Flexible global working arrangements: An integrative review and future research agenda

The topography of global mobility within multinational enterprises (MNEs) is evolving where we now have a portfolio of flexible global working arrangements (FGWAs) including: international business travellers, flexpatriates, short-term international assignees, international commuters, and rotational assignees. The need for more agile structures and more efficient mechanisms to transfer globally dispersed knowledge are two key enablers in this evolution. With increased interest, this paper offers the first systematic, integrative review of 100 articles on FGWAs. The review indicates that these forms of global work appear to be a somewhat overlooked double-edged sword in that they may confer significant but unrealised value for MNEs alongside hidden, adverse consequences for individuals. Notable was the lack of insight into the HR function's input or oversight at either a strategic or operational level. We find that there is a distinct lack of strategic linkages to global mobility and/or HR functions. We propose a research agenda that centres on better understanding the international HR function's role and responsibility in providing a more strategic and sustainable perspective of these increasingly common FGWAs alongside virtual work. The COVID-19 pandemic may offer a critical juncture point in which there is greater strategic consideration on the utilisation and support of such arrangements.


Keywords:
Global mobility Flexible global work International assignments Global strategy Value creation Boundary spanning IHRM

A B S T R A C T
The topography of global mobility within multinational enterprises (MNEs) is evolving where we now have a portfolio of flexible global working arrangements (FGWAs) including: international business travellers, flexpatriates, short-term international assignees, international commuters, and rotational assignees. The need for more agile structures and more efficient mechanisms to transfer globally dispersed knowledge are two key enablers in this evolution. With increased interest, this paper offers the first systematic, integrative review of 100 articles on FGWAs. The review indicates that these forms of global work appear to be a somewhat overlooked doubleedged sword in that they may confer significant but unrealised value for MNEs alongside hidden, adverse consequences for individuals. Notable was the lack of insight into the HR function's input or oversight at either a strategic or operational level. We find that there is a distinct lack of strategic linkages to global mobility and/or HR functions. We propose a research agenda that centres on better understanding the international HR function's role and responsibility in providing a more strategic and sustainable perspective of these increasingly common FGWAs alongside virtual work. The COVID-19 pandemic may offer a critical juncture point in which there is greater strategic consideration on the utilisation and support of such arrangements.

Introduction
In order for multinational enterprises (MNEs) to adapt to increasing volatility, complexity, and uncertainty in the global environment, there is an urgent need to develop and leverage more innovative and flexible forms of global mobility (Collings & Isichei, 2018;Reiche, Lee, & Allen, 2019). The acceleration of globalisation in recent decades, coupled with demographic, geopolitical, economic, and information technology (IT) changes and the increased ease of international travel, has seen continued use of expatriate assignments (Miralles-Vazquez & McGaughey, 2015) alongside the rise of other forms which we termflexible global working arrangements (FGWAs) (Cascio & Aguinis, 2008;Collings, Scullion, & Morley, 2007;Shaffer, Kraimer, Chen, & Bolino, 2012). The rise of FGWAs is paralleled by MNEs pursuing more agile structures and a desire to enable knowledge transfer in more efficient and effective ways (Meyer, Li, & Schotter, 2020). Despite a rise of populism and protectionism in recent years, MNEs continue to expand following a strategy of international diversification (Hitt, Li, & Xu, 2016) while seeking to maintain a balance between global integration and local responsiveness (Verbeke & Kano, 2016). In this context, globally mobile workers traversing borders and continuously engaging in faceto-face exchanges act as highly valuable boundary spanners between headquarters (HQ) and foreign subsidiaries (Barner-Rasmussen,

International human resource management: Moving beyond expatriation in global mobility
The IHRM literature is heavily centred on what can be viewed as more conventional or traditional forms of global mobility which encompass the relocation of an employee, and possibly their family, for more than one year (Tahvanainen, Welch, & Worm, 2005). With a talent gap cited across many Western economies and the growing importance of emerging markets, a significant macro-level shift of mobility patterns has commenced on a global scale (Deloitte, 2019;PwC, 2010). We now briefly describe the FGWAs of interest in this review paper.
IBTs are typically described as those 'for whom business travel is an essential component of their work' (Welch & Worm, 2006, p.284 cited in Collings et al., 2007) that usually involves travelling for a few days and up to three weeks (e.g. Druckman, Harber, Liu, & Quigley, 2014;Puchmüller & Fischlmayr, 2017;Shaffer et al., 2012). As such, they do not relocate on any sort of medium-to short-term basis. IBTs are based in a home country and maintain close connections with the home country while being on a business trip (Westman, Etzion, & Gattenio, 2008). A term used synonymously is international frequent flyers (Minbaeva & Michailova, 2004) and multiple trips to various locations are common (Shaffer et al., 2012). Flexpatriates refer to employees 'who travel for brief assignments, away from their home base and across cultural or national borders, leaving their family and personal life behind' (Mayerhofer, Hartmann, Michelitsch-Riedl, & Kollinger, 2004b, p.1371. This typically involves being assigned to a host country for one to two months (Shaffer et al., 2012). International commuters are best defined as employees who commute 'from a home country to a place of work in another country, usually on a weekly or bi-weekly basis, while the family remains at home' (Mayerhofer et al., 2004b(Mayerhofer et al., , p.1375. The employee returns home at frequent intervals, travels during the week, spends weekends in the home country, and is assigned to a particular host country which usually does not change (Mäkelä et al., 2017;Suutari, Brewster, Riusala, & Syrjäkari, 2013). Rotational assignees operate internationally on a shift cycle (Baker & Ciuk, 2015;Shortland, 2018) and thus commute from their home in one country to their workplace in another country for a short period which is then followed by a period of time off back home (Collings et al., 2007, p.206). This is a common approach used in hardship and offshore locations (Ross, 2009) with the mining, oil, and gas industries being key examples of this arrangement (Mayerhofer et al., 2004b;Shortland, 2018). Finally, STIAs are employees who undertake an international assignment that is longer than business travel but shorter than traditional expatriation (Tahvanainen et al., 2005). There is no agreement on duration with Collings et al. (2007) indicating one to twelve months while Shaffer et al. (2012) speak to a duration of three to twelve months to further differentiate it from flexpatriation (one to two months).

