Abstract
This review highlights the opportunity to develop a stronger, evidence-based strategy for occupational therapy workforce development and professional advocacy.
The health workforce refers to all people engaged in actions whose primary aim is to enhance health (World Health Organization [WHO], 2006). It includes health professionals such as, but not limited to, nurses, pharmacists, physical therapists, physicians, and occupational therapists.
Occupational therapists are needed to meet the health, rehabilitation, and occupational needs of the population worldwide (World Federation of Occupational Therapists [WFOT], 2021). According to WFOT (2013), occupational therapists aim to improve the health and well-being of individuals and communities through the promotion of meaningful occupational engagement. Occupational therapists address the occupational needs of people experiencing a wide range of health conditions and disabilities, and they also assume health promotion roles (American Occupational Therapy Association, 2020). In addition, occupational therapists address health, human rights, and occupational injustices arising from socioenvironmental factors (Bailliard et al., 2020; Serrata Malfitano et al., 2016; WFOT, 2019).
To fulfill their societal role, occupational therapists need to be in sufficient supply, equitably distributed (e.g., across geographical or practice areas), and motivated in their everyday practice, and they need to meet key competency standards (WFOT, 2021). One strategy for assessing, meeting, or improving performance of these requirements is to develop and use occupational therapy workforce research. In particular, this research can identify current and future supply shortages; determine inequitable workforce distribution (e.g., scarcity in rural areas); and study the impact of policy, management, and regulations on workforce recruitment, retention, and performance (Campbell, 2013; Campbell et al., 2013; George et al., 2018; Kuhlmann et al., 2018). Overall, health workforce research is key to providing evidence to inform and evaluate population-centered workforce policies and practices, as well as development and professional advocacy activities (Buchan et al., 2020; George et al., 2018; Kuhlmann et al., 2018).
The World Health Organization’s (WHO’s; 2016b) Global Strategy on Human Resources for Health provides global guidance for health workforce research and development as a whole. At the health professions level, the WHO (2016a ; Ajuebor et al., 2019) also launched the Global Strategic Directions for Strengthening Nursing and Midwifery, a profession-specific framework used to guide global, concerted developments for this workforce.
With respect to the rehabilitation field, strategies to guide workforce development have been reported (Gimigliano & Negrini, 2017; Jesus et al., 2017), and WHO recently launched the Rehabilitation Competency Framework to provide a cross-professional, cross-national tool for framing, studying, and developing the competencies of the rehabilitation workforce (Mills et al., 2021).
Finally, WFOT (2021) recently published a position statement endorsing the role and value of workforce research and development activities for the occupational therapy profession, including identifying and reducing workforce disparities to improve access to occupational therapy. Little is known, however, about occupational therapy workforce research, warranting the need to map workforce research at the global level.
The aim of this scoping review was to identify and map the extent, range, and nature (e.g., volume, topics, geographical focus, funding status, study design, and methods) of occupational therapy workforce research worldwide. An assessment of the global status of such research can help inform strategic directions for further investigations in this area.
Method
Design
Scoping reviews often address exploratory research questions with the aim of mapping concepts, research methods, and types of evidence; they also identify gaps in the literature or in a research area. In short, scoping reviews determine the volume and nature of research activity on a broad topic to inform policy, practice, and research (Colquhoun et al., 2014; Levac et al., 2010; Peters et al., 2021; Tricco et al., 2018).
In addition to the traditional Arksey and O’Malley (2005) framework and subsequent refinements (Colquhoun et al., 2014; Daudt et al., 2013; Levac et al., 2010), we followed the recent Joanna Briggs Institute’s guidance for the conduct of scoping reviews (Peters et al., 2020). Although the review protocol is not registered (the PROSPERO database does not accept scoping review protocols), it has been peer reviewed and published a priori (Jesus et al., 2021). The protocol provides a detailed description of the review procedures and methodological options; here, we provide a synthesis of the methodology we used.
In this article, we provide the first part of our scoping review results: a quantitative map of the volume, yearly distribution, topics, geographical focus, study design and methods, and funding status of the included literature. The types of findings and reported recommendations or limitations—largely a qualitative synthesis—will be published in a separate article.
