Presentation on theme: "Slide de resumo THE IMPACT FACTOR OF MEDICAL JOURNALS: ITS USE AND MISUSE."— Presentation transcript:
Slide de resumo THE IMPACT FACTOR OF MEDICAL JOURNALS: ITS USE AND MISUSE
Luis Benítez-Bribiesca Editor-in-Chief Archives of Medical Research (México)
IMPACT FACTOR Counting references to rank the use of scientific journals was reported as early as 1927 by Gross and Gross. The term “impact factor” was not used until the publication of the 1961 in Science Citation Index (SCI) in 1963. This led to a byproduct, Journal Citation Reports (JCR), and a burgeoning literature using bibliometric measures. Source: Garfield E. How can impact factors be improved? BMJ 1966; 313:413-5.
IMPACT FACTOR The most used data in the JCR are impact factors-ratios obtained from dividing citations received in 1 year (numerator) by papers published during the two previous years (denominator). JCR’s impact calculations are based on original research and review articles, as well as on notes. Letters of the type published in the BMJ and the Lancet are not included in the publication count, but all references are counted in the numerator.
IMPACT FACTOR The scope of bibliometric studies is the treatment and quantitative analysis of scientific publications. They belong to the so-called “social studies of science” and science policy constitutes one of its main applied fields.
JOURNALS WITH THE HIGHEST IMPACT FACTOR IN 1969 Source: Farfield E. Citation Analysis as a Tool in Journal Evaluation. Science 1972; 178:471 ITEM # 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 0014 0015 CITED JOURNAL ACCOUNTS CHEM RES ADV PROTEIN CHEM PHARMACOL REV BACTERIOL REV ANNU REV BIOCHEM PHYSIOL REV SOLID STATE PHYS ADV ENZYMOL INT REV CYTOL J MOL BIOL REC PROG HORMONE RES P NAT ACAD SCI USA J EXP MED Q REV CHEM REV 1969 CITATION TO 1967 AND 1968 ARTICLES 820 184 448 804 932 572 228 192 144 7340 232 11548 2700 452 408 ARTICLES PUBLISHED IN 1967 AND 1968 28 8 20 39 53 33 14 20 16 833 27 1348 325 55 50 IMPACT FACTOR 29.285 23.000 23.400 20.615 17,584. 17.333 16.285 9.600 9.000 8.811 8.592 8.566 8.307 8.218 8.160
JOURNALS WITH THE HIGHEST IMPACT FACTOR IN 1999 Source: Journal Citation Reports (JCR) on CD-ROM 1999 Science Edition Journal RankingsSorted by Impact Factor RANK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15JOURNAL ANNU REV IMMUNOL ANNU REV BIOCHEM CELL NAT GENET NATURE NEW ENGL J MED NAT MED ANNU REV CELL DEV BI CURR OPIN CELL BIOL SCIENCE PHYSIOL REV ANNU REV NEUROSCI CA-CANCER J CLIN CHEM REV ANNU REV PHARMACOL TOTAL CITES 11865 16683 159955 34030 303563 134065 20043 6170 11992 265921 11061 6824 2564 25361 4360 IMPACT FACTOR 47.564 37.111 36.242 30.693 29.491 28.857 26.584 26.263 25.631 24.595 23.953 22.605 22.327 21.244 21.175ARTICLES 29 30 346 210 1016 380 165 24 91 971 32 21 18 113 18
JOURNALS PUBLISHING REVIEW ARTICLES WITHIN THE 50 MOST CITED IN 1969 JOURNALS PUBLISHING REVIEW ARTICLES WITHIN THE 50 MOST CITED IN 1969 Source: Garfield E. Citation Analysis as a Tool in Journal Evaluation. Science 1972; 178:471 ITEM # 0001 0002 0003 0004 0005 0006 0007 0008 0009JOURNAL PHARMACOL REV BACTERIOL REV PHYSIOL REV SOLID STATE PHYS Q REV CHEM REV ANNU REV PL PHYSIOL ANNU REV MICROBIOL BIOL REV 1969 CITATION TO 1967 AND 1968 ARTICLES 448 804 572 228 452 408 296 288 176 ARTICLES PUBLISHED IN 1967 AND 1968 20 39 33 14 55 50 42 44 34 IMPACT FACTOR 22.400 20.615 17.333 16.285 8.218 8.160 7.047 6.545 5.176
JOURNALS PUBLISHING REVIEW ARTICLES WITHIN THE 50 MOST CITED IN 1999 Source: Journal of Citation Reports (JCR) on CD-ROM 1999 Science Edition Journal Rankings Sorted by Impact Factor. RANK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17JOURNAL ANNU REV IMMUNOL ANNU REV BIOCHEM ANNU REV CELL DEV BI CURR OPIN CELL BIOL PHYSIOL REV ANNU REV NEUROSCI CHEM REV ANNU REV PHARMACOL ENDOCR REV TRENDS NEUROSCI ANNU REV PHYSIOL ANNU REV PLANT PHYS PHARMACOL REV ANNU REV ASTRON ASTR CURR OPIN GENET DEV ANNU REV BIOPH BIOM CURR OPIN IMMUNOL TOTAL CITES 11865 16683 6170 11992 11061 6824 25361 4360 8308 14518 6416 6482 6512 3969 5893 3152 6264 IMPACT FACTOR 47.564 37.111 26.263 25.631 23.953 22.605 21.244 21.175 20.250 19.925 19.797 17.000 15.421 15.067 12.665 12.026 11.887ARTICLES 29 30 24 91 32 21 113 18 32 64 35 25 18 14 91 14 92
MEDICAL JOURNALS WITH THE HIGHEST IMPACT FACTOR (1999) Source: Journal Citation Reports (JCR) on CD-ROM 1999 Science Edition Journal Rankings Sorted by Impact Factor RANK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15JOURNAL NEW ENG J MED JAMA- J AM MED ASSOC LANCET ANN INTERN MED ANNU REV MED ARCH INTERN MED BRIT MED J AM J MED MEDICINE BRIT MED BULL J INVEST MED ANN MED AMYLOID CAN MED ASSOC J MED CLIN N AM TOTAL CITES 134065 64762 112952 36492 2426 20067 50603 21241 4425 2465 741 1811 358 4873 2149 IMPACT FACTOR 28.857 11.435 10.197 10.097 7.219 6.705 5.143 4.977 4.723 3.381 2.922 2.566 2.371 2.356 2.277ARTICLES 380 364 1108 221 33 266 761 168 29 49 47 77 38 176 83
THE USE OF IMPACT FACTOR The impact factor is being used with increasing frequency to evaluate the quality of a journal and the relevance of individual scientific output despite a number of articles and claims that challenge the use of this index as a sound criterion for judging the quality of both research and journals. It is frequently overlooked that Garfield himself, the inventor of the IF, emphasized that its potential value would be primarily in the management of library journal collections to determine their optimum makeup, providing solid basis for cost- benefit analysis of subscription budgets.
