Bmc Medical Research Methodology Open Access New Journal Selection for Quantitative Survey of Infectious Disease Research: Application for Asian Trend Analysis

Background: Quantitative survey of research articles, as an application of bibliometrics, is an effective tool for grasping overall trends in various medical research fields. This type of survey has been also applied to infectious disease research; however, previous studies were insufficient as they underestimated articles published in non-English or regional journals.


Background
Quantitative survey of research articles, as an application of bibliometrics, is an effective tool for grasping overall trends and productivity in various medical research fields, such as genetic epidemiology [1], radiological research [2,3], non-communicable disease research [4], tropical medicine [5], public health [6,7], dermatology [8], gastroenterology and hepatology [9], pediatrics research [10], and so on. Additionally, comprehensive analyses of research productivity in the field of biomedical research have been reported [11][12][13][14]. The results of analysis contribute to provide the information needed for decisionmakers dealing with a specific subject, public policymakers, researchers and business leaders [15]. Also in the field of infectious disease research, quantitative survey to understand study trends on the prevention, detection, diagnosis, and treatment of diseases is an advantage for formulating further research strategies, linked to perspective national and international policies for disease control. Given that there have been frequent outbreaks of various severe emerging infectious diseases, as pandemic (H1N1) 2009 and human cases of H5N1 avian influenza [16,17], such overall analysis of studies has become important.
In the field of infectious disease research, articles about specific infectious diseases, such as Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS), have been quantitatively analyzed [18][19][20][21]. Meanwhile, there are relatively few comprehensive analyses of all infectious disease research; only several previous studies on the EU [22][23][24] and specific world regions, including Japan [25][26][27]. These studies demonstrated the trends on infectious disease research, in viewpoint of the relation to gross domestic product (GDP) [22][23][24]27], gross national income (GNI) [26], share of research articles [25] and the impact factor (IF) [26], which was developed by Thomson Reuters to quantify citations of scientific journals [28]. However, these studies were limited regarding the collection of research articles as they tended to collect more international English research articles than regional or non-English papers. Articles published in regional journals, particularly Asian journals, should be further analyzed because many outbreaks of emerging infectious diseases, such as severe acute respiratory syndrome (SARS), Nipah virus infection, and human cases of H5N1 avian influenza, have been reported in Asian countries [29] and demand for the control of such diseases might be rising among scientists in these countries. Nonetheless, studies on overall research trends across Asia have not been reported, regardless of specific approaches such as HIV/AIDS research in India [30], tuberculosis research in India and China [31] and Japan's share of articles published in 7 journals, which were con-sidered to have the high IF in the field of infectious disease research [25].
Asian research trends have not been sufficiently analyzed because of limitations regarding journal selection for a survey of research articles. One of the reasons is that several previous analyses [22,[24][25][26][27] relied on journals registered in the 'Infectious Disease Category' of the Science Citation Index Expanded™ (SCI Infectious Disease Category) [32]. The SCI Infectious Disease Category covers the major journals in the field of the research, however, the vast majority of journals in the category are produced in English [22]. Another reason is that Asian regional journals, particularly in their native languages, tend to be less cited by English-speaking researchers because of the extra effort of translation. This bias possibly disadvantages researchers in Asia, whose study results are published in not only international journals but also their regional journals. Therefore, in order to closely analyze Asian trends in infectious disease research, a new approach with the potential to survey a wide range of journals should be developed.
The objective of this study was to demonstrate a new journal selection applicable to widely survey infectious disease research articles, with less bias among countries and regions. Using these journals, we also experimented with quantitative analysis to understand the trend in infectious disease research in Asia.

Methods
The following steps correspond to Figure 1.