Database Searches
Systematic searches of six electronic databases (MEDLINE/PubMed, Web of Science Core Collection, Scopus, CINAHL, PDQ–Evidence for Informed Health Policymaking, OTseeker) were conducted in June 2021. The full details of the search strategy for the MEDLINE/PubMed database, which was used to guide the searches of the other databases, can be found in Jesus et al. (2021). The search strategy was built by Tiago S. Jesus, who has an extensive track record in bibliometric research and in designing database search strategies for the rehabilitation and health workforce fields, and it was appraised with the Peer Review of Electronic Search Strategies guidelines (McGowan et al., 2016). Web of Science and Scopus cover multidisciplinary literature beyond the health sector, which accommodates the diverse practice fields (e.g., educational and social sectors) in which occupational therapists work, in addition to the health sector.
The gray literature, here only official research-based reports, was searched through screening and keyword searches of the websites of the following select international institutions: WFOT, the rehabilitation and health workforce subsections of WHO, the Health Workforce Research section of the European Public Health Association, and the member organizations of WFOT, as planned in the protocol (Jesus et al., 2021).
Finally, we also used snowballing techniques (e.g., searching reference lists of included articles, author tracking), and we consulted with representatives of 105 WFOT member organizations. We supplied them with a preliminary list of inclusion criteria and asked them to identify any additional references that potentially fit the criteria and were missed from the combination of search strategies. Sixteen member-organization representatives responded and collectively generated 15 additional articles considered for inclusion.
Eligibility Criteria
We included occupational therapy workforce research fitting at least one category of workforce research defined a priori in the study protocol (Jesus et al., 2021). Table 1 describes each inclusion category as synthesized from the protocol. The design of the inclusion categories was informed by a WFOT (2021) position statement; a review of the rehabilitation workforce literature (Jesus et al., 2017); the Global Strategy on Human Resources for Health (WHO, 2016b); and a reader on health policy, systems, and services research falling into the spectrum of health workforce research (George et al., 2018).
Inclusion Categories for the Major Workforce Research Topics Included in the Scoping Review, Synthesized From the Review Protocol (Jesus et al., 2021)
Although Table 1 includes workforce production topics (e.g., number of new graduates entering the profession), studies on the education of occupational therapists from a curriculum or pedagogical perspective were excluded. Students contribute to workforce development, but educational research is a gigantic field and a subject on its own; this scoping review focuses on the workforce of those in practice, ready to practice, or in transition from or to practice. Similarly, studies of occupational health (e.g., prevalence of burnout) were excluded, unless they involved explicit human resources practices such as recruitment, retention, or productivity. Revisions of or updates to scope of practice or competency standards were also excluded, unless their development or evaluation is framed as a study (e.g., with a given, replicable methodology).
Methodologically, we included any quantitative, qualitative, or mixed-methods research, including secondary analyses, case studies, and systematic or scoping reviews, as long as it was published in a peer-reviewed journal or an official institutional venue (e.g., governmental or nongovernmental agencies) at the global, regional, national, or provincial or state level. We planned to review articles available in English, Spanish, and Portuguese. To avoid language restrictions, we also planned to obtain translated versions of documents published in other languages, when available (Jesus et al., 2021), although no such articles emerged in the review process. We excluded editorials, letters, conference abstracts, posters, study protocols, peer-reviewed articles without an abstract, perspective papers, narrative reviews, and broad raw databases or papers that did not address a study question, have replicable methods, or include analysis, interpretation, or implications of the results.
Articles on the occupational therapy workforce or with occupational therapists as participants were included, even if they included other professions or workers—including associate professionals, such as occupational therapy assistants. To be included, however, articles needed to report either comparative or stratified results for occupational therapists. Articles were excluded when the data or results were fully aggregated with those of other health workers.
Using these criteria, two independent reviewers (Jesus and Karthik Mani) conducted title and abstract screening and full-text review to determine eligibility. This process was conducted after the two reviewers reached 80% or greater agreement in pilot tests on at least 5% of the references. For the full-text screening, one or two rounds of discussions were needed for the reviewers to reach consensus on papers rated differently on eligibility. Although we planned to consult a third reviewer to resolve disputes, there was no need to do so.
