Scientometrics, Vol. 38, No. 2 ( Jointly published by Elsevier Science Ltd, Oxford and Akadémiai Kiadó, Budapest

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1 Scientometrics, Vol. 38, No. 2 ( Jointly published by Elsevier Science Ltd, Oxford and Akadémiai Kiadó, Budapest IMPACT FACTOR AND INTERNATIONAL COLLABORATION IN CHILEAN PHYSICS: E.E.VOGEL Departamento de Ciencias Físicas, Universidad de la Frontera, Casilla 54-D, Temuco (Chile) (Received September 18, 1996) The 598 papers on physics published between 1987 and 1994 with at least one author presenting Chilean affiliation are scrutinized. Several aspects are cross-examined along the period of eight years: number of papers, cumulative impact factor, average impact factor, international co-authorship, most visited journals and main Chilean institutions. It is found that physics is growing in Chile with international collaboration playing an important role The average impact factor is relatively high and rather constant throughout the period reflecting that the good level of Chilean physics is stable. The articles spread in 165 different journals, but most of the productivity is to be found in a few journals of high impact factor. Most of the research is done by institutions in santiago but other emerging institutions are also identified. Introduction International collaboration is essential in modern science. The role of common work of scientists over the borders is subject of permanent study [1,2]. Portions of scientific knowledge are elaborated in different parts of the world and put together in a paper or a book. For developing countries this is a certain way for closing the gap with respect to more developed nations. On the other hand, not all the publications spread scientific knowledge with the same power. The so-called impact factor (IF) tries to measure the use of the published material of each journal in subsequent publications on the field [3]. This can also be viewed as the number of expected citations [4,5]. The first studies on scientific productivity made use of the number of published papers. Nowadays, the importance of IF is even discussed within institutions when looking at their productivity [6]. In the present paper we want to examine the Chilean productivity on physics in terms of number of papers, IF and international collaboration. The period of 1987 through 1994 is chosen since there are good data bases for Chilean physics at disposal that allow a reliable study [7]. Comparison with equivalent data for developing countries is difficult at the moment. However, there are some points of contacts that are discussed when appropriate. In particular a recent article in Science can give a general background on

2 scientific productivity in the four most productive countries in Latin America: Brazil, Argentina, Mexico and Chile [8]. An independent study, covering science in the 10 most productive countries in Latin America and the Caribbean, was also published recently [9]. In these articles it is shown that the IF of physics in Chile appears to grow steadily with respect to the Latin-American background approaching slowly the world average. This observation provides one of the reasons to get deeper into the IF of the Chilean papers on physics. A fresh article on physics in Mexico also provides a possibility of comparison in some topics [10]. Another motivation for the present work is to examine the international co-authorship in Chilean physics. In general studies published so far, Chilean science appears rather isolated [2]. Even in a particular analysis on physics, Chile appears unconnected if standards intended for developed countries are used [l]. However, as we will show below, more than 40% of papers on physics originated from Chile present international collaboration and the IF associated to these papers is higher than average. Methodology The Comisión Chilena de Investigación Científica y Tecnológica (CONICYT) has gathered information about the productivity of Chilean scientists in the recent years. The sources of information were different services of bibliographic information available in the world. Such a listing of references to Chilean papers on physics is the basis of the present work and it is called DATA1. However, this data was elaborated and complemented in the way we discuss in the following lines. All departments of physics in Chile were asked for copies of the papers published after Additionally, authors that were already known from DATA1 were individually contacted asking for their productivity after In this way several papers were added to DATA1 obtaining what we call DATA2. Then a first trimming of the data was done. Time was restricted to years after 1986 to ensure homogeneity and reliability in the sense that very little (if any) of the productivity is left out. Also, only papers published in journals with impact factor (IF) assigned by the Institute for Scientific Information (ISI), were considered for the new database called DATA3. This leaves out the productivity published in local sources not covered by ISI. This can be a cause for discrepancy with other studies for Latin American countries where additional sources of bibliographical items are included [9]. Such difference was established for the case of Mexican physics, where the Mexican Physical Society counts almost twice the number of papers as reported by ISI Journals [10]. The IF values used below were taken from the.journal of Citatron Reports 1993 available at CONICYT Library [3]. Only papers on physics were kept. This was achieved by fixing two criteria. First, papers with at least one afflliation to a physics institution were considered, disregarding papers with affiliations only to interdisciplinary sciencies such as astrophysics, geophysics and others. Contributions from non-physics institutions were included only if the journal is considered belonging to any subject category related to physics as given by ISI in.journal Citation Reports 1993 [3]. Only papers originating at least partially from inside Chile were kept. In this respect there is not just one way of counting papers as thoroughly discussed by Lecrerc and Gagné [11].