Systematic review methodology and analysis
To identify relevant publications for the purpose of this integrative review, we utilised three of the most highly regarded databases that provide an adequate coverage and a capability to perform systematic searches (Gusenbauer & Haddaway, 2020): Web of Science   Anderson (2007) To examine whether wages are higher in those developing countries to which business travel and telecommunication is cheaper and easier IBTs -Empirical: quantitative, analysis of economic data The amount of business travel received by developing countries is significantly correlated with various proxies for travel and communication costs; the amount of inward business travel has a positive effect on per capita GDP Andresen and Bergdolt (2019) To examine individual and job-related antecedents of a global mindset in the context of IBTs IBTs Constructivist theory (Honebein, Duffy, & Fishman, 1993) Empirical: quantitative, 624 surveys Individuals' personality traits, motivation, and jobrelated factors are positively related to the IBTs' level of global mindset; business travel needs to provide developmental challenges if it is to promote learning processes Atkinson and Pareit (2019) To explore the nature of psychological contracts of IBTs IBTs Psychological contract (Herriot, Manning, & Kidd, 1997) Empirical: qualitative, 9 interviews, manufacturing and consulting sectors IBTs' psychological contract is more relational in nature than might be expected with a mix of relational and transactional obligations; effective management is essential to realising IBTs' full strategic value Baker and Ciuk (2015) To explore the work-family interface of IBTs and rotational assignees IBTs, rotational assignees -Empirical: qualitative, 20 interviews, 1 MNE from the UK, engineering sector Four key factors affect the work-family interface: time spent away, unpredictability of schedules, limited control, and limited organisational support Barish and Dilchert (2010) To examine the responsibilities of HR when managing IBTs in relation to radiation exposure IBTs -Conceptual IBTs who often travel on high-altitude transcontinental or international flights receive a high radiation exposure; HR must recognise this potential health risk and provide education and dose assessment Bathelt and Henn (2014) To develop a typology of geographies of knowledge transfer over distance IBTs -Conceptual Three configurations of knowledge transfer build upon temporary face-to-face interaction: international community gatherings, international business travel, and transnational network relations Beaverstock et al. (2009) To review the function, modes, and spaces of business travel and its impact on IBTs and the environment IBTs -Conceptual International business travel allows firms to manage their global structures, liaise with external suppliers and contractors, and service its obligations to clients; technology has not led to the reduction in travel anticipated Belenkiy and Riker (2012) To investigate the contribution of international business travel to US exports To explore the context of conventional assignments and alternative forms of international assignments IBTs/frequent flyers, international commuters, rotational assignees, STIAs, virtuals -

Conceptual
Points to the emergence of a portfolio of alternatives to the traditional international assignment; HR issues and implications are explored; a standardised approach to managing these assignments is untenable Collins and Tisdell (2004) To explore the relationship between Australian business returns and international business travel IBTs Managerial theory of the firm ( Williamson, 1963), model of sales maximisation ( Baumol, 1959) Empirical: quantitative, analysis of economic data      (Minuchin, 1974) alumni from 1 university from the USA impact on willingness to travel or to take on assignments; career fit is related to higher willingness to accept travel or assignments  To understand spouses' willingness to relocate and managers' willingness to take on a global assignment STIAs, traditional expatriates Family systems theory (Minuchin, 1974) Empirical: quantitative, 594 surveys, global managers, alumni from 1 university from the USA Spouse willingness to relocate exerts a positive influence on managers' willingness to take on an assignment; job involvement is the most significant negative predictor of spouses' willingness to relocate Liese et al. (1997) To investigate whether IBTs experience disease due to work travel To examine the effects of the job demands and resources on psychological well-being IBTs JD-R model ( Demerouti et al., 2001) Empirical: quantitative, 232 surveys, 3 MNEs and 1 trade union from Finland, energy sector The high workload and pressure arising from international business travel relate directly to job exhaustion, which, in turn, is likely to lead to health problems and lower job performance; supportive HR practices are linked to satisfaction Mäkelä, Bergbom, et al. (2015) To examine the effect of gender and parental status on the relationship between travelling days and work-tofamily conflict IBTs COR theory ( Hobfoll, 2001) Empirical: quantitative, 1366 surveys, 4 MNEs, and 1 global public firm An increase in the number of travelling days and being a parent leads to increased work-life conflict; policies need to consider the family status of travellers Mäkelä et al.
To examine the effect of an international career orientation on the relationship between IBTs ERI model (Siegrist, 1996) Empirical: quantitative, 232 surveys, 3 MNEs and 1 trade union from Finland, energy sector The balance between efforts and reward affects both enrichment and conflict experiences; a career (continued on next page)    (House & Kahn, 1985) Empirical: qualitative, 51 interviews Women mainly value and use emotional and instrumental support which is mainly derived from within family; informational support is less relevant Ramsey (2013) To understand perceived strains that affect IBTs IBTs Institutional theory (Scott, 2001) Empirical: quantitative, 551 surveys Institutional distance leads to both travel and job strain; pre-assignment training and development programmes should aim to reduce institutional distance Ramsey et al.
To examine the influence of cultural intelligence on dealing with strain caused by institutional distance