As defined in the protocol, we reviewed the literature from all geographical areas with no time limitation, but we could have applied a temporal cutoff a posteriori as collectively determined by the authors in the face of saturation (Jesus et al., 2021). We did not apply the temporal cutoff to the eligibility determination, but data extraction was subsequently conducted only for articles published since 1996. In the face of more recent publications, we determined that there was no benefit to extracting and analyzing data from articles published more than 25 yr ago.
Data Extraction
Citation elements such as journal titles and dates were extracted from the reference management software (EndNote). We extracted data relating to methodology or study design, participants (number and type), data sources, data types, study aim or research questions, use of standardized instruments, and use of inferential statistics. Also, we extracted the geographical areas addressed (type and specific location) and the existence of funding support. We conducted a pilot test of the data extraction process with two independent reviewers (Jesus and Mani) for 10% of the included references. Then, one experienced reviewer (Jesus) extracted the information, which was then fully verified by another research author (Mani, Sutanuka Bhattacharjya, or Sureshkumar Kamalakannan). As is typical in scoping reviews (Colquhoun et al., 2020; Peters et al., 2015), quality appraisals were not performed.
Data Synthesis
The findings incorporate a summative description of the extent and range of the literature for the extracted information. For each type of information, we used descriptive statistics, such as percentage of the included studies with a given characteristic (e.g., those who focused on a given country) or grouped characteristics (e.g., those focused on low- and middle-income countries [LMICs]). We also used inclusion categories (see Table 1) to provide the structure to report on the number and percentage of papers per large topic type. To determine the growth trend of publications over the years, we used a simple linear regression analysis with years as the independent variable and number of publications as the dependent variable. The analysis was conducted in Excel, with an add-in for statistical analysis (XLMiner Analysis ToolPak) to compute the simple linear regression. Finally, for the free-text quotations extracted on the aims of each study (i.e., qualitative data), we developed a summative content analysis approach (Hsieh & Shannon, 2005) to determine more specific topics addressed by the included studies.
Results
Figure 1 shows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart for this scoping review. Of 1,246 deduplicated articles initially assessed for eligibility, 141 were subject to full-text review, and 78 met the inclusion criteria. Of these, 57 articles were published after the temporal cutoff (i.e., they had been published since 1996). We extracted and analyzed data from these publications.
Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart for the selection of studies for the scoping review.
Figure 2 provides the distribution of articles for the primary category alone and for both primary and secondary categories combined. The categories of “attractiveness and retention” and “workforce distribution” were those most frequently addressed as a primary or secondary topic, at 27% and 16% of the occurrences, respectively.
Distribution of articles in each inclusion category.
Table A.1 in the Supplemental Appendix (available online with this article at https://research.aota.org/ajot) provides the key data extracted from each article by primary inclusion category. A total of 28 papers (49%) met more than one inclusion category.
The scope of the literature is summarized next, using various categories of analysis.
Annual Volume and Growth
An analysis of the annual volume and growth of occupational therapy workforce research indicated an erratic evolving trend (r 2 = .26), with no more than 7 articles published worldwide in a single year and, in some recent years (2011, 2012, 2016, 2017), fewer than two publications per year. Although we found a statistically significant growth trend for the total number of articles published each year (p < .01), the slope of the linear regression model (b = 0.07) indicates that it will take 14 yr to increase the annual publication rate by one additional article.
Study Design
Cross-sectional surveys accounted for most of the publications (n = 30; 53%), and secondary analyses (n = 10), qualitative research (n = 5), and systematic reviews (n = 4) accounted for 18%, 9%, and 7% of the included articles, respectively. Three studies had unique study designs, which included 1 pilot experiment study (Rodger, Thomas, et al., 2009).
Participants
A total of 5,813 occupational therapy participants were directly involved in the primary research (i.e., excluding systematic reviews and secondary analyses of databases). Among the articles included, 75% (n = 43) focused only on occupational therapists, whereas 25% (n = 14) included data from occupational therapists compared with or disaggregated from other types of health workers.