Step 1-Adoption of data source
In this study, we applied the Scopus™ database [33] as a source to select journals on infectious disease research (infectious disease journals). This is a new abstract and citation database of the scientific literature provided by Elsevier B.V., which includes over 16,000 peer-reviewed journals.
Step 2-Screening of journals On the basis of the Scopus™ database (registered in January 2008), we screened infectious disease journals, using English keywords directly linked to disease control in detection, prevention, diagnosis and medical care (A-E). The keywords intended to select journals specifically focusing on infectious disease (A), corresponding to general or categorical infectious diseases (B), in the field of clinical microbiology (C), regarding the development of medicine (D), and intended for overall technology development for disease control (E). Additionally, we selected related journals in the field of public health on the basis of our experience (F).
In parallel, we screened non-English journals, using Japanese, Chinese, French, German, Italian, Spanish, and Turkish keywords corresponding to the keywords in A-E (details shown in the legend to Figure 1). To screen Korean journals, we used English keywords, because almost all journal titles (89 of 91 journals) were registered in English, or both English and Korean (in Roman letters) in the Scopus™ database. In the survey with English and non-English keywords, we introduced an approach based on both partial matching (for a search of journal titles that contain the keywords) and complete matching (for a search of titles that perfectly matches the keywords) to capture journal titles involving inflected forms of the keywords.

Step 3-Selection of journals
After screening the journals in Step 2, we finally selected journals in which original or review articles were included in the PubMed database provided by the U.S. National Library of Medicine [34] from 2006 (articles published in 2007 can be seen in the database) because we emphasized the further usability of our survey method: the PubMed database is freely accessed and widely used, and the selected journals have continued in print.
Framework for quantitative analysis of infectious disease research Figure 1 Framework for quantitative analysis of infectious disease research. *All keywords in A (except for HIV), infection, infectious disease, communicable disease, sexually transmitted disease, and zoonosis in B, antibacterial, antiviral, antimicrobial, vaccine, and antibiotic in D were translated into French, German, Italian, Spanish, Turkish, Chinese (in Roman letters) and Japanese (in Roman letters) in order to select journals written in non-English languages. † Journals regarding research on AIDS and HIV were selected according to the 'Infectious Disease Category' of the Science Citation Index Expanded™ [32], because several journals specializing in social-scientific and policy studies on patients could not be excluded by only the keywords 'AIDS' and 'HIV'.
Step 1 Step 2 Step 3 Step4 Journals registered in the Scopus TM database [13] Infectious disease journals (final selection)

Analysis of Asian publications Step5
Step-4 Survey of Asian research articles For quantitative analysis of infectious disease research articles of Asian origin, we surveyed the number of research articles in the above selected journals that were produced in 11 Asian countries: Japan, China, India, Taiwan, Korea, Singapore, Malaysia, Indonesia, Vietnam, Thailand, and the Philippines. We also surveyed the number of the world total as a reference.
We took advantage of the 'Limits' function of the PubMed database, which contains tags for limiting the journal name ( [35]. We targeted original articles and reviews as research articles (hereafter, research articles mean original articles and reviews); the former was considered as an indicator of research activity and the latter as an appreciation of research results. Since we considered that highly valued scientists were given more opportunities to write reviews, meaning that their research results had attracted a good opinion and had relatively good qualities, we targeted not only original research articles, but also reviews. Based on the thought that the number of reviews might be indicative of research quality, it was surveyed separately from the number of original articles.
Concerning the publication date, we prioritized the print date for journals that had both print and electronic versions; for example, we used the following text to search for research articles published on 'AIDS' during 1998-2006 and whose first author was in Japan:

AIDS [Jour] AND journal article [pt] AND Japan [ad] AND 1998:2006 [PPDAT].
Additionally, we compared the number of research articles registered in the selected journals to those in the SCI Infectious Disease Category during the period, to ascertain whether the newly selected journals were appropriate to survey a wide range of articles in the field of infectious disease research. We surveyed articles registered in the SCI category in a manner similar to those in the above selected journals.

Step-5 Analysis of Asian publications
In order to evaluate socioeconomic factors associated with Asian publications, we weighted the number of research articles registered in the newly selected journals during 1998-2006 according to the population and the gross domestic product (GDP) of each country. We obtained annual data for the population and GDP from the online database of the United Nations [36] for Asian countries. Regarding Taiwan, we used the data from the Taiwan Statistical Data Book 2008 published by the Taiwan's Council for Economic Planning and Development [37]. Using the non-parametric correlation statistical test (Spearman's Rank Correlation test), the numbers of research articles were analyzed in relation to the population and GDP. Statistical analyses were performed using PASW Statistics (version 17.0; SPSS Japan Inc., Tokyo, Japan).