IBTs
Institutional theory (Scott, 2001) Empirical: quantitative, 841 surveys Cultural intelligence development helps to lower individual strain in business travel; this is especially important regarding the reduction of travel strain caused by perceived normative differences Rezaei et al. (2018) To examine the relationship between risk perceptions and business travel   Core Collection, Scopus, and EBSCOhost Business Source Complete. The objective was to identify all conceptual and empirical articles on FGWAs. For the initial search, we set three inclusion criteria: (1) peer-reviewed journal articles, (2) written in English language, and (3) at least one of the following search term(s) needed to be in either the title, abstract, or keywords: international business travel/ traveler/traveller; frequent flyer; international frequent flyer; flexpatriation; flexpatriate; international commuter; rotational assignment/assignee; and short-term international assignment/assignee. We did not enter a starting date to allow us to establish when the first paper was published while our end date was the time of the search which was March 2020. Conference papers, editorials, books, and book chapters were not considered as a peer-review process could not be guaranteed. Our systematic database search process is illustrated in Fig. 1.
A total of 4740 records were identified through the database searching. We then proceeded to exclude records based on screening of the titles and abstracts. We excluded papers that did not address FGWAs. For example, papers that referred to rotational assignments (motion of particles) in the fields of physics and chemistry were excluded. Similarly, papers that referred to frequent flyers but only focused on airline frequent flyer schemes were disregarded; papers that focused on leisure travel as opposed to business travel were also excluded. This resulted in 258 records after the initial screening. We then excluded records based on duplicity, i.e. articles appearing in either both databases or across search terms which led us to arriving at 122 unique articles. At this juncture we assessed the records for eligibility based on the full paper, i.e. we read each paper in detail to determine relevance. This led to the exclusion of an additional 22 papers. Those excluded at this stage tended to be because while there may have been mention of one or more of the FGWAs, it was so peripheral to the paper it offered nothing by way of knowledge advancement. Papers that focused on traditional expatriation or did not consider an international context were also excluded. Consequently, the final sample for our review were 100 peer-reviewed articles which are summarised in Table 1.
We then developed an initial coding template that involved listing the authors, year of publication, paper title, journal name, CABS journal ranking, journal impact factor, and citations in Web of Science, Scopus, EBSCO, and Google Scholar. In addition, the research purpose, theoretical framework applied (if any), details on the methodology (e.g. method, sample, sector, level of analysis), key To examine fluctuations in the levels of work-family conflict and burnout COR theory ( Hobfoll, 1989) Empirical: quantitative, 66 surveys Conflict and burnout levels remains constant before, during, and after the trip for men; the level of conflict is lowest during and highest after the trip for women; burnout is highest pre-trip findings, and future research suggestions in the paper were all included. Our analysis of these data involved the adoption of an open coding process followed by the development of broader categories and resulted in the identification of our two core themesvalue creation and value destruction (see Appendix A for coding structure). In developing our core themes we applied a value lens (Bowman, 2010;Bowman & Ambrosini, 2000;Lepak, Smith, & Taylor, 2007) which allowed us to discern a deeper structure within our analysis, provide a conceptual platform for more explicitly integrating these studies with the broader IHRM context, and ultimately draw implications for effective management of FGWAs. The first theme encompasses strategic and organisational aspects such as the intra-and inter-firm functionality of these different forms of global work which describe value-creating activities. It discusses why organisations engage in flexible global work and includes open codes such as relationship building, position filling, knowledge transfer, leadership development, coordination and control, and negotiations, among others.
The second theme, value destruction, considers the more personal implications and highlights the potentially negative nature of these FGWAs. It refers to adverse physical, psychological, and social health and well-being consequences of being engaged in flexible global work. This theme includes open codes such as family, careers, support, work-life balance (WLB), workload, and stress, among others. The vast majority of papers are multi-authored (85 articles) and thus, the research stream is not dominated by a small number of scholars given there are 216 authors with 78 different first authors across the sample. In spite of the topic being so international in nature, the analysis demonstrates that cross-country author collaboration is uncommon with 72 articles produced by a single author or an author team from a single country. Based on the first author country affiliations, it is evident that the majority of articles are from Anglo-Saxon countries with 30 articles from the USA, 15 from the UK, 9 from Canada, and 7 from Australia. Other leading countries in terms of first author publications are Austria with 10 and Finland with 7 papers.

Publication profile
The articles have been published across a wide range of academic domains (see Table 2). Some 31 articles were disseminated in a journal that can be best categorised as HRM focused, followed by 22 articles in a medicine/health-focused journal and 22 articles in business-or management-focused journals. In addition, we also found journals that are focused on geography, psychology, tourism/ travel, community, education, economics, environment, innovation, international development, law, immigration, policy, and sociology. The articles in our sample were published in 62 different journals with the International Journal of Human Resource Management (13 articles), the Journal of Global Mobility (7 articles), and the Journal of Occupational and Environmental Medicine (6 articles) being the three most popular outlets. The majority of articles were published in journals with an impact factor (80 papers) and listed in the CABS journal rankings (74 papers).
While dominance of authors is not apparent, the citation data (see Table 3) tells us that there are clearly a small number of pioneering pieces that have gained the most interest among academics. One paper in particular stands out, namely, the Collings et al. (2007) paper has almost double the citations of the second most cited piece by Shaffer et al. (2012).

Table 2
List of journals and number of articles.

