database was reviewed through the website of the National Library of Medicine of America. In this study, Bradford Law was applied to include a number of proper journals. As a result, 92 journals were selected according to Bradford Law: the first category (4 journals), the second category (16 journals), and the third category (72 journals). Then, the values of STR, H- index, from the SCImago and impact factor from the JCR database were extracted. The extracted values were taken as the basis for analyzing and studying the relationship between the indices. Excel and SPSS software were used to analyze the data while Pearson correlation test and linear regression were used due to the quantitative nature of research variables.

The results of the fitting distribution of specialized journals in the field of infertility according to Bradford Law showed that the number of publications of each category has increased with a constant coefficient compared with its previous category. This constant coefficient indicates that the distribution of journals in these three categories is consistent with the distribution of Bradford. According to the research findings, the impact factor, SJR with H- index of infertility journals is positively correlated with Bradford's frequent distribution of these journals.

In general, according to the results of this study, the selection of publications with each of the evaluations of the SCImago and JCR and the law Bradford in the field of infertility is possible due to the correlation between them, although there was a very little difference between this correlation from the publications of the first category to all journals. Given the disadvantages of the impact factor, as well as the differing rankings of the journals and the number of indexed publications in the bases, along with other studies; these indicators can be a good benchmark for top journals. Along with the present study, Myers and Young (2017) showed that neither of the indicators of evaluation of the journals are superior to each other, but indicators such as the H index are more effective in evaluation of management and business journals. In general, the present study, along with other studies, confirmed the features of empirical rules (in the present study, Bradford) such as categorization and generalization (Tavakolizadeh and Soheili, 2015).   According to the results, researchers and authors of infertility field can use the impact factor, SJR, Bradford law and H- Index to select appropriate journals in their specialized field. It is also proposed to do similar research on the relationship between indices in other journals and the comparative evaluation of other citation metrics of journals at different fields.