3 One is fractional counting in which each paper is divided in shares among the participating countries; we will use this method for the cumulative impact factor to be considered below. Another method is the whole counting, where each paper is assigned only to one country according to the number of authors, first author or any other arbitrary way of ascribing a paper from several sources to just one origin; this method will not be considered here. Finally, it is also possible to use multiple counting in which every country present in a paper is counted once despite the number of authors it provides; we will use this method in relation to the presence of a country in each paper. The same method will be applied to count the presence of the different Chilean institutions. The presence of foreign countries, as well as local institutions, takes into consideration the main addresses only (as given in the byline). We disregard secondary affiliations which are appropriate to the author but not to the paper. So the corrected listing included only articles with at least one author with main address in Chile. We do not include here the productivity of Chilean physicists with affiliation to foreign institutions only. This elaborated data is called DATA4. A complete listing of the 598 papers contained in DATA4 is given as an Appendix of a recent book [7]. This is the database that will be used in the present work. For the purposes of the present paper, each paper was considered according to the following characteristics: - Year of publication; - Countries involved; - Chilean institutions involved; - IF of the journal. Results and discussion Productivity increases with time as shown in Fig. l where the height of the bars represents the total number of papers for each of the eight years under consideration. The filled part of each bar is proportional to the number of papers with international collaboration. Fig. 1. Number of published papers for each year between The filled part of each bar measures the number of papers with international collaboration A way to ponder the relative importance of the different journals is to look at the number of times they are cited. ISI has defined the already mentioned IF as the ratio of the number of citations of source items published during to years, over the number of articles published

4 by the journal those two years. In an approximate way, IF represents the average number of citations an article published in certain journal is expected to get each year. When each paper in DATA4 is weighted by the IF of the corresponding journal the cumulative impact factor per year is obtained. This is plotted by the height of the bars in Fig. 2, where the filled component represents the cumulative IF corresponding to the papers with international collaboration. It follows from previously commented illustrations that Chilean physicists are reaching a productivity of 100 international papers per year accumulating a total IF close to 200. The growth in the total number of papers is followed in parallel by the growth in cumulative IF This means that the average IF, <IF>, is approximately constant during the period. This is investigated in Fig. 3 where we report three related magnitudes: a) Average IF for all papers of each year under study (empty bars); b) Average IF for the papers with international collaboration (filled bars); c) Average IF for the papers without international collaboration (dashed bars). Fig. 2. Cumulative IF per year as a function of time in the period, measured by the height of the bars. The filled part corresponds to the IF accumulated by articles with foreign collaboration International collaboration plays an important role for Chilean physics. From the 598 papers in DATA4, 262 were articles coauthored internationally representing a 43.8%. The average value in the world is 26.8%, while this percentage for other countries is as follows: USA 19.2%, Great Britain 33.0%, France 37.1%, Germany 39.0% [11] The international collaboration has been done with 27 different countries. In Table 1 we report the number of presences for each of the 9 countries that contribute the most. (Notice than in some papers more than one foreign country might participate.) This table lists the countries that hold permanent ties to Chilean science as can also be found by looking at the

5 Projects of International Collaboration recognized by CONICYT, usually listed in different issues of Panorama Científico [12]. Fig. 3. Average IF per year during the eight years of the period under study. Empty bars represent the general average. Filled bars represent the average for articles with foreign collaboration only. Dashed bars represent the average for papers with Chilean authors only Table 1 International collaboration in Chilean productivity on physics. Countries are listed in column 1. The number of papers between per country is given in the second column (multiple counting). Third column renders the cumulative IF, after splitting the individual IF of each paper among Chilean institutions and foreign counties collaborating in it (fractional counting). Finally we list the average IF considering all the publications where each country is present (multiple counting) Country # Papers Cumulative IF Average IF Argentina Belgium Brazil Germany Spain France Great Britain México U.S.A The impact of the papers on physics originating from Chile is the highest among countries in Latin America [8,9]. Let us examine results available in the literature for the year The relative IF for Chilean physics with respect to the world average (defined at 1.0) is close to 0.75, while Argentina, Brazil and Mexico are close or slightly under 0.6 [8] If the cumulative citation impact relative to the world (defined at 1.0) is considered,