Methodologies employed
Our analysis demonstrates that the majority of articles (83 papers) are empirical in nature. Perhaps surprisingly given the recency of the topic in research circles, there is a good balance between the use of quantitative and qualitative approaches. This may however represent the multi-disciplinary nature of the publications and research design preferences in some fields. A total of 6 mixed method articles were found combining quantitative and qualitative tools (Dimberg, Mundt, Sulsky, & Liese, 2001;Jais, Smyrnios, & Hoare, 2015a, 2015bRoy & Filiatrault, 1998;Shortland, 2015;Striker et al., 1999). Out of the 36 qualitative articles, the majority used interviews, with a few articles combining interviews with some corporate documentation (Cardoso & Jordão, 2017;Haynes, 2010;Mayerhofer, Schmidt, Hartmann, & Bendl, 2011;Suutari et al., 2013) or focus groups (Pereira, Malik, Howe-Walsh, Munjal, & Hirekhan, 2017;Tahvanainen et al., 2005). Qualitative studies ranged from 5 to 120 interviewees. Out of the 41 quantitative articles, surveys were the most popular tool followed by an analysis of data from reports, appraisals, and medical records; 2 papers also used an experimental design (Phillips, Gully, McCarthy, Castellano, & Kim, 2014;Takahashi, Nakata, & Arito, 2002). The survey sample size varies significantly from a minimum of 66 to a maximum of 2233. The largest sample sizes represented those that involved the analysis of economic data and medical records. Of note was that several studies did not provide any or very limited information on their sample and only 50 articles provided a clear definition of the FGWA under consideration. Overall, we respectfully suggest that the quality of the empirical work and underpinning research design has scope for improvement.
Turning to the empirical context, we find that in 39 articles (47%), the research was conducted in a MNE setting of which 14 were single, and 25 multiple case studies. With the exception of three firms (based in Australia, India, and Japan), all of these MNEs were headquartered in Europe or the USA and in most cases the country equalled the first author's country affiliation. Thus, the research stream can be described as highly Anglo-Saxon focused in terms of study context, i.e. the organisations being researched. The limited research in more dispersed settings may also be due to the general lack of structured considerations around FGWAs by IHRM functions and organisations. Representing the research stream of flexible 'global' work without conducting research with organisations in other geographical regions such as Africa, the Middle East, and Latin America limits our understanding. Studies in those regions would provide a more holistic view on flexible global work challenges. In 28 articles (34%), individuals that were not linked to a particular organisation made up the sample, while there were 11 papers (13%) with research in a public sector environment. This setting was unexpected but can be explained as follows; 5 of these papers were based on data within the World Bank Group (Dimberg et al., 2001;Dimberg et al., 2002;Espino, Sundstrom, Frick, Jacobs, & Peters, 2002;Liese, Mundt, Dell, Nagy, & Demure, 1997;Striker et al., 1999); another 5 studies were conducted in universities (Crowne & Engle, 2016;Jais et al., 2015aJais et al., , 2015bJais, Smyrnios, & Hoare, 2015c;Salt & Wood, 2014), and 1 study was within the Irish Defence Forces (Crowley-Henry & Heaslip, 2014). In the remaining 5 papers (6%), regions and countries were the focus of research (Anderson, 2007;Belenkiy & Riker, 2012;Collins & Tisdell, 2004;Gholipour & Foroughi, 2019, 2020. We also considered the empirical context by sector. 34 out of the 83 empirical articles (41%) focused on one sector, 16 articles (19%) involved multiple sectors with 33 articles (40%) providing no details on sector. Most research was conducted in the banking, education, and IT sectors (6 studies each), followed by the oil and gas (5) and the energy (4) sectors. One study was completed in each of the following sectors: automotive, defence, engineering, pharmaceutical, professional services and consulting, purchasing, and telecommunications.
Reviewing the research design in more detail, we found that the vast majority of articles were at the individual level of analysis. Specifically, we found that in 63 out of the 83 empirical articles (76%), the unit of analysis was an individual, namely the traveller, commuter, assignee, or their spouse. Out of those studies, few had a balanced gender ratio while only two focused exclusively on Table 3 List of ten most cited articles. Citations as per 29 May 2020. women (Fischlmayr & Puchmüller, 2016;Miralles-Vazquez & McGaughey, 2015). One article focuses its analysis on a team level (McKenna, Ducharme, & Budworth, 2009) and 8 articles (10%) on a firm level of which only one had multi-source data that included flexible global workers, line managers, and HR (Suutari et al., 2013). As a result, we have limited knowledge on the interaction between individuals' experiences of flexible global work, other stakeholders, and the HR system. Five articles (6%) considered the impact of international business travel at a country level. The remaining 6 articles (7%) applied a combination of two units of analysis at individual, business unit, firm, sector, region, and country levels.

