Introduction – Authors need to discern how a publication is valued before deciding where to send their manuscripts. Many properties of a medical journal can be assessed; one of them is impact factor (IF). Most scientists agree that, at least within a given field, there is some correlation between quality and IF.
In addition to helping libraries decide which journals to purchase, IFs are used by authors to decide where to submit their articles. Librarians can help authors by providing information on IFs. IFs are published with months of delay and several changes can be observed through time when IFs are analysed.
Endocrinology and metabolism are emergent research areas; journals with IF in the Journal Citation Reports (JCR) section have increased in the last years. Main goal of this study was to evaluate the time trends of journal IFs in this section.
Methods – Journals included in “Endocrinology and Metabolism” section of JCR where analysed from 1987 to 2002 (journals that had IF at least in the last three years). Time trend was evaluated by means of a linear regression model where IF was the dependent variable and year was the independent one. Model’s slope (s) and its statistical significance were considered as indicators of annual change.
Results – IFs of the 95 studied journals ranged form 0.09 to 21.64 in 2002. Five journals that showed bigger increases in IF had mean IFs > 6 in 2002 (Endocr Rev s=0.907 p<0.001, J Pediatr Endocr Met s=0.898 p=0.122, Curr Opin Lipidol s=0.699 p=0.007, Endocr Relat Cancer s=0.672 p=0.013 and Front Neuroendocrin s=0.591 p=0.004). No defined trend was found in 35 (37%) journals. Detailed results and analysis of particular cases will be presented in tabulated and graphical displays of IFs evolution.
Discussion, conclusions -
Studies have shown that use of IF as a measure of quality is widespread because it fits well with the opinion researchers have of the journals in their speciality.
This study shows that, even if some journals showed changing points in their trend, the study of the temporal evolution of IFs can be useful for authors and can help them to choose the journal before submitting a manuscript.
These data can be useful to forecast IFs evolution and this should be especially interesting because IFs are published with months of delay. Accesibilty to this information in health libraries can be very useful for librarians and researchers.
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