Bibliometric analysis of Ghana publications in the Science Citation Index Expanded

Ghana is a West African country for which apparently there are limited scientometric studies. The objective of this study was to analyze the Ghanaian contribution to knowledge captured in the Thomson Reuters Science Citation Index Expanded (SCI-EXPANDED) database from 1936 2016. The following data were analyzed: document type, the language of publication, publication trend, Web of Science Subject Categories, Journals, international collaboration, institutions, authors, and highly cited articles. Indicators such as the total number of articles, first author articles, and corresponding author articles were applied to compare publication performance for collaborative countries and institutions. Also, number of single institute articles: number of nationally collaborative articles: number of internationally collaborative articles (S : N : I) were also used to compare publication characteristics of institutions in Ghana. Results showed that publication trend increased from 1998 to 2015, with researches focusing on health and medicine. PLoS One was the top productive journal, and the most collaborative country for Ghana articles was the USA. Contributions from the University of Ghana were ranked the top one institution for Ghana articles, and higher citation papers were found in international collaborations. In conclusion, the contribution to knowledge of Ghanaian authors is massive in the areas of public, environmental and occupational health and tropical medicine but the impact factor is higher for immunology, infectious diseases, and microbiology articles. Therefore, Ghanaian authors are encouraged to publish more articles in high impact factor journals with Thomson Reuters Scientific indexing in order to have their researches recognized by the existing international databases. Rev. Biol. Trop. 66(1): 106-121. Epub 2018 March 01.

Science Citation Index (SCI) was known in the science community in 1955, and it is currently the cutting-edge tool to facilitate the dissemination and retrieval of scientific literature (Garfield, 2006).The SCI's multidisciplinary catalogue is to achieve two objectives: i) to identify what each scientist have published, and ii) where and how often the papers by the scientist are cited (Garfield, 2007).For this reason, the author-based part in SCI journals is divided into the Source Author Index and the citation index.By inference, one can also determine what each institution and country has published, and how often their papers are cited.Web of Science (WoS) which is the SCI-EXPANDED's electronic version can link the source author index and the citation index, and this way, author's publication can be listed by chronology, by the journal, or by citation frequency using WoS.Furthermore, it is possible to search for scientists who have published over a given period of years using the mentioned tool (Garfield, 2009).Based on the above realization, scientists have embarked on bibliometric analysis to understand the nature and complexity of research activities.
Bibliometric analysis is therefore defined as the quantitative study of science, communication in science, and science policy (Sam, 2008;Milojević & Leydesdorff, 2013).It has been employed universally for quantification and assessment of the research output of researchers, research institution, academic institutions and countries (Aswathy & Gopikuttan, 2013;Noruzi & Abdekhoda, 2014).Generally, bibliometric analysis results are used for ranking, awarding, budgeting, and defining research priorities (Fakhree & Jouyban, 2011).Intellectually, publications are often regarded as those that the writers have in its scholastic, or the intellectual society and their publications are managed by renowned bodies with academic ambitions and task (Alemna, 2016).It additionally mentions that learned publications do not only offer research results thereby moving forward new facts, but their contents are subjected to careful inquiry by professionals in a given field.
Recently, peer-reviewed journals using Thomson Reuters Scientific indexing services have since become accepted as definitive evidence of research endeavors of scientists all over the world (Nwagwu & Egbon, 2011).The authors mentioned that the position of science in Africa has always been queried.They posed the following questions in their paper: i) Do scientists in Africa do research?, ii) Where and in what journals are their researches published?, and iii) What is the quality of the journals where these publications appear?Frankly, responding to the above queries require the availability of detailed evidence of research from the country in question.On the other hand, local databases infrastructures to give this picture do not exist, and current international databases are also unfair in the source selection processes.They generally leave out a lot of research outputs of researchers from the developing regions (Nwagwu & Egbon, 2011).This has gingered researchers from Africa to publish in journals with Thomson Reuters Scientific indexing services, in order to have their researches recognized by the existing international databases, and this has been executed perfectly well via research collaboration.
The whole of Africa's research collaboration pattern, both regarding countries and cities, has been distinguished into three separate scientific regions, namely Northern, Western, and Southern-Eastern (Toivanen & Ponomariov, 2011).For comparison purpose, Africa's contribution to the worldwide research literature has been computed (Tijssen, 2007).The scientific production component in the Southern Africa Development Community (SADC) was dealt with in this literature (Pouris, 2010).It was found in the literature that South Africa is responsible for 79 % of the regional production (Pouris & Pouris, 2009).They reported the results of an effort to calculate scientometric indicators-research publications and patentsfor the African Continent, compared them with those of other regions and discussed their implications.Collaboration ties in Central Africa's scientific output revealed that colonial and cultural ties play a major role in the international collaboration (Boshoff, 2009).Further research dealt with collaboration among the SADC countries as well as with the rest of Africa.It was concluded that South Africa acted as the political North, i.e., it dominated the regional scientific research (Boshoff, 2010).
Latest research works on bibliometric studies in Ghana include: Research focus and trends in nuclear science and technology in Ghana: A bibliometric study based on the INIS database (Agyeman & Bilson, 2015); a scientometric analysis of research performance of Ghanaian polytechnics (Lomatey, Abledu, Baayel, Akussah, & Botchway, 2016); research collaboration in Ghana: patterns, motives and roles (Owusu-Nimo & Boshoff, 2017).However, among these bibliometric studies presented so far, there is no comprehensive bibliometric analysis of Ghana publications in the Science Citation Index Expanded (SCI-EXPANDED) from 1936-2015.This research will, therefore, provide the following: names of authors, title, year of publication, source journals publishing the articles, contact address, and each year citation times for every publication in SCI-EXPANDED.