Geographical Areas
A total of 9% (n = 5) of the articles had a transnational or worldwide focus. Most focused on specific countries, either the country overall (58%; n = 33) or a region, province, or state (18%; n = 10); rural or remote area (9%; n = 5); or metropolitan area of a given country (7%; n = 4). Among the articles focused on specific countries (n = 52), Australia accounted for 31% (n = 16), followed by the United States (30%; n =15), Canada (12%; n = 5), and the United Kingdom (6%; n = 3). Four articles addressed LMICs: two for Brazil and 1 each for India and South Africa, for a total of 7% of included articles. One additional article (2%) addressed the anglophone sub-Saharan Africa as a resource-poor global region.
Publication Venue
All of the articles except 1 were published in peer-reviewed journals. Aligned with the geographical focus, the Australian Occupational Therapy Journal was the publication venue for 24% (n = 13) of the peer-reviewed publications; the American Journal of Occupational Therapy published the second highest number of peer-reviewed articles (9%; n = 5). In total, most peer-reviewed articles (57%) were published in occupational therapy journals. Among the articles published in non–occupational therapy journals, the most common choice for publication was Human Resources for Health (6%; n = 3).
Sources of Data or Participants
The sources of data or methods for recruiting participants were diverse. For example, 19% (n = 11) of the included articles used data sourced from licensing or registration bodies, and 12% (n = 7) used data from national associations. A greater percentage of articles (25%; n = 14) used more than two sources to obtain data or recruit participants.
Study Question Type, Data Collection Tools, and Data Analysis
A total of 77% (n = 44) of articles focused on either descriptive or exploratory research questions, and 23% percent (n = 13) addressed an analytical type of question (e.g., determining statistical associations, predicting supply–demand shortages, examining the impact of a new policy or intervention); 2% (n = 1) explicitly tested a hypothesis.
Aligned with these findings, 10% of the eligible articles (i.e., excluding qualitative research and systematic reviews) used standardized tools; 39% of articles with quantitative data applied inferential statistics during the analysis.
Funding Status
A total of 70% of papers (n = 40) reported no form of funding support. Altogether, 21% of articles (n = 12) reported external funding. Four percent (n = 2) used intramural funding, and 5% (n = 3) reported funding support for specific authors (i.e., not for the specific research project or program).
Of the 17 articles reporting funding, one was a cross-sectional survey study with an exploratory study question (6%), in contrast to the articles without funding (n = 40), which relied heavily on cross-sectional survey studies and exploratory study questions (53%; n = 21). Sixty-five percent of the funded articles used inferential statistics compared with 20% of the unfunded articles (i.e., 8 of 40).
A total of 47% of the articles reporting funding (i.e., 8 of 17) focused on data for both occupational therapists and other workers. In turn, 88% of the 40 nonfunded articles (n = 35) used data for occupational therapists only and thereby were less able to establish cross-professional comparisons.
Content Analysis of Specific Topics
A qualitative analysis of the study aims of the articles included in this scoping review identified common topics for occupational therapy workforce research.
Seven articles addressed workforce attractiveness and retention in mental health (Ceramidas et al., 2009; Hunter & Nicol, 2002; Rodger, Thomas, et al., 2009; Scanlan et al., 2013; Scanlan & Still, 2013; Scanlan & Still, 2019; Scanlan et al., 2010), including 4 articles that had the same first author. In turn, 5 Australian articles addressed the issues of attractiveness and retention specifically in rural or remote areas (McAuliffe & Barnett, 2009, 2010; Merritt et al., 2013; Mills & Millsteed, 2002; Millsteed, 2000).
Among other topics addressed by workforce studies, 4 articles focused on continuing professional development behaviors and licensing requirements (Fields et al., 2021; Hall et al., 2016; Vachon et al., 2018; White, 2005); 4 studies from the United States determined that there were workforce shortages or surplus based on supply and demand data (HRSA Health Workforce, 2016; Lin et al., 2015; Powell et al., 2005, 2008), and 3 focused on variation in employment and staffing levels in skilled nursing facilities in the context of reimbursement policy changes in the United States (McGarry et al., 2021; Mroz et al., 2021; Prusynski et al., 2021).
Finally, 3 articles focused on internationally trained occupational therapists, including 2 from Canada that investigated workforce integration (Dhillon et al., 2019; Mulholland et al., 2013; Pittman et al., 2014). No other topics were addressed by more than 2 articles.