Journal selection
To screen infectious disease journals (Step 2 of Figure 1), 264 candidates were selected (see the actual journals in Additional file 1), of which 240 were selected by English key words and 24 by non-English words. The 264 journals were published in 30 countries and written in 12 languages: English, Japanese, Chinese, Korean, French, German, Italian, Spanish, Turkish, Polish, Russian, and Croatian (see 'Language used' in Additional file 1). Subsequently, we selected 100 of the 264 journals, based on the usability of the PubMed database (Step 3 of Figure 1, see Table 1 and gray labeled journals in Additional file 1). The 100 journals were published in 18 countries and written in English or 7 non-English languages: Japanese, Chinese, French, German, Spanish, Turkish, and Russian (Additional file 2). Forty-eight of the 100 journals matched the journals in the SCI Infectious Disease Category, except for 8 journals (the journals were outside our analysis condition, see details in the legend to Additional file 2). The remaining 52 journals were originally selected in this study and included 15 Asian journals, which consisted of 3 journals in Japanese and 2 in Chinese, 7 in English, and 3 in both English and Japanese or Chinese. The breakdown of the 100 journals corresponding to categories A to F in Figure 1   100 journals was about 2.4-to 6.9-fold (Asian countries) and 1.5-to 1.7-fold (world) higher than in the SCI category.
Concerning the proportion of Asian articles relative to the world total, it was revealed that a survey of the 100 journals showed a consistently higher percentage than the SCI Infectious Disease Category during 1998-2006. The total of Asian research articles accounted for 12% of the world total in the survey of 100 journals (actual numbers of Asian and worldwide research articles were 14,156 and 118,158, hereinafter, as described in this paragraph) (Additional file 3) and 6.9% in the survey of SCI Infectious Disease Category (4,621 and 66,518) (Additional file 4). Each year during the study period, the proportion of original articles of Asian origin relative to the world total was about 8.6-14.2% in the 100 journals and 4.7-9.3% in the SCI category, and that of reviews of Asian origin was about 4.2-6.9% in the 100 journals and 1.0-3.9% in the SCI category (Additional file 3 and 4).

Asian publications in originally selected journals
Subsequently, we surveyed the number of research articles of Asian origin on a country-by-country basis, using the 100 selected journals. It was revealed that Japan had the highest percentage of articles in Asian countries, followed by China, India and Taiwan in descending order during 1998-2006 (Table 2). Additionally, Japan, India and Taiwan produced relatively large numbers of reviews in comparison with other countries (see the column 'Relative to the total number of reviews (RV) of 11 Asian countries' in Table 2). On the other hand, Singapore, Thailand and the Philippines had a high ratio of reviews in their domestic total number of research articles regardless of the relatively low ratio of reviews by Asian countries (see the column 'Relative to the domestic total number' in Table 2). Using population-adjusted ratios, Singapore (median value of 6.9) and Taiwan (6.2) were most productive (Figure 5). The ratio of the number of reviews showed a median value of < 0.1 publications/1 million population/ year (range, 0-0.5). When adjusting the production of reviews according to population, Singapore ranked first