THE USE OF IMPACT FACTOR The impact of the IF has been so great that its use has been injudiciously extended to judge the quality of a journal and what is more distressing, the quality of scientific output. Furthermore if the IF is taken as an indication for orienting editorial policies, then scientists and journals in peripheral fields would find increasing difficulties in publishing important contributions out of the mainstreams of current scientific research. In other words, this possesses the danger to halt scientific creativity and freedom.
THE MISUSE OF IMPACT FACTOR Traditionally, committees formed by senior scientists scrutinize the scientific production of the candidate and mainly judge the quantity and quality of their publications. Quantity is easily evaluated, involving counting the number of articles, whereas quality is a notoriously difficult aspect to appraise, in that subjectivity and bias frequently overshadow the process.
THE MISUSE OF IMPACT FACTOR Most evaluation committees in developing nations currently base promotions, resource allocations, and awards solely on citation indices and IF, particularly in the medical field. What is more surprising is that most scientists and peer reviewers seem to be convinced that this is the best method for considering scientific quality.
THE MISUSE OF IMPACT FACTOR Hecht et al warn that IF should not be misused to evaluate journals or to validate scientific relevance, especially in decisions regarding employment, funding, and academic promotions. They emphasize that IF has clearly become a key marketing tool in biomedical publishing, and fear that editorial policies, once determined by scientific editors, may increasingly be dictated by executives and accountants.
THE MISUSE OF IMPACT FACTOR Garfield points out that successful editors and publishers know that in order to improve the editorial quality of journals, there is no substitute for good judgment, quality, and relevance. Impact and other citation measures merely report the facts.
PROBLEMS ASSOCIATED WITH THE USE JOURNAL IMPACT FACTORS Journal impact factors are not statistically representative of individual journal articles. Journal impact factors correlate poorly with actual citations of individual articles. Review articles are heavily cited and inflate the impact factor of journals. Long articles collect many citations and yield high journal impact factors. Short publications lag allows many short-tem journal self-citations and produces a high journal impact factor. Citations in the national language of the journal are preferred by the journal’s authors. Database has an English language bias. The database is dominated by U.S. Publications. Impact factor depends on the dynamics (expansion or contraction) of the research field. Small research fields tend to lack journals with high impact. The citation of articles determines journal impact but not viceversa. Citation is biased when publications come from scientifically less developed countries. A good example is what occurs in Latin America.
PROBLEMS ASSOCIATED WITH THE USE JOURNAL IMPACT FACTOR Articles that came directly from Latin America in 1995 represented only 1.8% of the total. Even so, this represents an increase from 1981, in which year the figure was 1.3%. Another important finding was that 85% of the scientific articles originating in Latin America came from only four countries: Brazil, Argentina, Mexico and Chile. These articles were cited between 40% and 60% less than the world average for papers in the same field.
LEADING LATIN AMERICAN NATIONS CITED IN THE SCI Source: Ardila R. Scientific Publishing in Latin America. Mexico (1999) COUNTRYAVERAGE IMPACT FACTOR BRAZIL0.646 ARGENTINA0.352 MEXICO0.332
CLINICAL MEDICINE AND EMERGING FIELDS There is a great difference in the numbers of citations between basic biomedical research and purely clinical publications. Biomedical research, particularly if releated to molecular genetics, tends to be highly cited, while clinical publications are not. Clinical medicine publications draw heavily on basic science references, but not viceversa.
CLINICAL MEDICINE AND EMERGING FIELDS The goals of the scientist can be diverted from the original purpose of scientific endeavor towards achieving a higher citation rate, especially in the biomedical sciences. To obtain the benefits of funding and academic promotion, most medical scientists prefer to work in molecular genetics rather than to participate in patient-oriented research. This is contributing to the progressive decline of physician-scientists.
AGONY OF IF. THE INTERNET The radical change brought about by the Web for publishing and searching scientific literature is changing the classical scheme of printed library collections and private journal subscriptions. It is, therefore, foreseeable that the IF will lose its significance to the extent that electronic publishing and free access to databases substitute for printed journals.