Discussion
This scoping review highlights the global status of occupational therapy workforce research worldwide. Our results show a limited volume of such research, with weak growth over time, little focus on LMICs, a restricted breadth of topics, an overreliance on exploratory cross-sectional surveys, the limited use of inferential statistics, a lack of experimental studies, and low rates of funding support. Furthermore, the review indicates that the studies with funding support tended to use stronger methodology. All of these findings are worthy of discussion.
The findings revealed a low volume of occupational therapy workforce research, coupled with weak annual growth (i.e., 14 yr to add one additional yearly publication; 2011 and 2012 without a single publication), especially when compared with other health workforce research. As many as 867 research articles were found for health workforce research topics in 2018 alone, with a significant and exponential type of growth over time from 129 yearly publications in 1990 to nearly 900 in 2018 alone (Jesus, Castellini, et al., 2022). In volume and growth, occupational therapy workforce research production lags behind expectations.
A few examples of commonly researched topics were found, including career attractiveness and retention issues (e.g., mental health as a practice area, practicing in rural areas) with studies in this area coming predominantly from Australia. Determining supply–demand shortages and the impact of changed reimbursement policies on reduced staffing and employment levels were study topics that came exclusively from the United States. In turn, Canada was the country with primary research articles studying internationally trained occupational therapists.
It is possible that country-specific policies, culture, or the overall landscape of research and its funding have shaped these country-specific patterns of occupational therapy workforce research. For example, studies and research structures for studying or forecasting workforce shortages for varied health professions are common in the United States (Juraschek et al., 2019; Landry et al., 2016; Ricketts et al., 2021; Zhang et al., 2018, 2020; Zimbelman et al., 2010). Similarly, supplying rural and remote areas of the country with a needed and capable health workforce is a major policy, research, and research policy priority in Australia (Gillam et al., 2021; Russell et al., 2021; Wakerman et al., 2019). Finally, the Canadian studies on internationally educated occupational therapists were funded with sponsorship of governmental bodies in two provinces focused on employment and immigration issues (Dhillon et al., 2019; Mulholland et al., 2013).
Overall, the trends identified in this scoping review may be derived more from country-specific policies, research, or funding priorities than from any particularly needed occupational therapy–specific workforce topics prevalent across nations. Unlike for other health professions, such as nursing (WHO, 2016a), no global guidance exists for the development of occupational therapy human resources and workforce research. As a result of these findings, the WFOT aims to use a research- and consultation-based process to develop a strategy to provide such guidance.
The rates for funding of workforce research found in this review were not remarkable. Only 30% of included articles reported any form of funding (25%, if funding that supported only individual authors is excluded). These values differ from funding levels usually identified for health workforce research. Since 2010, the percentage of health workforce research with funding support has been stable at approximately 50% (Jesus, Castellini, et al., 2022), with rehabilitation- related health policy, systems, and services research receiving funding support at a level of 55% (Jesus et al., 2020). These findings help explain, in part, a suboptimal application of more advanced or stronger research designs and methods in the occupational therapy workforce literature. Funding occupational therapy workforce research at more standard rates will likely improve both the quantity and the quality of the methods used in occupational therapy workforce research and thereby provide a stronger evidence base for professional advocacy and workforce developments.
Of the 57 included articles, 7% focused on LMICs, which contrasts with the 77% of the world’s rehabilitation needs coming from LMICs (Jesus et al., 2019). Although this is a common problem in other areas of health research (i.e., LMICs account for about 12% of rehabilitation-related health policy, systems, and services research; Jesus et al., 2020), the low volume of research on LMICs may raise global public health concerns.
Existing data indicate scant, limited, or nonexistent occupational therapy workforces or education programs in many LMICs (Agho & John, 2017; Ledgerd & WFOT, 2020). Models of service delivery and workforce supply to feasibly meet the health and occupational needs of their populations might differ in many LMICs. Hence, there is a strong need to develop and study efficient and feasible means to develop the workforce in these contexts. This review, however, shows that occupational therapy workforce research rarely tackles issues in LMIC contexts.
We found that only 9% of the included articles had a cross-country focus, which prevents cross-national comparisons, benchmarks, partnerships, or knowledge exchange on the so-called North–North (Jesus, Landry, et al., 2022), South–South (Were et al., 2019), and North–South (Mwangi et al., 2017) partnerships on workforce research and developments (here North equates to high-income nations and South to LMICs).
