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Science with impact

List of researchers with highly cited works includes more Brazilians in 2020

Patricia Brandstatter

There has been an increase in the number of Brazilian researchers who are among the most cited in the world. There were 19 in 2020, four more than the previous year, standing out in areas such as epidemiology and public health. The data come from a survey carried out in November by the Institute for Scientific Information (ISI), a service founded on bibliometrics by Clarivate Analytics. Every year the company lists the scientists responsible for 1% of the most cited articles in 21 areas of knowledge. The 2020 report is based on works published in indexed periodicals on Web of Science (WoS) between January 2009 and December 2019, and the citations they received during the period. In total, there are 6,389 researchers on the list.

Brazil is one of 15 countries that produces the most scientific articles and was ranked 26th among the nations with the most cited scientists (see table). This reinforces the growth trend that gained strength in 2018 when Clarivate adopted a new methodology for tracking the impact of researchers. Until that time, the Brazilian contingent of the most cited researchers was limited to an average of four names—not always being the same. In 2018, this number rose to 13 and, in 2019, to 15. Brazil’s performance is low compared with other countries, such as the United States and China, but it stands out in Latin America. Brazil was ahead of Mexico, which had four researchers on the list in 2020, and Argentina, with only one. Since Clarivate undertook this survey in 2014, Brazil’s neighbor has not yet surpassed three researchers on the list.

The turning point for Brazil’s representation on Clarivate’s list coincides with the introduction of the category “cross-field citation,” which highlights researchers whose works have been cited in many studies of different areas of knowledge—in the remaining categories, the calculation is made only within the respective discipline. David Pendlebury, citation analyst with ISI, explains that the idea is to recognize influential scientists in various fields of knowledge, but who don’t have sufficiently cited articles in any of the assessed areas to appear on the final list. “Breaking down artificial walls in conventional disciplines means maintaining the relevance of the list, even more so in a context in which science is increasingly more global and interdisciplinary,” said Pendlebury to Pesquisa FAPESP.

Of the 6,389 most cited researchers in 2020, 2,493 stood out with regards to cross-field citations; four were Brazilian. One of the names is that of biologist Mercedes Maria da Cunha Bustamante, from the Institute of Biological Sciences at the University of Brasília (UnB). Her research projects look at how Brazilian biomes respond to global environmental changes, that is, modifications in periods of rain and drought triggered by climatic changes, impacts of converting native vegetation into areas of agricultural production, among others. “To allow us to identify the vectors of these changes, analyze their action mechanisms, and have a broad and integrated vision of their impacts, we need to introduce multidisciplinary approaches. We are collaborating with scientists in other areas on an increasing basis such that it is natural for our production to impact various fields of knowledge,” explains the researcher.

The Clarivate list suggests that universities of any size could have researchers among the most cited, as long as they produce quality research projects. This is the case for the Post-graduate Program in Epidemiology of the Federal University of Pelotas (UFPel), “one of the best in the world,” according to epidemiologist Pedro Hallal, chancellor of UPFel and one of the most cited Brazilians in 2020. He shares that the program began to get organized in the 1980s, beginning with the work of two other researchers who have been on the most cited list for some time. One of them is pediatrician Fernando Barros, from the Faculty of Medicine of the Catholic University of Pelotas (UCPel) in Rio Grande do Sul. For four decades he has studied the role of breastfeeding on the prevention of mortality in newborns, as well as working on the development of growth curves considered ideal during pregnancy and soon after giving birth (see Pesquisa FAPESP issue no. 225). “We study body profile and the state of newborn health where the gestation period was under the best possible conditions, compared with that of children from poor families,” clarifies Barros. “These works have implications in different areas, from sociology to economics, from medicine to political science, which helps to explain the fact that they appear among Clarivate’s cross-field citations.”

Clarivate Analytics list places epidemiology and public health in Brazil among the areas of greatest international impact

Alongside physician Cesar Victora from the Faculty of Medicine at UFPel, Barros created one of Brazil’s first birth cohorts, the name given to the studies that follow long periods of health for people born in a certain year and location. Initiated in 1982, this monitoring has generated developments leading to worldwide recognition for the couple’s work, making them benchmarks in this field. Since 2018, Victora has also been recognized as one of the most cited. “The publication of projects produced by this cohort have shown the importance of maternal breastfeeding on the reduction of infant mortality and have enabled us to create growth curves that are used today to evaluate the development of fetuses and babies in more than 140 countries,” says Victora. “These projects have international reach and direct implications for pediatrics. For this reason, they receive many citations.”