Science Citation Index Expanded (SCI-EXPANDED) of Web of Science Core
Collection of Thomson Reuters was used to collect the bibliographic data (Data last updated: July12th, 2016).An advanced search was conducted for documents with the phrase "Ghana" in the country field.Initially, 9 364 publications were identified, and these documents were published between 1958 and 2015.Document information included names of authors, title, year of publication, source journals publishing the articles, contact address, and each year citation times for every publication were downloaded into Microsoft Excel 2013, and additional coding was manually performed for origin country and institute of the collaborators, and impact factors of the publishing journals (Li & Ho, 2008).Besides, the reported impact factor (IF 2015 ) of each journal was obtained from the 2015 Journal Citation Report (JCR).The total number of times a document cited from the Web of Science Core Collection since its publication to the end of 2015 was recorded as TC 2015 (Chuang, Wang, & Ho, 2011;Wang, Fu, & Ho, 2011).Likewise, C 2015 , the total number of citations of a paper in 2015 only (Ho, 2012) were employed to characterize Ghana publications.Also, the citations per total publications (TP) since publication (CPP 2015 = TC 2015 /TP), was also used (Ho & Ho, 2015).Articles originating from England, Scotland, Northern Ireland, and Wales were reclassified as originating from the United Kingdom (UK).Affiliations in Hong Kong before 1997 were included in the China category, but as a separate region for consistency.Affiliations in Federal Republic of Germany (Fed Rep Ger), West Germany, Germany Democratic Republic and East Germany were checked to be in Germany (Ho, 2012) (Chuang, Chuang, Ho, & Ho, 2011).Affiliations in UKSSR were checked to be in Ukraine.Affiliations in Czechoslovakia were checked to be in Czech Republic (Czech Republic) (Ho, 2013).Affiliations in Greenland were checked to be in Denmark.
The lucid dominance of full articles over other types of documents was not shocking, since Ghanaian researchers/lecturers are promoted based on number of full articles published in refereed journals and working experience.This enhances the salaries of the researchers, thus discouraging other types of work such as meeting abstracts, letters, editorial materials, reviews, proceedings papers, and notes.
An internationally collaborative review entitled "Allergic rhinitis and its impact on asthma (ARIA) 2008" (Bousquet et al., 2008) by 96 authors from 99 institutions in 40 countries was the most cited review with TC 2015 of 1 316.This is the only one review with TC 2015 > 1 000 in Ghana.Similarly, an editorial material entitled "Malaria: current status of control, diagnosis, treatment, and a proposed agenda for research and development" (Guerin et al., 2002) by nine authors from seven institutions in six countries was the most cited editorial material with TC 2015 of 196.
Altogether, 7 375 articles were extracted from the 9 364 documents for further analyses.Almost all articles were published in English (7 358 articles; 99.76 % of 7 375 articles), 10 in French and seven in German.Nearly all Ghanaians speak English because Ghana was colonized by the British, and that is reflected in the number of papers published in English.The second reason for publishing in English was to reach a wider readership (Monge-Nájera & Ho, 2012).French was the second largest group of publishers (0.14 %) and this was not shocking, because Ghana is surrounded by three Francophone countries such as Togo, Burkina Faso, and Ivory Coast.The third largest group was German (0.10 %), which reflects the number of Ghanaian researchers who obtain their university degrees from the Federal Republic of Germany due to important scholarships such as DAAD and KAAD.