Greater cross-national partnerships for occupational therapy workforce research have the potential to address existing issues with the lack of data on the international mobility of occupational therapists. Also, we found no studies directly looking at the international recruitment of occupational therapists or on the ethical issues that may arise from such recruitment (WFOT, 2014).
Limitations of this scoping review include the lack of inclusion of research on the education of occupational therapists, despite the key importance of education for the development of the profession. We included workforce research (i.e., with a study question and reported methodology) but not other forms of reports or databases with workforce data. This choice reflects a focus on knowledge generation beyond data generation. We did not search the ProQuest Dissertations and Theses Global database because our focus was on studies published in the peer-reviewed literature or in institutional venues such as governmental or nongovernmental agencies. Although we did not have language restrictions on eligibility and used diverse search strategies (including key informants from diverse countries), we were unable to map literature in languages other than English. As a result, underrepresentation of literature from geographical areas using languages other than English in reporting research cannot be ruled out. Finally, we did not focus on reporting the findings, recommendations, and limitations that are a subject for other reports on this study (Jesus, Mani, Ledgerd, et al., 2022; Jesus, Mani, von Zweck, et al., 2022).
Implications for Occupational Therapy Practice
This scoping review uncovered the global status of occupational therapy workforce research worldwide and highlights the need for it to be strengthened. It has the following implications for occupational therapy practices: ▪ Occupational therapy stakeholders such as those in practice, academia, research funding, and policy and professional advocacy roles may collaborate (at the global, country, and regional levels) to develop systemic, strategic, and methodologically stronger occupational therapy workforce research agendas. These agendas may provide a more solid body of research and evidence to identify and address workforce gaps and thereby promote equitable population access to competent occupational therapy services. ▪ Funders of occupational therapy research or of health policy, systems, and services research may support funding (e.g., earmark a percentage of funds) for occupational therapy workforce research to align with funding of other health human resources research. This advancement is likely to strengthen the quantity, methods, and value of occupational therapy workforce research and evidence to inform everyday professional advocacy and workforce development practices.
Conclusion
Occupational therapy workforce research is key in providing evidence regarding whether and how the occupational therapy workforce exists in sufficient quantity, is equitably distributed, and meets key competency standards. The results of this scoping review map the global status of occupational therapy workforce research, which was found to be scant, barely growing, and inequitably distributed by geographical area; to use suboptimal methods; and to be underfunded, with stronger methods for the studies that were funded.
Apart from a few examples of research topics, mostly country specific, we could not find long-term research programs or agendas for the systematic study of the occupational therapy workforce. Doing so may be necessary to generate an evidence base for guiding and assessing occupational therapy workforce policies, advocacy, and development practices.
According to gaps identified in this review, concerted stakeholder development is required to strengthen funding mechanisms, provide guidance on topics and research questions to be addressed, and enhance the methodology of the occupational therapy workforce research within and across nations.
To align with strategic directions for health human resources (WHO, 2016b) and for specific health professions such as the nursing workforce (WHO, 2016a), there is a need to develop a global strategy and research agenda to strengthen the status of occupational therapy workforce research. The WFOT is planning to develop such a strategic guidance at the global level.
Supplemental Material
Supplementary material for The Global Status of Occupational Therapy Workforce Research Worldwide: A Scoping Review
Supplementary material, sj-pdf-1-aot-10.5014_ajot.2023.050089.pdf for The Global Status of Occupational Therapy Workforce Research Worldwide: A Scoping Review by Tiago S. Jesus, Karthik Mani, Claudia von Zweck, Sutanuka Bhattacharjya, Sureshkumar Kamalakannan and Ritchard Ledgerd in The American Journal of Occupational Therapy
Footnotes
*
Indicates articles included in the scoping review.
Acknowledgments
We thank the WFOT delegates and other member organization representatives who suggested papers for inclusion in this scoping review. Tiago S. Jesus completed this work under a grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR; 90ARHF0003). NIDILRR is a center within the Administration for Community Living (ACL), U.S. Department of Health and Human Services (HHS). The contents of this publication do not necessarily represent the policy of NIDILRR, ACL, or HHS, and the reader should not assume endorsement by the U.S. federal government.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