Of the 19 most cited Brazilians in 2020, only 5 (26.3%) are women. “We recognize that the list, despite its geographic diversity, is still predominantly masculine. However, based on names commonly associated with women, we note that the number of most cited researchers has grown since 2014,” points out Pendlebury. Clarivate’s list also shows how high-impact scientific production is still mostly concentrated in few states across Brazil. With the exception of Bustamante from UnB, and of food engineer Henriette de Azeredo, from Embrapa Agroindústria Tropical in Fortaleza, all of the most cited Brazilians are linked to institutions in the South and Southeast. The imbalance in the production of these studies is visible even among institutions in these regions. Of the 17 most cited Brazilian names linked to universities and research institutes in the South and Southeast, more than half are in Sao Paulo and Rio Grande do Sul (see the map).

Seven (41.1%) are from the University of São Paulo (USP), of which four are members of the group of epidemiologist Carlos Augusto Monteiro from the Faculty of Public Health (FSP) of USP. Epidemiologist Renata Bertazzi Levy, researcher at the Faculty of Medicine of USP (FM-USP), Monteiro’s partner and one of the most cited Brazilians on Clarivate’s list, explains that the team’s performance is associated with a group of published works in the last decade that are based on a food classification they proposed 10 years ago. Called Nova, it groups foods in four categories according to the degree of processing: natural or minimally processed; processed culinary ingredients; processed; and ultra-processed (see Pesquisa FAPESP issue no. 265). “We published various studies linking the consumption of ultra-processed quality foods in a diet with the development of illness,” she explains. “Some involve partnerships with other countries, which has allowed us to verify that, independent of the food standards of each region, this food group was always associated with deterioration of nutritional indicators.” The findings, according to Levy, gave each classification an international dimension. “Various groups around the world began to use it. Today there are more than 500 published articles based on it.”

The studies by Monteiro’s team, added to those of Pelotas’s researchers, place epidemiology and public health in Brazil among those of greatest international impact. According to Victora, this is due to the relationship between these areas and issues connected to socioeconomic inequality in Brazil. “Different from how epidemiology is practiced in the United States, in Brazil it has been broader historically, combining economic and social aspects around different health issues to identify their causes. This approach tends to enrich the work in these areas, in addition to increasing their intersection points with other fields of knowledge, attracting the attention of international groups,” he clarifies.

Two other names stand out on Clarivate’s list. One of them is physicist Paulo Artaxo from the Physics Institute (IF) of USP, renowned for his research on environmental problems caused by aerosols—fine particles in suspension in the atmosphere—in cities such as Sao Paulo and the Amazon region. In 2014, Artaxo appeared for the first time among the 1% of scientific elite whose articles are among the most cited. His research projects have become an international benchmark on the role of these particles in the formation of rain and the control of solar radiation levels over the large tropical forest. Another name that recurs on the list is cardiologist Álvaro Avezum, director of the International Center of Research at the Oswaldo Cruz German Hospital in Sao Paulo. Since 2014, he has appeared repeatedly among the most cited in clinical medicine. In the last two years, however, he has stood out among those with the highest number of cross-field citations, emphasizing an interdisciplinary trend in the field of health.

Avezum clarifies that the high impact of his work can be attributed to, among other things, the fact that he is a member of large international networks of multicentric research projects involving illnesses of interest. “For at least three decades, our group has been developing projects involving a collaborative network of 250 hospitals and medical clinics throughout the country. We have also represented Brazil in large international studies, such as Pure (Prospective Urban and Rural Epidemiological Study), which for 15 years has followed 300,000 individuals to understand the causes of aging,” he points out. “We always try to address clinically relevant issues. Thus, we focus on strategic illnesses, those that are highly prevalent, complex, and high-risk, and therefore lead to premature death and disability among affected individuals. This is the case with cardiovascular disease, which is one of the key causes of death worldwide,” he explains.