Flexible global working arrangements and theoretical framing
An important observation from the analysis was that while there has been increased discourse around the rise of these FGWAs, there is a clear imbalance in representation within the literature. Specifically, IBTs are the dominant focus accounting for 61% of all articles, followed by 10 articles on STIAs. Five papers focused on flexpatriates (Mayerhofer et al., 2011;Mayerhofer, Hartmann, & Herbert, 2004a;Mayerhofer et al., 2004b;Mayerhofer, Müller, & Schmidt, 2010;Pate & Scullion, 2018), and 2 on rotational assignees (Valk & Hannon, 2016. While referred to in other papers, no article had international commuters as the sole focus. The remaining 22 articles considered multiple types of global work with many also incorporating traditional expatriate assignments. Therefore, the evidence is not especially strong about the changing topography of global mobility in research intensity terms across each of the five different arrangements. It appears critical to clearly distinguish between the various forms of flexible global work as each is quite unique in its set-up (e.g. people, processes, and structures) (Reiche et al., 2019). As such, the differences between the various FGWAs have not been sufficiently discussed and we therefore know relatively little around the duties, responsibilities, and motivation of each FGWA. There also appears to be ambiguity around some of the terms with little consensus as to what they encompass. For example, it has been argued that flexpatriates may also include other sub-groups such as rotational assignees (Valk & Hannon, 2016) and project work assignees (Suutari et al., 2013). Referring to Wickham and Vecchi's (2009) taxonomy of travellers, Pate and Scullion (2018) view flexpatriates as an umbrella term including international commuters (repetitive journey, limited destinations), explorers (regular and new destinations), nomads (high number of new destinations), missionaries (to disseminate knowledge), and visiting tradesmen (to work on customer sites, e.g. project work). We argue that equating terms such as flexpatriates, international commuters, and rotational assignees is problematic as the set-ups of these forms of FGWAs differ (see Table 4). To better understand the actors, structures, and processes (Reiche et al., 2019) involved, we need to expand research of each form of global work and see subsuming terms on occasion as unhelpful for theoretical and practical reasons.
Building on recent insights around the phenomena of global work (e.g. Mäkelä, Barner-Rasmussen, Ehrnrooth, & Koveshnikov, 2019;Reiche et al., 2019), our review enables us to enrich Shaffer et al.'s (2012) framework, by presenting an extended classification which is mainly defined by duration, frequency, and location of global work (see Table 4). By doing so, we highlight international commuters and rotational assignees as two distinctive forms of flexible global workin addition to the previously presented IBTs, flexpatriates, and STIAs. The table also highlights the relational and structural embeddedness of flexible global workers through their capacity to act as boundary spanners.
Our analysis highlights an atheoretical approach across most papers with only 27 articles presenting some level of theoretical underpinning. This may reflect disciplinary and journal expectations. A total of 17 different theories were used in these articles thus indicating, to some degree, theoretical fragmentation. Most of these theories have focused on explaining the characteristics, experiences, and challenges of the individuals taking on flexible global work and predominately the potential value-destroying nature of it. Conservation of resources (COR) theory, job demands-resources (JD-R) model, effort-reward imbalance (ERI) model, holistic model of stress (HMS) and institutional theory were introduced to highlight some of the adverse health and well-being implications, particularly the role of stress. Social capital theory, social support theory, perceived organisational support (POS), and expectancy theory focused on the support systems perceived and requested by flexible global workers. Reasoned action theory and family systems theory were used to analyse the decision process of individuals when it comes to taking on flexible global work (Konopaske, Robie, & Ivancevich, 2005;Konopaske, Robie, & Ivancevich, 2009). In addition, role theory was introduced by Shaffer et al. (2016) to better understand role adjustment of individuals in their new family and work contexts, and Atkinson and Pareit (2019) examine the psychological contract of flexible global workers. Focusing on potential positive outcomes at an individual level, Dimitrova (2020) integrates principles from the challenge and hindrance demands (CH) framework with COR theory, while Andresen and Bergdolt (2019) discuss constructivist theory; both referring to the importance of developmental challenges as part of the FGWA.
In contrast, application of theory at an organisational level is especially scarce. We found only two papers that explain the value creation of flexible global work using a theoretical frameworksocial capital theory (Bozkurt & Mohr, 2011) and a combination of two microeconomic theories of the firm: managerial theory and the model for sales maximisation (Collins & Tisdell, 2004).

