1. Analysis of Evolution of Impact Factors of Endocrinology and Metabolism Journals (1987-2002) Concepción Muñoz Tinoco 1, Elena Guardiola 2, Gonzalo López-Abente 3 1 Library. Hospital Ramon y Cajal. Ctra. Colmenar km 9. 28034 Madrid –Spain. 2 Medical Information and Documentation Department. Q. F. Bayer. Pau Claris 196. 08037 Barcelona – Spain. 3 Environmental Epidemiology and Cancer Department. National Center for Epidemiology-ISCIII. Sinesio Delgado, 6. 28029 Madrid - Spain Introduction Authors need to discern how a publication is valued before deciding where to send their manuscripts. Most scientists agree that, at least within a given field, there is some correlation between quality and Impact Factor (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. Objective To evaluate the time trends of journal IFs in Endocrinology and Metabolism section of Journal Citation Reports (JCR). 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 (Figure 1) ranged form 0.09 to 21.64 in 2002. Four journals that showed bigger increases in IF had mean IFs > 6 in 2002 (Tables 1 and 2) (Endocr Rev s=0.907 p<0.001, 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. Discussion and conclusions The 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. Accessibility to this information in health libraries can be very useful for librarians and researchers. Table 2. Top 20 journals sorted by 2002 Impact Factor (1987-2002) title s 2002 IF mean p-value ENDOCR.REV 0.907 21.643 17.555 0.000 FRONT.NEUROENDOCRIN 0.591 11.136 7.921 0.004 DIABETES 0.282 8.256 6.306 0.000 TRENDS.ENDOCRIN.MET 0.339 7.969 3.691 0.007 MOL.ENDOCRINOL 0.080 6.623 6.759 0.117 CURR.OPIN.LIPIDOL 0.699 6.575 5.424 0.007 RECENT.PROG.HORM.RES 0.022 6.455 5.260 0.865 J.BONE.MINER.RES 0.120 6.329 5.901 0.002 ENDOCR.RELAT.CANCER 0.672 6.087 1.852 0.013 FREE.RADIOL.BIO.MED 0.350 5.533 4.448 0.016 DIABETES.CARE 0.206 5.477 3.589 0.000 J.CEREBR.BLOOD.F.MET 0.089 5.297 5.449 0.066 J.CLIN.ENDOCR.METAB 0.122 5.199 4.524 0.000 DIABETOLOGIA 0.142 5.136 4.827 0.000 ENDOCRINOLOGY 0.064 5.095 4.585 0.000 J.MOL.ENDOCRINOL 0.086 4.359 2.537 0.090 J.PINEAL.RES 0.228 3.913 2.178 0.000 BONE 0.163 3.755 2.908 0.002 VITAM.HORM 0.150 3.733 4.388 0.224 OSTEOPOROSIS.INT 0.066 3.724 3.142 0.532 Table 1. Top 20 journals sorted by annual change (1987-2002) title s 2002 IF mean p-value ENDOCR.REV 0.907 21.643 17.555 0.000 CURR.OPIN.LIPIDOL 0.699 6.575 5.424 0.007 ENDOCR.RELAT.CANCER 0.672 6.087 1.852 0.013 FRONT.NEUROENDOCRIN 0.591 11.136 7.921 0.004 BEST.PROCT.RES.CL.EN 0.537 1.231 0.689 0.011 DIABETES.OBES.METAB 0.389 1.077 0.704 0.045 FREE.RADIOL.BIO.MED 0.350 5.533 4.448 0.016 GROWTH.HORM.IGF.RES 0.346 1.592 1.057 0.011 TRENDS.ENDOCRIN.MET 0.339 7.969 3.691 0.007 OBES.RES 0.312 3.025 3.077 0.231 DIABETES 0.282 8.256 6.306 0.000 J.PINEAL.RES 0.228 3.913 2.178 0.000 AM.J.PHYSIOL.ENDOCM 0.206 3.620 3.277 0.010 DIABETES.CARE 0.206 5.477 3.589 0.000 J.MAMMARY.GLAND.BIOL 0.189 2.871 2.967 0.767 BONE 0.163 3.755 2.908 0.002 EUR.J.ENDOCRINOL 0.159 2.560 2.066 0.008 VITAM.HORM 0.150 3.733 4.388 0.224 PROSTATE 0.147 3.151 2.423 0.000 DIABETOLOGIA 0.142 5.136 4.827 0.000 Figure 1. Time trend of Impact Factor for the 95 journals studied (alphabetic order) 9 th European Conference of Medical and Health Library. Santander, Spain 20- 25, September, 2004