Avezum’s research brings together some of the key characteristics shared by almost all Brazilians among the most cited. In addition to working on topics associated with some of the most urgent and complex issues of the 21st century, their research has produced comprehensive data that is suitable for inclusion in global abstracts. These include revision or observational projects undertaken in different countries with the goal of analyzing the same phenomena in integrated ways. It is not by chance, but rather common, that these researchers are part of large collaborative networks in Brazil and abroad. One of the most cited works of Barros and Victora—curves of fetal growth—was realized in the context of a large collaborative network, the International Fetal and Newborn Growth Consortium for the 21st Century. “The capacity of researchers to respond to complex questions and produce internationally relevant knowledge requires that they collaborate with highly productive groups,” identifies physician Luis Augusto Rohde, of the Psychiatry Department at the Federal University of Rio Grande do Sul (UFRGS), and one of the most cited Brazilians in 2020. “The partnership we have had for at least 20 years with Barros and Victora’s group in studies about mechanisms of molecular genetics, epidemiology, clinical phenomenology, as well as pharmacological and non-pharmacological treatments for children with attention deficit hyperactivity disorder (ADHD) has been fundamental for us to reach international renown in the area of psychology and psychiatry.

The relationship between international collaborations and high scientific impact has received support in recent studies. One of them, carried out by physicist Carlos Henrique de Brito Cruz, from the University of Campinas (UNICAMP) and scientific director of FAPESP between 2005 and 2020, involved articles with up to 10 authors and published in indexed journals at WoS between 2015 and 2017. It verified that the number of citations of Brazilian articles tends to increase when produced in collaboration with researchers abroad. “There is significant debate about whether or not international collaborations increase the visibility of articles and therefore receive more citations, or if they receive more citations because they are the result of collaborations involving large groups of elite researchers,” emphasizes Pendlebury. “We know that articles with more collaboration tend to receive more visibility and citations,” confirms Brito Cruz. “Biochemist Hernan Chaimovich and biologist Jacqueline Leta studied this with respect to Brazil in an article published in 2002 in the magazine Scientometrics. The data I collected most recently show that the same effect results when there is a limited number of coauthors. What we don’t yet know well is if collaboration arises from visibility or if visibility results from collaboration.”

There is no comprehensive response for this question. However, it is true that working in collaboration has a virtuous effect that increases, for example, access to research infrastructures. “A large part of research work in ecology of ecosystems requires analyses of different properties and components of the environment and of biodiversity, which is not always possible due to our limited resources. To circumvent this problem, it is not unusual for us to turn to partner organizations,” says Bustamante, of UnB. Partnerships also allow Brazilian scientists to obtain resources from international agencies. This is, in fact, one of the key differentiators of the Pelotas group. “More than half of the total investment in research that we’ve received in the last 40 years has come from international sources, such as IDAC (International Development Research Centre), in Canada, and from Wellcome Trust, in the United Kingdom,” says Barros, of UCPel.

This effort tends to result in published works in prestigious journals and more citations. Furthermore, a significant number of articles by highly cited Brazilians are signed by more than 10 researchers, a phenomenon that has been gaining strength in science for some time (see Pesquisa FAPESP issue no. 289). Many are master’s or doctoral students and postdoctoral researchers. “These professionals comprise an important part of the support network responsible for creating a flow for the activities in the field and laboratory and to advance the research projects,” recalls Henriette de Azeredo, of EMBRAPA. This is why there is concern over recent reductions in investment in science and technology, and fewer post-graduate scholarships. “Clarivate’s numbers reflect the investment in research undertaken in the last two decades. We don’t yet have an understanding of the impact the cuts in recent years will have on Brazilian scientific production in this new decade.”

Prolonged impact

The Clarivate list, distributed in November, is combined with another study published in October in the journal PLOS Biology. Based on information from the Scopus database of the Elsevier publishing house—an international group of researchers—under the supervision of physician John Ioannidis, of the Department of Epidemiology and Public Health at Stanford University in the United States, developed a ranking of the most influential scientists in the world in 22 scientific fields and 176 subfields. It was done according to indicators of multiple citations—citations, self-citations, number of published articles, index of coauthorship and citations of articles in different levels of authorship—tracked between 1996 and 2020: 161,441 researchers were considered, of whom 853 are Brazilian, linked to various teaching and research institutions. USP, the largest university in Brazil, stands out again as the institution with the most researchers among the most cited—164—including biologist Jean Paul Metzger, of the Institute of Biology, in the area of evolutionary biology, Paulo Artaxo, of IF, in atmospheric sciences, and Fernando de Queiroz Cunha, manager of the Research Center for Inflammatory Diseases, one of the Research, Innovation, and Dissemination Centers (RIDC) that is supported by FAPESP, in the area of pharmacology and pharmacy.