Value creation -Functionality of flexible global working arrangements
Flexible global work appears to have evolved as a valuable alternative to the conventional long-term international assignment and now forms part of many MNEs' global mobility portfolio (Wood & Salt, 2012). The contribution of these global work forms to organisations has been highlighted in the literature with a focus on value creation at both intra-and inter-firm levels (Bozkurt & Mohr, 2011). Flexibility, simplicity, and cost effectiveness are commonly described as major advantages of such global working arrangements (Shaffer et al., 2012;Shankaran, Murray, & Miller, 2011;Tahvanainen et al., 2005). However, such advantages are often assumed rather than proven. At an intra-firm level, a range of value-creating activities have been highlighted including staffing and position filling, relationship building with teams, knowledge acquisition and transfers, leadership and career development, research and development and innovation, coordination and control, project work and collaborative work, strategy meetings, problem solving, and seminars and trainings (Bathelt & Henn, 2014;Mayerhofer et al., 2004b;Welch, Welch, & Worm, 2007). Particularly in subsidiaries where suitable host country nationals are not available due to skills shortages, flexible global workers are seen as an important puzzle in the global staffing and knowledge transfer processes in MNEs (Collings et al., 2007;Welch et al., 2007).
Managing knowledge between HQ and subsidiaries has been identified in several papers as a key intra-firm function of flexible global work across MNEs (e.g. Bathelt & Henn, 2014;Minbaeva & Michailova, 2004). Miralles-Vazquez and McGaughey (2015) illustrate that flexible global workers can create, implement, and sustain innovation across various business units. Interestingly, their study also highlights the importance of socially embedded, informal interactions that lead to the generation of ideas and development of trust which ultimately underpin knowledge transfer. Minbaeva and Michailova (2004) suggest that the ability to transfer knowledge may be increased through involvement in FGWAs in multiple countries whereas conventional long-term expatriate assignments will align more on deepening knowledge within one location. This knowledge transfer ability appears to vary across the various forms of flexible global work. For example, limited value can be gained from a short, once-off business trip. Flexpatriates, on the other hand, can act as valuable global boundary spanners as they have particularly strong structural (connectedness) and relational (relationship quality) embeddedness across business units within a MNE (Mäkelä et al., 2019;Schotter et al., 2017;Taylor, 2007). They have a large network across various locations and are also able to develop meaningful relationships (Bozkurt & Mohr, 2011) with locals due to their extended stay. Consequently, they can be key actors in fostering inter-group relations, sourcing and sharing heterogenous knowledge (Criscuolo, 2005), linking people, and resolving conflicts (Björkman, Barner-Rasmussen, & Li, 2004).
Building on the idea of using distinct forms of global work for specific knowledge management purposes (Minbaeva & Michailova, 2004), a recent study by Duvivier et al. (2019) examines how using short-term international assignments to the HQ (short-term inpatriation), short-term international assignments to subsidiaries, and traditional expatriation allowed for the transfer of different types of knowledge. Initially, short-term inpatriates received declarative and procedural information including the job expectations and procedures, alongside some axiomatic and relational knowledge. Once inpatriates had returned to their subsidiaries, STIAs were sent to the subsidiaries to deepen knowledge transfer, intervene, and coach, mainly providing axiomatic knowledge. They conclude that forms of global work are ideally set up as 'a sequence of complementary knowledge transfer efforts' (Duvivier et al., 2019, p.188).
The literature also identifies the role of FGWAs in management development at an intra-firm level. Flexible global work takes place in an intense environment which requires employees to be agile, learn new global skills, and develop a global mindset (Suutari et al., 2013). This potentially provides a significant learning opportunity for flexible global workers. However, Oddou, Mendenhall, and Ritchie (2000, p.159) argue that this remains an under-utilised method as most managers 'cocoon themselves' during the time abroad, and thus, they are missing opportunities to enhance skills and do not invest in their personal growth. Atkinson and Pareit (2019) found that while IBTs expected their firm to provide development opportunities during business travel, they also acknowledged that it was their responsibility to realise the potential of such opportunities and to signal any career needs. This becomes particularly important when organisations view management development only as a peripheral benefit rather than the central cause of the FGWA, which may occur when it is organised around efficiencies and convenience (Oddou et al., 2000). Corporate travel policies and procedures that focus solely on operational measures including time and efficient use of financial resources lack strategic oversight (McKenna & Richardson, 2007). Ultimately, this means that firms do not fully capture the potential value of flexible global work in terms of leadership development.
Recent studies by Andresen and Bergdolt (2019) and Dimitrova (2020) reinforce the importance of considering how international business trips are organised. Integrating principles from the CH framework with COR theory, Dimitrova (2020) proposes that perhaps the trip purpose is somewhat less important in a development process. Instead, the work role and challenging experiences make the international business trip valuable. In other words, if adequately set up, development can be fostered during any form of flexible global worknot just during a dedicated leadership assignment. Similarly, Andresen and Bergdolt (2019) found that global mindset development depends significantly on how the international business trip is structured. Importantly, they highlight that an 'optimal level' of developmental challenges ought to be provided to ensure learning. As such, their role should encompass a balanced degree of novelty, uncertainty, and meaningfulness (Andresen & Bergdolt, 2019). At an inter-firm level, relationship building with partners, client and supplier meetings, negotiations and business development, promotions and sales events, problem-solving, and attendance at conferences, conventions, and exhibitions have been identified as value-creating activities (e.g. Belenkiy & Riker, 2012;Liu, Scholnick, & Finn, 2017). Engaging with stakeholders such as governments, professional bodies, or trade associations also requires significant travel to international meetings and trade fairs ). At both intra-and inter-firm levels, the continuing importance seems to be placed on faceto-face contact to create value across the operations in MNEs. Interestingly, advances in technology do not appear to have led to a reduction in travel Gustafson, 2012;Jones, Faulconbridge, Marsden, & Anable, 2018). While innovative technologies enable remote management and have prompted some to declare the 'death of distance', it appears that face-to-face contact remains important (Boeh & Beamish, 2012, p.533). Faulconbridge et al. (2009, p.298) refer to this phenomenon as the 'obligations of proximity' explaining that certain business contexts oblige people to travel, for example, to sign a contract, visit a building, or attend an event. In these scenarios, face-to-face encounters allow for understanding embodied interactions, gaining of social cues, and developing trust which are vital but often missed in a virtual environment (Dulebohn & Hoch, 2017). In addition, Mabey and Zhao (2017) highlight that particularly tacit knowledge is difficult to grasp through virtual means. Gustafson (2012) argues that virtual meetings may stimulate more global collaboration and consequently more face-to-face contact and Jones et al. (2018, p.257) conclude that 'virtual and physical work complement rather than substitute for one another'. The COVID-19 pandemic may of course substantially alter the intensity of use of FGWAs.
Drawing from social capital theory, Bozkurt and Mohr (2011) explain how flexible global work strengthens social ties by reducing organisational distances. Particularly IBTs and flexpatriates are highlighted as having the potential to initiate cross-unit ties with many colleagues and partners given their frequent travel to multiple locations. They also show a greater potential for the creation of valuable multilateral rather than bilateral social ties. Such ties help to develop valuable business partnerships, create shared values, and facilitate communication, ultimately creating value through the collection and dissemination of rich heterogenous knowledge from across the MNE Mäkelä & Suutari, 2009). However, the ties established by IBTs often remain weak when continuous and recurrent face-to-face interactions do not occur. Thus, international business travel may be more useful to sustain, deepen, and leverage networks rather than solely building them initially.
Ultimately, at both intra-firm and inter-firm levels, a range of activities can lead to value creation which subsequently contributes to the broader economic growth of organisations, regions, and countries. While not a core aspect of this review, we acknowledge that a few papers focus on such a wider economic impact (Anderson, 2007;Collins & Tisdell, 2004;Gholipour & Foroughi, 2019, 2020Hovhannisyan & Keller, 2015). For example, Hovhannisyan and Keller (2015) illustrate that increased international business travel leads to more innovation and subsequent patenting at a country level, and Anderson (2007) found that per capita GDP is higher in countries with higher inbound international business travel. Applying a combination of two microeconomic theories (managerial theory of the firm and sales maximisation model), Collins and Tisdell (2004) indicate a positive link between business travels and business returns. Drawing on the concept of microfoundations (Foss & Pedersen, 2019;Minbaeva, 2013) may aid to further explore the relationship between micro and macro constructs as part of the value-creating process.