Publication year:
In order to study publication year, total number of articles (TP), number of authors (AU), number of cited references (NR), and their averages were captured in accordance with Ho's group publications (Ho, 2007;Wambu & Ho, 2016).Characteristics of Ghana articles in SCI-EXPANDED from 1958 to 2015 are shown in Table 1.A total of 7 375 Ghana articles were published in journals listed in SCI-EXPANDED, with an average of four authors in a publication.Total number of papers was in single digit from 1958-1971, and it rose to double digits from 1972-1995 and finally to triple digits from 1996-2015.The increase in the number of papers in SCI-EXPANDED journals by Ghanaian authors could be as a result of teaching and research institutions existence in Ghana as well as the local and international financial support.
In recent years, Ho proposed a relationship between classic articles and their citations per publication (CPP year = TC year /TP) by years (Ho, 2013).It was also applied to highly cited publications in Taiwan (Chuang & Ho, 2015) and publications in dance field (Ho & Ho, 2015).Fig. 1 shows the mentioned relationships which   Vowell harmony" (Stewart, 1967).This was not surprising at all because it was mentioned in the paper that the Akan (Twi-Fante) language shares with a multitude of other African languages a type of vowel harmony which is apparently found nowhere outside Africa.Also, the vowels of these languages always, it seems, fall into two harmonizing sets, one of which has relatively high and the other relatively low tongue positions, and consequently many writers have seen relative tongue height as the articulatory basis of the harmony.Furthermore, our search shows that the Akan language is studied in major universities in the United States, including Ohio University, Ohio State University, University of Wisconsin, Harvard University, Boston University, Indiana University, Michigan University, and The University of Florida, and this could have also attributed to extremely high CPP 2015 that was found in 1967.

Web of Science subject categories and journals:
To study Web of Science subject categories, we followed literature which focuses on a country (Monge-Nájera & Ho, 2012& Ho, , 2015)).According to Journal Citation Reports (JCR) in 2015, there were 177 Web of Science categories in SCI-EXPANDED.Ghana articles were published across 173 Web of Science categories, but no articles in categories of andrology (5 journals), microscopy (10 journals), neuroimaging (14 journals), and ocean engineering (14 journals).Fig. 2 shows top 15 productive categories and number of journals in each category.Category of public, environmental and occupation health, had the highest total articles (976) followed by tropical medicine (780) and then environmental sciences followed with 543.Authors in Ghana were active in tropical medicine in which there were only 19 journals.Similarly, tropical countries in Central America, for example, Nicaragua   2 were in the Web of Science category of public, environmental and occupational health.Four journals were in category of tropical medicine.This was not surprising since most of the avid Ghanaian writers were with the health research institutions.Researchers in the medical field were able to attract funding from local and international donors, and they are required to publish their findings in SCI-EXPANDED journals with wider readership.
International collaboration: In total, 5 038 Ghana articles (68 % of 7 375 articles) were internationally collaborative articles with 172 countries.Table 3 shows the distribution of the top 20 collaborative countries with Ghana.The most productive countries according to the number of published articles in collaboration with Ghanaian researchers were USA and UK, but there were more published articles by Ghanaian researchers with USA researchers playing the leading role (FP and RP).However, percentage of articles with leading role by Ghanaian researchers is pretty low for all shown countries.It is worth noting that South Africa being an African country, was the fifth country among the top 20 collaborative countries for Ghana articles in the Science Citation Index Expanded (1958~2015) (Table 3).Among the top 20 countries only Burkina Faso shares boundary with Ghana.More collaboration with non-adjacent countries such as USA and UK than neighbouring countries can be explained with economic and social development, research and development expenditure of these countries (Owusu-Nimo & Boshoff, 2017).Also, most researchers from Ghana went to American and European universities to study, and that accounted for the high collaboration with those countries (Monge-Nájera & Ho, 2012).