6 Chilean physics ranks first with 0.77, followed by Argentina (0 62), Venezuela (0.60), Brazil (0.59) and Mexico (0.53) [9]. In the present paper we investigate tendencies on the absolute IF both in terms of cumulative IF by means of fractional counting, as well as <IF> by means of multiple counting. It turns out that <IF> is 1.85 for the eight-year period. This value raises to 2.05 when only articles coauthored internationally by Chilean physicists are considered. Fluctuations are relatively small as seen from Fig. 3. _ Fig. 4. Spectral distribution of IF corresponding to the 598 papers of the period arranged in channels at intervais of 0.5. Last channel includes all papers published in journals with IF equal or larger that 3 5. The filled part of the bar represents articles with international co-authorship The composition of such a stable value for <IF> is investigated by performing a spectral analysis of the journals in the way presented by Fig. 4. Eight channels are established: The lower seven channels are defined in ranges of 0.5 in relation with the IF of the corresponding journal; the eighth channel gathers all the papers published in journals with IF larger than 3.5. Each channel of Fig. 4 also discriminates between the total productivity (height of the bars) and the contribution of the interrtational collaboration (height of the filled part of the bar). Three comments flow from this last figure. First, the rather flat distribution for IF<2.5, without indication for a large number of publications in journals of low IF (first channel for instance). Second, a strong second distribution for IF23.0, indicating that a significant portion of Chilean physics finds its way to the most prestigious joumals in the world. Third, the international collaboration is distributed through all channels but it is more important in the second distribution of higher IF just mentioned in previous point.

7 When the spectral distribution of Fig. 4 is studied for each of the eight years in the period (not shown) no significant variations are found. This means that Chilean physics in spite of its modest volume shows a permanent tendency toward high impact factors. An interesting fact is that the 598 articles are spread throughout 165 different journals. As a consequence of this scattering, 81 titles were visited just once during the eight years. In that sense the stability of the previously reported results is remarkable. On the other hand, we can look at the most frequently used journals, which can also give an idea of some well established fields. In Table 2 we list all the journals that were visited at least 16 times in the 8 years, that is to say, twice a year in the average. They are listed in decreasing order with respect to the number of published papers as given in the second column. Next column gives the percentage of articles with foreign co-authorship. The fourth column adds up the IF accumulated by each journal. Table 2 Journals visited at least twice per year (in the average) during the period The abbreviation is the usual one as given in the lists of ISI. From left to right, columns measure the number of papers, percentage of papers with international co- authorship (multiple counting) and cumulative IF, respectively (fractional counting) Journal # Papers % Intemational Cumulative IF PHYS REV B PHYS LETT B PHYS REV A SOL STATE COMM PHYS REV D PHYS STA SOLI B J PHYS A MATH G PHYS REV LETT J MATH PHYS Physical Review B is the most popular journal among Chilean authors, which tells that condensed matter physics is a well established field in the country. This is reinforced by the accompanying journals Solid State Communications and Physica Status Solidi B. The subjects of mathematical physics, fields and particles are also well represented in Table 2. On the other hand, Physical Review B, Physical Review Letters and Physics Letters B account for one third of the total cumulative IF (1099.4). These three journals and Physical Review D show the highest presence of international collaboration. The participation of Chilean institutions has been also considered. It turns out that the two Departments of Physics of Universidad de Chile and the Faculty of Physics of Pontificia Universidad Católica are the three leading institutions. They produce about 3/4 of the physics published internationally, covering most of the areas of modern physics. In a second row we can find three other institutions: Centro de Estudios Científicos de Santiago, Universidad Técnica Federico Santa Maria (Valparaíso) and Universidad de Santiago de Chile. The sum of their productivity is comparable to the average of the leading three institutions. In a third level there are other institutions generally being productive on