Value destruction -Health and well-being implications
Traditionally, global mobility has been glamorised in society and an 'ominous silence' exists around its 'darker side' which, some may argue, still exists (Cohen & Gössling, 2015, p.1661. However, this review demonstrates increasing evidence of significant personal (stress and coping, identity transformation), work (career transition concerns, structural and perceptual barriers), and social (work-family conflict, maintaining friendships and personal life) demands for those undertaking flexible global work (Shaffer et al., 2012).
Some of the earliest articles that focused on physical health aspects were published two decades ago including a series of studies conducted at the World Bank Group on the impact of international business travel on the travellers' and spouses' health (Dimberg et al., 2001;Dimberg et al., 2002;Espino et al., 2002;Liese et al., 1997;Striker et al., 1999). For example, Liese et al. (1997) assert that international business travel poses a range of health risks beyond infectious diseases. More recent studies confirmed these concerns, for example, Rogers, Bunn, and Connor (2016) contend that health and safety risk are higher for IBTs across all categories of illness. Perhaps surprisingly, Bunn (2008) found that despite those significant risks identified by medical experts, many IBTs remain unaware of the risk of infection or do not follow recommendations provided. Common infectious diseases include: diarrhoea, influenza, yellow fever, typhoid fever, dengue fever, dengue haemorrhagic fever, malaria, hepatitis A and B, and human immunodeficiency virus (HIV) (Hudson & Fortuna, 2008). The COVID-19 pandemic represents an especially stark reminder of such physical health issues. Other frequent physiological costs include a disruption of the immune system, exposure to germs and radiation, jetlag, and sleep deprivation (Barish & Dilchert, 2010;Burkholder, Joines, Cunningham-Hill, & Xu, 2010;Cohen & Gössling, 2015). Harsh climate conditions and unhealthy living conditions with a lack of nutritious meals, an excess alcohol consumption, and a lack of exercise further strain the physical health of travellers resulting in a lower body mass index and lower blood pressure (Rezaei, Shahijan, Valaei, Rahimi, & Ismail, 2018). Dehydration due to low cabin air humidity, insufficient fluid intake, and restricted movement during flights may cause musculoskeletal pain or deep venuous thrombosis (DVT), a rare but painful health threat particularly of concern for IBTs and international commuters due to the high frequency of travel (Chen et al., 2018;Druckman et al., 2014). Overall, it appears that medical and insurance claims were considerably higher for travellers than for non-travellers and increased with frequency of travel thus bringing a value-destructing component (Dimberg et al., 2002).
From a psychological aspect, the early studies conducted at the World Bank Group focused on stress levels of IBTs. It was found that IBTs experienced higher levels of stress as a consequence of lengthy travelling and frequent changes in travel dates (Espino et al., 2002). Psychological costs included not only increased stress levels but also in extreme cases psychological disorders and mental illnesses (Cohen & Gössling, 2015). Valk and Hannon (2017) found that 36% of IBTs reported high or very high stress levels. This is linked to a range of factors including dual commitments in home and host countries, anxiety of an accumulating workload, pre-trip stress, transportation, sensory overload, isolation and loneliness, and a personal identity confusion (Burkholder et al., 2010;Richards & Rundle, 2011). Most positions that encompass substantial flexible global work engagement do not consider the additional duties and responsibilities that go beyond the conventional home-country job description (Kraimer, Bolino, & Mead, 2016). As a result, employees are seen juggling their dual workloads in home and host countries, working extremely long days in the host country in order to 'catch-up' with work back home. Reference also exists to the host country adjustment particularly where high institutional distances are evident (Ramsey, 2013). Both instances are causes of high levels of stress and can impact an individual's performance and ability to create value for the organisation.
From a social aspect, it must be acknowledged that FGWAs inevitably affect the personal life of employees including their kinships, friendships, and communities (Cohen & Gössling, 2015). Some scholars refer to work-life imbalance as a potentially 'desired state of working life' (Mayerhofer et al., 2011, p.605). For the ambitious and driven individuals that accept this imbalance, being engaged in flexible global work is viewed as a career fit and long-term rewards are a positive prospect. However, for many global workers, worklife imbalance appears to lead to conflicts that ultimately impact health and well-being and can therefore be described as a valuedestructing activity.
Career choices are naturally related to internal influences such as intrinsic and extrinsic motivators and personal characteristics (Shaffer et al., 2012). Drawing from reasoned action theory, Konopaske et al. (2009) found that external influences such as personal agency, country and family considerations significantly impact these choices. Although most of the FGWAs do not require relocation, spouses' and families' general approval engaging in such work still plays a crucial role in the decision process to take it on. Drawing from family systems theory, which asserts that individuals cannot be assessed in isolation but as part of their families as these build an emotional unit,  found that spouses' willingness to relocate exerted a positive influence on managers' willingness to take on a short-term international assignment. In contrast, spouse job involvement was the most significant negative predictor of willingness to relocate.
While it could be argued that flexible global work is easier to manage from a family perspective compared to conventional expatriation, our review shows that the work-family conflict remains a key concern among many employees (Suutari et al., 2013). Ultimately, a significant amount of time is spent away from families, and work schedules are often unpredictable (Baker & Ciuk, 2015). Flexible global workers have only limited control over their schedules and many trips are taken on very short notice depending on customer demands and internal business requests. Due to the lack of strategic oversight, the employees are commonly left alone in managing these trips with global travel departments, where in existence, being the only function involved (Mayerhofer et al., 2004b). Moreover, given the unstructured nature of this work, travel decisions are made at line managers' discretion across operational departments which adds further ambiguity to the process (Welch et al., 2007).
In addition, emotional exhaustion as a result of extensive travelling has also been highlighted as regularly leading to work-family conflict (Jensen & Rundmo, 2015;Mäkelä, Bergbom, Tanskanen, & Kinnunen, 2014;Mäkelä, Kinnunen, & Suutari, 2015). The lack of clear boundaries may result in role blurring and subsequently in potential conflict which can hinder value creation in MNEs (Demel & Mayrhofer, 2010;Saarenpää, 2018). Drawing from role theory, Shaffer et al. (2016) contend that a certain level of comfort with the responsibilities and relationship interactions within new or redefined work and family role must be achieved. Being absent from home can cause a loss of the family role and little time for home-based social life which ultimately means scaling back of one's home network (Richards & Rundle, 2011).
A particular interest among some scholars has been the role of women as flexible global workers, wives, and mothers. Studies show that traditional gender role patterns still exist in some contexts and that women face prejudices when wanting to combine family and an international career (Fischlmayr & Puchmüller, 2016;Westman et al., 2008). For example, Mayerhofer et al. (2004a) found that while career issues were evident for all flexpatriates, the impact of family life was viewed as more significant for women. Investigating the role of social capital, Fischlmayr and Puchmüller (2016) contend that women may use their social capital to organise their career, family life, and childcare. However, FGWAs that involve considerable travelling such as international business travel and international commuting are unpopular among women as their working patterns are disruptive to WLB, particularly for mothers (Shortland, 2015). This confirms earlier findings by Casinowsky (2013) who found that men typically engage more in international business travel than women. Women appear to remain the main caretaker for children when engaging in flexible global work, and childcare was identified as the number one challenge for women (Fischlmayr & Puchmüller, 2016). However, it must be pointed out that other studies have questioned some of the stereotypes related to women's ability to engage in flexible global work. For example, Mäkelä, Bergbom, Saarenpää, and Suutari (2015) found that women without dependent children were at the lowest risk of work-family conflict in a mixed-gender sample.
Given the significant physical, psychological, and social challenges faced by flexible global workers and their families, a combination of informal and formal support is required (Dimitrova, Chia, Shaffer, & Tay-Lee, 2020). However, our review indicates that due to the lack of oversight from subsidiary or corporate level HRM functions, very limited support appears to be provided in most instances (Conroy, McDonnell, & Holzleitner, 2018;Suutari et al., 2013). Drawing from expectancy theory, Konopaske and Werner (2005) present a range of support types requested by employees undertaking flexible global work including on-site assistance, development opportunities, aligned compensation, and career prospects. Similarly, Jais et al. (2015a) differentiate between organisational, HR, financial, and career support. Taking COR theory into consideration, Jensen and Rundmo (2015) contend that organisational resources are critical to support IBTs which will reduce job exhaustion. Based on the JD-R model, Mäkelä and Kinnunen (2018) also highlight the consequences of insufficient resources and guidance by firms on health problems and job performance. Particularly in a high institutional distance context, resources need to be provided. From a physical health aspect, offering adequate medical insurance, vaccination, and prevention programmes is required (Rogers et al., 2016;Rogers, Bunn, & Lerner, 2019) and organisations should identify those employees at risk (Druckman, 2009). From a psychological aspect, preparing for the stress factors that often accompany flexible global workers is essential (Burkholder et al., 2010). It appears that pre-travel advice is still underutilised and needs to be improved considerably in organisations (Chen et al., 2018). Informal support pre-departure and postarrival may include the establishment of network ties in the local country with other assignees or host country nationals while formal support is mainly provided pre-departure and may include language and cross-cultural training (Conroy et al., 2018). Gaining such broader cultural intelligence may reduce cross-cultural adaptation stress on arrival in the host country and limit potential valuedestructing inter-cultural conflict when managing and negotiating across international operations (Crowne & Engle, 2016;Ramsey, Leonel, Gomes, & Monteiro, 2011).
Despite families being acknowledged as a critical success factor for flexible global workers, WLB support factors have not adequately been discussed to date (Shaffer et al., 2016). Focusing on a sample of female IBTs and drawing from social support theory, Puchmüller and Fischlmayr (2017) found that women mainly valued and used emotional and instrumental support; however, they did not target informational support. Regardless of gender, organisations are under pressure to consider an individual's family status (Mäkelä, Bergbom, et al., 2015) and lifestyle (Mayerhofer et al., 2010), allow lead times and flexibility (Lirio, 2014), and facilitate efficiencies in work administration (Mayerhofer et al., 2011) in order to limit the value-destructing nature of flexible global work.