Institutions:
The national (590 articles; 8.0 % of 7 375 articles) and internationally collaborative articles (5 038; 68 %) with Ghana were considered as the inter-institutional collaboration (5 628; 76 %).Indicators such as total number of articles, TP, first author articles, FP, and corresponding author articles, RP, have been presented to evaluate publication performance (Wang, Yu, & Ho, 2010).Furthermore, an indicator SNI, a proportion of single institution articles: nationally collaborative articles: internationally collaborative articles (S:N:I) was applied to compare and describe institutions' publication characteristics (Ho & Fu, 2016).Table 4 shows the top 10 institutions for Ghana articles in the Science Citation Index Expanded.Researchers affiliated to those ten institutions published 69 % of all 7 375 analyzed articles.University of Ghana took the first position in indicators of TP, FP, and RP.The University of Ghana is the oldest university in this country, and one of the first to have been established in West Africa; it was established in 1948 and now offers degree programmes on varied broad disciplines such as health sciences, engineering sciences, natural sciences, nuclear and allied sciences, agricultural sciences, humanities, law, business, social sciences and performing arts.During the period 1958-2015, University of Ghana published 36 % of the analysed Ghana articles, 32 % of the first author articles, and 31 % of the corresponding author articles.The second place by TP, FP, and RP indicators was taken by Kwame Nkrumah University of Science and Technology.
In Ghana, the proportion of S:N:I was 24:8.0:68.University of Ghana's proportion of S:N:I was 23:12:65.University of Science and Technology was able to conduct research independently with S:N:I = 51:6.4:42.Ghana Atomic Energy Commission had more national teamwork or collaboration among different institutions with S:N:I = 20:34:46.In Table 4, only University of Science and Technology (S:N:I = 51:6.4:42)had at < 50 % internationally collaborative articles of its total publications.Ghana Health Service had the highest percentage of international collaboration with S:N:I = 2.5:8.0:89.Our search showed that this trend was expected, because it agrees with the core functions of Ghana Health Service.The core functions of Ghana Health Service include the following: i) The analysis of national, bilateral and international policies and their application in the development of strategic plans and implementation guidelines for the Ghana Health Service in collaboration with other Divisions and implementation partners; ii) the coordination, guidance and development of short, medium and long-term plans and budgets for the Ghana Health Service's development, including the preparation of projects and programmes for local and international financing consistent with the Sector-Wide/Multi-Donor Budget Approach; and iii) the development of level specific performance indicators and contracts consistent with national, bilateral and international expectations, among others.based institutions and this could be due to the financial support they generally receive from both local and international donors for cuttingedge research.
Highly cited articles: This section captures Ghana articles including total number of times each article was cited from the Web of Science Core Collection since its publication to the end of 2015 (TC 2015 ), total number of citations of a paper in 2015 only (C 2015 ), and the number of authors (AU).Table 6 shows the top 11 Ghana articles with more than 300 citations (TC 2015 > 300).The 11 articles were all of international collaboration.Both first and corresponding authors were not from Ghana.Seven first authors were from USA, three from the UK, and one from Australia while eight corresponding authors from USA and three from the UK.The article titled "Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010" (Lozano et al. 2012) was published in Lancet by 189 authors and was ranked first for TC 2015 .The second position was occupied by the article titled "Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010" (Murray et al., 2012) also published in Lancet by 359 authors.It is clear from Table 6 that the top three most cited articles were all published in a high impact factor journal (i.e.Lancet).This was expected because it is known in literature that papers published in journals with a high IF would probably have high citations (Chuang & Ho, 2015).Furthermore, the article titled "Impact of permethrin impregnated bednets on child mortality in Kassena-Nankana district, Ghana: A randomized controlled trial" (Binka et al., 1996) was the most frequently cited article with TC 2015 of 260 by F.N. Binka from Navrongo Health Research Centre as the first and also corresponding authors.
In conclusion, Ghanaian researchers/lecturers should publish their scientific works in high impact factor journals captured by Thomson Reuters to have high citations.
Palabras clave: Ghana; SCI-EXPANDED; Web of Science; tendencias de investigación; colaboraciones indicate that there is no significant change in the first periodfrom 1958 to 1972 and 1973  to 1996, respectively.In 1958, T. W. Tinsley and co-workers from West African Cocoa Research Institute in Ghana published three earliest Ghana articles about viruses and cacao in Annals of Applied Biology(Attafuah & Tinsley, 1958;Knight & Tinsley, 1958;Tinsley & Wharton, 1958).In the third period from 1997 to 2015, publication trend increased from 123 articles to 794 articles.The significant increase in publication trend in the third period was expected, because most of the research-performing institutions in Ghana were established after the independence, and that accounted for the increase in the publication trend(Owusu- Nimo & Boshoff, 2017).The CPP 2015 for 7 375 Ghana articles was 13.An extremely high CPP 2015 was found in 1967 with 44, attributed to the only one article in 1967, entitled "Tongue root position in Akan

