Occupational therapy (OT) is one of the allied health professions practiced globally. Research and research publications are an integral part of the OT profession. “Archives of Occupational Therapy” was the first published OT journal published in 1922 ( Cruz et al., 2019). In the 21 ^st century, most of the journals became online web-based after the invention of the internet ( Cruz et al., 2019). There are thirty-nine journals published that have contained “occupational therapy” in journal-title available online. Thirty-two among those journals are published in the English language ( Cruz et al., 2019). These journals are core OT journal that mainly publishes OT-related articles. With the advancement in electronic databases and the online availability of periodicals, the newer bibliometrics and scientometrics methods of journal evaluation or evaluation of research measures are evolved ( Meho and Yang, 2006). Citation analysis and content analysis are two commonly used methods of bibliometric analysis ( Wallin 2005; T. Brown, Gutman, Ho, et al., 2018). This method is proven to examine the impact or influence of published articles, journals, researchers, institutions, and countries. Further, this method evaluates the performance in micro-level such as institution/university performance to macro-level such performance of a particular profession in research and country-wise research evaluation ( Wallin 2005; T. Brown, Gutman, Ho, et al. 2018).

Content and citation analysis is a common practice in bibliometrics of occupational therapy. In the past, most of the content analysis was performed for specific OT journals such as the American Journal of Occupational Therapy (AJOT) ( Ottenbacher and Short, 1982; Ottenbacher and Petersen, 1985), Canadian Journal of Occupational Therapy (CJOT) ( Ernest, 1983), Australian Occupational Therapy Journal (AOTJ) ( Trevan-Hawke, 1986; Madill et al., 1989), British Journal of Occupational Therapy Journal (BJOT) ( Cusick, 1995; Mountain 1997) and Occupational Therapy Journal of Research (OTJR) ( G. T. Brown and Brown, 2005). Pearl et al. (2014) evaluated and reported the content of five occupational therapy journals as AJOT, AOTJ, BJOT, CJOT, and Scandinavian Journal of Occupational Therapy (SJOT).

Most of the reported studies were based on the cited journal analysis, that is, analysis of what OT journals articles cited from other journals ( Johnson and Leising, 1986; Roberts, 1992; Reed, 1999; Potter, 2010). Recently, Nowrouzi-Kia et al., (2018) evaluated top publications with more than 100-citations in occupational therapy. This study was the first to uncover the highest annual citation rates, randomised control trials, literature reviews, and cross-sectional studies in occupational therapy.

Ziviani and colleagues (1984) analysed the content and citation of three OT journals, AJOT, BOTJ, and AOTJ. It was the first bibliometric study examining both content and authority in the OT field. In the recent past, bibliometric studies have become a popular method to know the publication trends, find researchers/authors in a particular topic, and identify research journals where prospective authors select to publish their manuscripts. This type of study helps identify the publication landscape of a specific profession ( MacDermid et al., 2015). These data are also used as criteria for research promotion, researcher incentivizing, grant allocations, and policymaking. Further, these data can also be used to benchmark faculty, department, and institute or research organization ( T. Brown et al., 2019).

Several studies were reported on the performance of OT researchers. Those studies evaluate OT authors' publication output in terms of their content and citations impact. All analyses were conducted for OT authors from specific geographical locations such as Canada ( MacDermid et al., 2015), Brazil ( Folha et al., 2017), the United Kingdom ( T. Brown, Ho et al., 2018), and Australia ( T. Brown, Gutman, and Ho, 2018). Recently one study reported the bibliometric analysis for authors of western countries and Asian countries. It includes a total of nine countries among them, United States (US), Canada, the United Kingdom (UK), and Australia were included as countries of the west, and Hong Kong, Japan, Taiwan, Singapore, and South Korea were included as Asian countries ( Man e t al., 2019). Among those few publications, it was observed that OT authors had published a high number of publications in non-OT journals ( MacDermid et al., 2015; T. Brown et al., 2017; T. Brown, Ho, et al., 2018; T. Brown, Gutman, and Ho, 2018). A good percentage of highly cited OT papers, also published in non-OT-specific journals ( Man et al., 2019). Another study on OT-publication in non-OT journals for 2004 to 2015 found publication in non-OT journals increased by 173% ( Folha et al., 2019). Because there has been an explosion of new online electronic journals with open access options for publications, publishing is a multidisciplinary type of journal that has become the global trend by prospective authors in any discipline.