8 one or two fields: Universidad Católica de Valparaíso, Universidad de Concepción, Universidad de Tarapacá (Arica), Universidad de la Frontera (Temuco), Comisión Chilena de Energía Nuclear (Santiago), Universidad Austral de Chile (Valdivia). The rest of the productivity is scattered among other institutions throughout Chile. A detailed account of the productivity of the previously listed institutions has been reported elsewhere [7,l3] The stratification proposed above follows very closely a study of productivity of Chilean universities done a few years ago [l4]. That study left out the two research centers listed in previous paragraph, considered all fields of activity and covered years 1987, 1988 and In spite of these differences one can find a close correspondence with the present findings for physics. Conclusions Chilean physics presents a steady growth measured in terms of number of published papers and in terms of cumulative impact factor of the journals where the paper appeared. At present, more than 100 papers are published yearly accumulating an IF of about 200. About 43.8 % of the papers are done with foreign co-authorship. Almost half the total IF corresponds to publications presenting international collaboration. Countries that collaborate with Chilean physics in order of decreasing number of collaborations are: USA, Argentina, Belgium, France, Brazil, Germany and other 21 nations. The IF averaged over one year is 1.85 showing minor fluctuations with time. The average IF is higher for papers including foreign coauthors: The spectral distribution of the IF associated to the different journal visited by Chilean physics present a rather flat behavior betvveen 0.0 and 2 5. There is a clear second distribution, with high international co-authorship, for IF larger than 3.0. The most frequently used journals with high IF are the series of Physical Review (the C volumes would be next in Table 2 with 15 articles) and Physics Letters B. Precisely in these journals is where the international co-authorship reaches its apex. The institutions that provide the 598 articles in DATA4 can be grouped in four levels. First, those institutions producing most of the papers, most of the IF and covering several fields of modern physics (Universidad de Chile and Pontificia Universidad Católica). Second, three institutions permanently contributing in two or more fields. Third, about six institutions producing constantly mainly on one or two subjects. Fourth, scattered productivity without a definite pattern in speciality or presence in time. This work has been partially funded by Fundación Andes (Chile) under Contract No. C The author wishes to thank Prof. Manuel Krauskopf and Miss Ana María Prat for discussions and comments. The library at CONICYT was extensively used. References 1.T. BRAUN, Y. GÓMEZ, A. MÉNDEZ, A. SCHUBERT, International co-authorship patterns in Physics and its subfields, , Scientometrics,24(1992)

9 2. J. F. MIQUEL,T. OJASOO, Y. OKUBO, A. PAUL, J. C. DORÉ, World science in 18 disciplinary areas: Comparative evaluation of the publication patterns of 48 countries over the period , Scientometrics, 24 (1995) Journal of Citation Reports, Institute for Scientific Inforrnation (Philadelphia, USA, 1993) 4. T. BRAUN, W. GLANZEL, H. MACZELKA, A. SCHUBERT, World science in the eighties. National performances in publication output and citation impact, versus Part 1, Scientometrics, 29 (1994) T. BRAUN, W. GLANZEL, H. MACZELKA, A. SCHUBERT, World science in the eighties. National performances in publication output and citation impact, versus Part 11, Scientometrics, 31 (1994) H. DELGADo, J. M. RUSSELL, Impact of studies published in the international literature by scientists at the National University of Mexico, Scientometrics, 23 (1992) E. VOGEL, La Física en Chile Hacia Fines del Siglo XX, De. Universidad de La Frontera, Temuco, Science in Latin America, Science, 267 (1995) M. KRAUSKOPF, M. I. VERA, V. KRAUSKOPF, A. WELLJAMS-DOROF, A citationist perspective on science in Latin America and the Caribbean, Scientometrics, 34 (1995) M. A. PEREZ-ANGÓN, G. TORRES-VEGA, Una visión de la fisica mexicana, Avancey Perspectiva, 15 (1996) M. LECLERC, J. GAGNÉ. International scientific cooperation: The continentalization of science, Scientometrics, 31 (1994) Panorama Cientifico, Periodic Bulletin of Comisión Nacional de Investigación Científica y Tecnológica, containing information about Chilean science 13. E. E. VOGEL, Impact factor in Chilean publications of physics proceedings of the X. Southern Workshop on Solid State Physics, Dichato (Chile) April 1996, (in press). 14. M. KRAUSKOPF, Scientometric indicators as a means to assess the performance of state supported universities in developing countries: The Chilean case, Scientometrics, 23 (1992)