Fig. 1 .
Fig. 1.Number of total articles and citations per publication.
(Monge-Nájera & Ho, 2017a) and Honduras (Monge-Nájera & Ho, 2017b) also published the most articles in category of public, environmental and occupation health, but Costa Rica (Monge-Nájera & Ho, 2012) and Panama (Monge-Nájera & Ho, 2015) paid more attention to plant sciences.In total, 7 375 Ghana articles were published in 1 917 journals in SCI-EXPANDED.Table 2 shows the distribution of articles in the top 10 journals.The value of the indicator IF 2015 for each journal was obtained from JCR for 2015.The journal with the most published articles was PLoS One which published 193 articles, 2.6 % of all analyzed articles.PLoS One fell into the category of multidisciplinary sciences and had an IF 2015 of 3.057.The second position was Malaria Journal with 141 published articles (1.9 %) in Web of Science

Fig. 2 .
Fig. 2. Top 15 Web of Science categories of Republic of Ghana's publications.

limited
Information and Communication Technologies (ICTs), the lack of leadership mandate and support, the lack of congenial political and academic environment in some countries, shortage and lack of faculty to pursue academic research due to heavy teaching loads and inadequate financial support.Furthermore, Table5 listedindicators including total number of articles, number of article with first author, number of article with corresponding author and number of single author articles, for the top 11 productive authors, each with 60 or more articles.S. Owusu-Agyei, an epidemiologist with extensive experience in the design and conduct of clinical and field intervention trials from Ghana Health Service was ranked first with 125 articles, twenty-first with ten articles as the first author and twenty-second with 10 articles as corresponding author.He has been the Director of the Kintampo Health Research Centre (KHRC) since 2002.He is a part-time Lecturer in the Departments of Epidemiology and Population Health and Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine (LSHTM) and a Senior Lecturer at the School of Public Health, University of Ghana, Legon.The second position was occupied by B. J. B. Nyarko, Director-General from Ghana Atomic Energy Commission with 77 articles, 32 nd with nine articles as the first author, 28 th with nine as the corresponding author.The third position was occupied by A. Hodgson from Navrongo Health Research Centre with 75 articles, 428 th position with two articles as the first author, 645 th position with one paper as the corresponding author.It was not surprising that the top three spots were occupied by prolific writers from research

Fig. 3 .
Fig. 3. Distribution of articles by Ghanaians authors.TP: total articles.Not FP+RP: both first and corresponding authors are not from Ghana.Not RP: corresponding author is not from Ghana.Not FP: first author is not from Ghana.IC: internationally collaborative papers.NC: nationally collaborative papers.II: institutional independent papers.CI: Ghana independent papers.FP: first author is from Ghana.RP: corresponding author is from Ghana.FP+RP: both first and corresponding authors are from Ghana.

TABLE 3
Top 20 collaborative countries for Ghana articles in the Science Citation Index Expanded (1958~2015) CP: internationally collaborative articles with Ghana; CPR (%): rank of internationally collaborative articles and percentage; FPR (%): rank of article with first author and percentage; RPR (%): rank of article with corresponding author and percentage.

TABLE 5
Top 11 authors for Ghana articles in the Science Citation Index Expanded.Only authors with at least 60 articles