Recently all bibliometric studies in the field of OT used Journal Citation Report (JCR) matrices and Journal Impact Factor (JIF) for their analysis provided by Web of Science (WOS) ( T. Brown, Gutman, Ho, et al., 2018; MacDermid et al., 2015; Gutman et al., 2017; Augusto De Araujo et al., 2017; T. Brown et al., 2017; T. Brown et al., 2019; T. Brown, Gutman, and Ho, 2018; Man et al., 2019). JIF is calculated by a simple mathematical formula, where the total citations will be in the numerator and the citable item as the denominator for the previous two years. The denominator creates confusion because the authors cite anything from the available literature, and journals do not label the publications as citable items in their author guidance. Neither prevents any kind of item for citing ( Fernandez-Llimos, 2018). Similar to JIF, Scopus CiteScore also use citation analysis for ranking journals. The Scopus database that provides CiteScore is among the two databases accepted worldwide. The other is Web of Science (WOS), which provides JIF ( T. Brown and Gutman, 2019; Fernandez-Llimos 2018; Sau, 2020).

The CiteScore metrics released in 2017 offer access to citing and citable articles, and it computes all published materials as citable articles ( Fernandez-Llimos, 2018). But, there was concern about citable items such as “notes”, “letter to the editor”, “editorials”, “erratum”, “retracted”, and there will be many unidentified items. This error has been fixed in the recently updated version of CiteScore metrics 2020, where they have fixed for the “articles”, “reviews”, “conference papers”, “book chapters” and “data papers” published. Scopus CiteScore has more excellent comprehensive coverage of published research data ( Fernandez-Llimos, 2018; Sau, 2020). Both JIF and CiteScore calculations are based on citations received by a journal in a given period for the published citable item in that duration ( Fernandez-Llimos, 2018; Sau, 2020). Significant and strong correlations were found between JIF and CiteScore in recent studies comparing 14-OT journals published in English ( T. Brown and Gutman, 2019). Hence, both JIF and CiteScore for measuring journal quality are used in our current study.

Thus, it indicates a requirement for a comprehensive bibliometric evaluation of OT literature using accurate and accessible matrices, which can be used to understand the global prospect of OT literature. These reasons prompted us to conduct a detailed bibliometric and scientometric analysis of research output in OT using the Scopus database. Hence, the following research questions were proposed. i)

What is the year-wise OT-publications trend in Scopus indexed journals for 2001-2020?

The overall OT publication trends revealed a steady growth of (7.72%) each year. In OT-specific and non-OT specific journals publication, growth was 0.29% and 7.44%, respectively ( Figure 1). Approximately one-fourth (24.30%) of articles were published in OT-specific journals in the last twenty years, and three-fourths (75.69 %) articles were published in non-OT-specific journals. From 2001 to 2020 the OT publications increased by 165.14 % (n = 1544). Similarly, the overall OT publication in OT-specific journals increased 14.84 % (n=57), whereas non-OT-specific journals overall publication increased 269.85% (n =1487).