Discussion
Our study has demonstrated that a survey method using 100 selected journals is beneficial to grasp the overall trends in infectious disease research in comparison with Number of reviews originating from Asia and worldwide Year previous bibliometric studies based on journals registered in the SCI Infectious Disease Category. This is derived from the findings that a survey of 100 journals showed not only more research articles originating from both Asian countries and worldwide, but also a higher proportion of Asian articles relative to the world total than in the SCI Infectious Disease Category. The survey succeeded in analyzing Asian trends in infectious disease research by identifying research articles published even in regional and non-English journals.
To our knowledge, the trend per Asian country was analyzed for the first time in this study. Japan was considered to be the leading country in the field of infectious disease research in Asia because it had the highest percentage of both original articles and reviews during 1998-2006 in the survey of 100 journals. Additionally, China, India, and Taiwan were assumed to have markedly elevated productivity in research, and research results from the latter 2 countries were better appreciated among Asian countries from the viewpoint of the higher rate of original articles and reviews than other Asian countries (except for Japan).
On the other hand, Singapore and Taiwan ranked high when the population and GDP were taken into account. Regarding Singapore, the analysis result is comparable to the previous report that the country ranked higher than Japan and Taiwan in the field of biomedical research when adjusting the number of publications to the population [38]. Further analysis with science and technology indicators as the number of researchers and the public expenditure on research and development, as shown in previous reports [38,39], is considered to be favorable for our study, however, such analysis was not conducted. This is because annual data from the 11 Asian countries were not fully available during the study period, even using the databases of international organizations such as the Main Science and Technology Indicators of the OECD [40] and the Science and Technology Indicators of the ASEAN STI/ TCI [41].
Regardless of improved journal selection, as described above, our method has several methodological limitations. First, the keyword setting for journal selection has limitations; the 100 newly selected journals are not equivalent to existing full infectious disease journals. This is attributed to the fact that we set representative keywords for journal selection in several languages used by many people throughout the world, but did not cover all the keywords related to infectious diseases research. Additionally, our procedure for journal selection was not entirely automated, requiring not only keywords, but also professional judgment (see Figure 1F). Given these observations, our method may be difficult to generally apply to a survey of infectious disease research around the world; however, we think that our journal selection has demonstrated the prospect for a more exhaustive survey of infectious disease research.
Concerning the keyword setting for journal selection, our method has another limitation. Since we selected 100 journals on the basis of keywords directly linked to infectious disease control, we missed articles published in gen- eral scientific and medical journals, such as 'Nature', published by the Nature Publishing Group, and 'Science', published by the American Association for the Advancement of Science (AAAS), and general medical journals, such as the 'New England Journal of Medicine', published by Massachusetts Medical Society. This limitation of journal selection might be common because this disadvantage was also noted in the previous study [22]. However, we believe that the number of missed articles did not significantly affect our study results because our survey scheme was designed to understand the overall trends in infectious disease research by obtaining the relative numbers of research articles per country or region, not to strictly count the absolute numbers of articles.
An additional limitation relates to the survey of author affiliation in the PubMed database. Since we based the affiliation on country name, we missed research articles whose author's affiliations were recorded as the names of the city, district, university or institution (not country). The reason comes from the fact that such articles were reported previously [12,26,42] and additional articles could be retrieved by applying names of cities and institutions in a country [12,42]. However, we think that the preference for country name as the author affiliation is appropriate as far as this study goes because research articles originating from each Asian country should be counted under fixed condition for an international comparison of research productivity. Moreover, it is difficult to establish sufficient names for a city or institution; taking Japan as an example, there are numerous research institutions, universities and other organizations engaged in research on infectious diseases across the country. That said, as further issues, we should develop a setting for author affiliation corresponding to various countries and regions.
As further issues, our study should introduce qualitative analysis of infectious disease research articles, based on two viewpoints. One intends to survey the content characteristics of the disease research, such as targeted diseases, methodology used (epidemiological, pathological, etc.) and so on. The analysis will contribute to grasping the outline of the research outcome and formulate a further strategy for research. The other is designed to analyze the scientific quality of the research. As an effective and valuable method for analyzing scientific quality, a measurement of the IF has been applied globally; nevertheless, the measurement is considered to have an English language bias [43]. On this basis, the current method of IF measure- Malaysia Philippines Indonesia Thai ment might be poorly adapted for qualitative analysis of regional and non-English journals; therefore, a new method for expanding the versatility of qualitative analysis should be developed hereafter.

Conclusion
We present a new journal selection to survey articles of infectious disease research. The 100 selected journals contribute to quantitative survey of research articles in not only international, but also regional and non-English journals, with little bias among countries and regions. We suggest that surveying these 100 journals is more beneficial than the SCI Infectious Disease Category, because it identifies more research articles and avoids underestimation of the numbers of articles in regional and non-English journals. Our survey method may require further development; nevertheless, the method provides an effective tool for grasping overall trends in infectious disease research around the world.