Slide de resumo

THE IMPACT FACTOR OF MEDICAL JOURNALS: ITS USE AND MISUSE

THE IMPACT FACTOR OF THE IMPACT FACTOR OF MEDICAL JOURNALS: MEDICAL JOURNALS: ITS USE AND MISUSEITS USE AND MISUSE

Luis Benítez-Bribiesca

Editor-in-Chief

Archives of Medical Research(México)

IMPACT FACTORIMPACT 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 FACTORIMPACT 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 FACTORIMPACT 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 1969JOURNALS WITH THE HIGHEST IMPACT FACTOR IN 1969Source: Farfield E. Citation Analysis as a Tool in Journal Evaluation. Source: Farfield E. Citation Analysis as a Tool in Journal Evaluation.

ScienceScience 1972; 178:471 1972; 178:471

ITEM ITEM ##

0001

0002

0003

0004

0005

0006

0007

0008

0009

0010

0011

0012

0013

0014

0015

CITED JOURNALCITED 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 1969 CITATION TO 1967 AND 1968 1967 AND 1968

ARTICLESARTICLES

820

184

448

804

932

572

228

192

144

7340

232

11548

2700

452

408

ARTICLES ARTICLES PUBLISHED IN PUBLISHED IN 1967 AND 19681967 AND 1968

28

8

20

39

53

33

14

20

16

833

27

1348

325

55

50

IMPACT IMPACT FACTORFACTOR

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 1999JOURNALS WITH THE HIGHEST IMPACT FACTOR IN 1999Source: Source: Journal Citation ReportsJournal Citation Reports ( (JCRJCR) on CD-ROM 1999 Science Edition Journal ) on CD-ROM 1999 Science Edition Journal

RankingsSorted by Impact FactorRankingsSorted by Impact Factor

RANKRANK

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

JOURNALJOURNAL

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 TOTAL CITESCITES

11865

16683

159955

34030

303563

134065

20043

6170

11992

265921

11061

6824

2564

25361

4360

IMPACT IMPACT FACTORFACTOR

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

21.175

ARTICLESARTICLES

29

30

346

210

1016

380

165

24

91

971

32

21

18

113

18

JOURNALS PUBLISHING REVIEW ARTICLES WITHINJOURNALS PUBLISHING REVIEW ARTICLES WITHINTHE 50 MOST CITED IN 1969THE 50 MOST CITED IN 1969

Source: Garfield E. Citation Analysis as a Tool in Journal Evaluation.

Science 1972; 178:471

ITEM #ITEM #

0001

0002

0003

0004

0005

0006

0007

0008

0009

JOURNALJOURNAL

PHARMACOL REV

BACTERIOL REV

PHYSIOL REV

SOLID STATE PHYS

Q REV

CHEM REV

ANNU REV PL PHYSIOL

ANNU REV MICROBIOL

BIOL REV

1969 CITATION 1969 CITATION TO 1967 AND TO 1967 AND

1968 ARTICLES1968 ARTICLES

448

804

572

228

452

408

296

288

176

ARTICLES ARTICLES PUBLISHED IN PUBLISHED IN 1967 AND 19681967 AND 1968

20

39

33

14

55

50

42

44

34

IMPACT IMPACT FACTORFACTOR

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 JOURNALS PUBLISHING REVIEW ARTICLES WITHIN THE 50 MOST CITED IN 19991999

Source: Source: Journal of Citation ReportsJournal of Citation Reports ( (JCRJCR) on CD-ROM 1999 Science Edition Journal Rankings Sorted ) on CD-ROM 1999 Science Edition Journal Rankings Sorted by Impact Factor.by Impact Factor.

RANKRANK

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

JOURNALJOURNAL

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 CITESTOTAL CITES

11865

16683

6170

11992

11061

6824

25361

4360

8308

14518

6416

6482

6512

3969

5893

3152

6264

IMPACT FACTORIMPACT 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

11.887

ARTICLESARTICLES

29

30

24

91

32

21

113

18

32

64

35

25

18

14

91

14

92

BIOMEDICAL JOURNALS WITH THE HIGHEST IMPACT FACTOR BIOMEDICAL JOURNALS WITH THE HIGHEST IMPACT FACTOR (1999)(1999)

Source: Source: Journal Citation ReportsJournal Citation Reports ( (JCRJCR) on CD-ROM 1999 Science Edition Journal Rankings Sorted ) on CD-ROM 1999 Science Edition Journal Rankings Sorted by Impact Factorby Impact Factor

RANKRANK

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

JOURNALJOURNAL

NAT MED

J EXP MED

J CLIN INVEST

HUM GENE THER

GENE THER

LAB INVEST

MOL MED TODAY

CANCER GENE THER

MOL MED

J MOL MED-JMM

P SOC EXP BIOL MED

ANTISENSE NUCLEI A

EXP HEMATOL

VACCINE

J HEMATOTH STEM CELL

TOTAL TOTAL CITESCITES

20043

68208

81251

6449

4249

12017

929

866

1557

1572

7227

934

4227

6341

1035

IMPACT IMPACT FACTORFACTOR

26.584

15.651

10.921

6.403

5.237

4.530

4.411

4.188

4.155

3.748

3.559

3.441

3.258

3.173

3.116

ARTICLESARTICLES

165

132

374

253

237

171

61

62

68

123

121

65

196

544

31

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

RANKRANK

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

JOURNALJOURNAL

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 TOTAL CITESCITES

134065

64762

112952

36492

2426

20067

50603

21241

4425

2465

741

1811

358

4873

2149

IMPACT IMPACT FACTORFACTOR

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

2.277

ARTICLESARTICLES

380

364

1108

221

33

266

761

168

29

49

47

77

38

176

83

THE USE OF IMPACT FACTORTHE 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 FACTORTHE 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 FACTORTHE 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 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 FACTORTHE 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 FACTORTHE 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 PROBLEMS ASSOCIATED WITH THE USE JOURNAL IMPACT FACTORSJOURNAL 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 PROBLEMS ASSOCIATED WITH THE USE JOURNAL IMPACT FACTORJOURNAL 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 LEADING LATIN AMERICAN NATIONS CITED IN THECITED IN THE SCISCI

Source: Ardila R. Scientific Publishing in Latin America. Mexico (1999)Source: Ardila R. Scientific Publishing in Latin America. Mexico (1999)

COUNTRY AVERAGE IMPACT FACTOR

BRAZIL 0.646

ARGENTINA 0.352

MEXICO 0.332

CLINICAL MEDICINE AND EMERGING CLINICAL MEDICINE AND EMERGING FIELDSFIELDS

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 CLINICAL MEDICINE AND EMERGING FIELDSFIELDS

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.