A total of 16 OT-specific journals are listed in the Scopus database. Year-wise OT specific journal publication for the period of 2001 to 2020 showed in Figure 2. The top five journals published more than half of OT-specific journal publications. Those journals were American Journal of Occupational Therapy (AJOT) 18.42 %, British Journal of Occupational Therapy (BJOT) 17.56 %, Australian Occupational Therapy Journal (AOTJ) 11.53%, Canadian Journal of Occupational Therapy (CJOT) 7.64 % and Scandinavian Journal of Occupational Therapy (SJOT) 7.64 %, ( Table 1). Reaming articles were published in Occupational Therapy in Health Care (OTHC) 6.87 (n=511), Ergotherapie und Rehabilitation (ErgoR) 6.15 % (n=458), Occupational Therapy International (OTI) 5.28 %(n=393), OTJR Occupation, Participation and Health (OTJR) 4.27 % (n=318), Occupational Therapy in Mental Health (OTMH) 3.56% (n=265), Journal of Occupational Therapy, Schools, and Early Intervention (JOTSEI) 3.10 % (n=231), Physical and Occupational Therapy in Pediatrics (POTP) 2.42% (n=180), Physical and Occupational Therapy in Geriatrics (POTG) 2.24% (n = 167), Brazilian Journal of Occupational Therapy (BrJOT) 1.71 % (n=127), Hong Kong Journal of Occupational Therapy (HKJOT)1.32% (n =98), and Irish Journal of Occupational Therapy (IrJOT) 0.28 % (n=21).

The current analysis found that 14 out of the top-20 journals are OT-specific journals, which published one-fourth of OT articles from 2001 to 2020 ( Table 1). Among those journals, the AJOT received more citations (n = 27770), but the Archives of Physical Medicine and Rehabilitation (APMR) received the highest citation per document (37.27). CiteScore of those 20 journals ranges from minimum zero to a maximum of 5.7. Fifteen journals out of the top-20 journals have journal impact factors (JIF) or journal citation indicators (JCI). Six journals were indexed in the Emerging Sources Citation Index (ESCI) of WOS, whereas two journals were not listed in WOS. Impact factors for those 15 journals were rage from 0.03 to 3.966.

Among the top OT publishing countries, the US published the highest number of articles (n= 9517), followed by the UK, Australia, Canada, and Germany ( Table 2). The Netherlands received the highest citation per document (41.84), followed by Denmark, France, Italy, Norway. Furthermore, data revealed the US, UK, Australia, and Australia have solid international collaboration among the best 20 countries published in the past 20 years ( Figure 3).

The top five organisations publishing OT publications in the last 20-years are the department of occupational science and occupational therapy, the University of Toronto, Toronto, Canada, department of health sciences, Lund University, Lund, Sweden, school of rehabilitation science, McMaster University, Hamilton, Canada, school of health and rehabilitation sciences, the University of Queensland, Brisbane, Australia and department of occupational therapy, Colorado state university, Fort Collins, USA ( Table 3). Among the Top-20 university of British Columbia, Vancouver, Canada, received the highest citations (cpd = 200.50).

Among the top researcher, Brown T (n=128) was identified as a leading author with the maximum number of articles in the field of OT, followed by Eklund M (n=88), Kottorp A (n= 41), Rodger S (n=88), Ziviani J. (n=76) and Mackenzie I. (n=67). The top authors' citation per document and lifetime h Indexed are provided in Table 4. Further, the top-20 highly cited publications are listed in Table 5. The article published in 2017, received the 2309 citation was the highly cited article in the lancet. We observed a negative correlation (-0.14278) when comparing citations with the total year after publication.

Our study enlisted 20 author keywords commonly used in OT literature. Overall, the best 20 keywords were identified, with at least 50 occurrences in the OT publications ( Figure 4).

Over the last twenty years, overall OT publication output steadily increased, indicating the profession's growth in terms of research, and its dissemination is not significantly influencing the modern era of digitalization. Publication in non-OT-specific journals is three times more compared to OT-specific journals. A similar trend was also observed in recent studies ( T. Brown et al., 2019; Gutman et al., 2017; Folha et al., 2017; T. Brown, Ho et al., 2018; T. Brown, Gutman, and Ho 2018; Folha et al., 2019). This increase may reflect the growth of research activities in OT across the globe ( Folha et al., 2019). Occupational therapy works along with medical and other allied health professionals. It allows occupational therapies to work as a part of the multidisciplinary team. Similarly, it opens the door to interdisciplinary research opportunities. That multidisciplinary research is used to publish in either medical-related or multidisciplinary journals. Those journals have high JIF compared to OT journals ( T. Brown et al., 2019; Gutman et al., 2017; Folha et al., 2017; T. Brown, Ho et al., 2018; T. Brown, Gutman, and Ho 2018; Folha et al., 2019). A recent study found that non-OT-specific journals have three times more JIF than OT-specific journals ( Folha et al., 2019). These multidisciplinary and medical-oriented journals have more readers than OT-specific journals, giving more visibility and increasing the chance of receiving more citations. It may also encourage OT researchers to publish more in non-OT-specific journals ( T. Brown et al., 2019; Gutman et al., 2017; Folha et al., 2017; T. Brown, Ho et al., 2018; T. Brown, Gutman, and Ho 2018; Folha et al., 2019).

A total of five journals, such as AJOT, BJOT, AOTJ, SJOT, and CJOT, published half of the OT-specific journals articles. Previous studies also made similar observations ( T. Brown and Gutman 2019; T. Brown, Gutman, and Ho, 2018). These journals are well-known among the OT profession and have a long publishing history ( T. Brown and Gutman, 2019). AJOT, BJOT, AOTJ, and CJOT were published by prominent national organizations of OT and recognised by the global OT community ( T. Brown and Gutman, 2019). These journals' publication frequencies are more and published many articles per issue compared to other journals. Among these 16 OT journals, two journals, BrJOT and IrJOT, are new in the Scopus database and have data for the past three years. Hence, those journals will have a lower number of articles. According to the previous study, Scopus indexed OT-specific journal numbers was 14 ( T. Brown and Gutman, 2019). Among these two new journals, BrJOT published many articles in three years and placed under the best 20 journals that published OT-specific articles. OT-specific journals published one-third of total OT publications. Several OT-specific journals are published globally and have an online publication ( Cruz et al., 2019) but are not included in the Scopus database. Including all those OT-specific Journals might change the scenario of citation matrices of occupational therapy journals because occupational therapy journals tend to get more citations in for OT-specific journals.

Out of 20 top journals that produced the maximum articles in occupational therapy, the first eight are OT-specific journals. There is a normal phenomenon because these journals published OT-specific articles. ErgoR received more minor citations among those ten OT-specific journals due to its publication language. This is the only journal listed in the top twenty published in Germany. All other periodicals are published in the English language. AJOT, BJOT, AOTJ, SJOT, and CJOT received more citations in terms of overall citation. It may be due to their large volume of publications ( T. Brown and Gutman, 2019; T. Brown, Gutman, Ho, et al., 2018). AJOT, BJOT, AOTJ, SJOT, and CJOT received more than ten citations per document. Archives of Physical Medicine and Rehabilitation received more citations per document than any other journal listed in top-20, and it has the highest CiteScore and JIF. Among the OT-specific journals, POTP had the highest CiteScore (2.9), and AJOT had the highest JIF (2.246).

The US, Australia, UK, Canada, Germany, Sweden, Netherlands, and Italy are the top most country in terms of numbers of published articles, and this is different from that of the previous study ( T. Brown and Gutman 2019; T. Brown, Gutman, Ho, et al., 2018). The US published approximately one-third of total OT publications (n=9517). Other study findings also revealed that the US is the top OT article ( T. Brown, Gutman, Ho, et al., 2018). The US received many citations (216810) for the published documents. US is the country where OT originated from and also have a good education and research system in OT, which may be the reason for the huge number of the publication. The US is also the host country for a large number of OT-specific and non-OT-specific journals. This could also be a reason for the huge number of publications in occupational therapy. But citation per document is more minor for US articles than the Netherlands, Denmark, Italy, France, and Norway, with very few publications compared to the US. It may be due to the lack of availability of OT-specific journals in their geographic location, which triggered them to publish their research in non-OT specific journals with higher quality than OT-specific journals.

We found that the US, Australia, UK, and Canada are the leading countries in international collaborations in OT publications. The size of the level and circle indicate the weightage of collaborative activity. A bigger size represents more collaborations, and smaller size means fewer collaborations. The line between two nodes and their densities represents their link and strength ( Figure 3). Colour expressed different clusters levels based on international collaborations ( Van Eck and Waltman, 2019).

Among the top-20 organizations, 18 are either universities or entities of a university. This happens because universities are mainly placed in the urban set up with all necessary support such as research culture among academicians, well-equipped libraries with academic resources, affiliated hospitals, client participation, internal funding, grant office supports ( T. Brown et al., 2019). All this is favourable for more research output, which may cause university domination's top twenty organization list. Our study found only one organization in this top list: research institutes from Denmark and one occupational therapy association of USA. Though the US alone produced many OT articles, only five organizations are listed in the top 20, compared to US Canada (n=6) and Australia (n=5). Despite having a high volume of publications, less representation of US organization in the top list was also observed in previous studies ( T. Brown, Gutman, Ho, et al., 2018; Man et al., 2019). Other countries that are listed in top organizations are Denmark (n=1), Iran (n=12), Sweden (n=1), and Taiwan (n=1).

Australia (n=11) has the highest representation in the top author list, followed by Canada (n=1) Sweden (n=4), US (n =3), and Japan (n=1). The US authors are less in the top list instate having high publication volume. UK authors produce more publications after US authors, but there are no authors from the UK listed in the top 20 author list. Law M. from McMaster University, Hamilton, Canada had the highest h indexed (63) and Gitlin L. N from Johns Hopkins University, Baltimore, united states received the highest citation per document (57.51) among top-20 authors. Our study found Brown T as a top author in publication number. The finding of T. Brown, Gutman, Ho, et al. (2018) supported our study.

Out of the top-twenty highly cited articles for 2001 to 2020, four papers were published in 2008, two each in 2005, 2006, 2009, and 2012, one each in 2002, 2003, 2004, 2007, 2013, 2014, 2016, and 2017. Our study does not find any relation with year after with more citations. Our findings opposed previous studies' findings, which observe a long citation window helps an article gather maximum citation ( Gutman et al., 2017; T. Brown et al., 2019; T. Brown, Gutman, Ho, et al., 2018; T. Brown et al., 2017). Most of the highly cited papers are published in non-OT-specific journals. Most of the highly cited studies published non-OT-specific journals like earlier studies. Those non-OT journals are generally high-quality medical journals ( Gutman et al., 2017; T. Brown, Gutman, Ho, et al., 2018; T. Brown et al., 2019; T. Brown et al., 2017; T. Brown, Ho et al., 2018). It may happen due to the increased pressure to publish in journals with good impact factors or CiteScore. The quality of journals provides more visibility, which helps the author get more readership and citation because it helps in a grant application and promotion ( Gutman et al. 2017; T. Brown et al., 2019).

VOSviewer density visualisation ( Figure 4), by default, uses blue, green, and yellow to represent the density visualisation ( Van Eck and Waltman, 2019). The yellow colour indicates the number of items in the neighbourhood of a point and the higher weights of the neighbouring items. Out of the total best 20 keywords, “occupational therapy”, “rehabilitation,” and “stroke”, “physical therapy” and “activities of daily living” are five common keywords used more frequently in OT research, which are in yellow ( Figure 4). Occupational therapy and rehabilitation are commonly used as keywords because these two words are identical terms for the occupational therapy profession. The authors used these two words to make their research visible in the electronic search. Stoke is most probably the oldest and strongest research field, where occupational therapist works across the globe. Physical therapy is a common allied health profession occupational therapists may collaborate and publish together. Activities of daily living are one of the core practice areas of the occupational therapist.

This study retrieved scientometric information from the Scopus database and listed 25 journals along with their CiteScore and Journal Impact Factor. It was observed OT articles were published three times more in non-OT-specific journals, indicating that OT research is significantly overlapping with other disciplines of medicine. Hence, the investigation should not conclude a literature search with only OT-specific journals. The SJOT is one of the core OT journals but listed under subject category of “public health, environmental and occupational health” rather than the category of “occupational therapy”.