Integrating flexible global work in a strategic IHRM context
Despite the various contributions of FGWAs, limited evidence exists around their strategic integration with the IHRM structures within MNEs. Research appears to indicate that most FGWAs are disconnected from the broader IHRM structure with little oversight from corporate HR functions (e.g. Suutari et al., 2013), which we posit hinders the value-creating capacity of such work. Particularly in the context of skills shortages in many countries, flexible global workers may best be viewed as critical employees and actively managed at a corporate HR level (Collings, 2014). This situation appears in spite of having identified the management of internal receptivity (i.e. talent flow and career management) as a core responsibility of the corporate HR function in MNEs (Farndale, Scullion, & Sparrow, 2010).
As MNEs seek to establish more innovative and adaptable IHRM systems, policies, and practices, FGWAs have the value-creating capacity to strike an effective balance between global integration and local adaption of its IHRM structures (Pudelko & Harzing, 2007). Regardless of whether MNEs focus more on global or regional strategies, flexible global workers can navigate and oscillate between global, regional, and local levels. If leveraged effectively, they have the potential to operate as a strategic platform through which the corporate HR function becomes a spearhead in creating a more 'integrative' IHRM model (Minbaeva, 2013). Rather than relying on expatriation of parent country nationals, which often results in the implementation of globally standardised IHRM structures, FGWAs provide MNEs with a more formative way to control foreign subsidiaries, while maintaining sufficient autonomy to learn and adapt local HR practices (Hitt et al., 2016). In more complex MNE structures, FGWAs may provide the HQ with a subtle yet influential way to coordinate globally dispersed subsidiaries, building high-bandwidth communication channels with subsidiaries in peripheral locations, and deepening the integration and assimilation of best practices across the MNE. With the growing significance of regional strategies for MNEs, scholars should consider how FGWAs provide regional HQs with a strategically valuable mechanism for balancing complex tensions between underperforming or self-interested subsidiaries in a local context and rationally bounded or over-controlling corporate HQs in the home country (Conroy, Collings, & Clancy, 2017;Preece, Iles, & Jones, 2013). Scholars should also look to explore how different portfolios of FGWAs may align with various types of international strategies outlined in Bartlett and Ghoshal's (1989) integration-responsiveness framework. It is likely that MNEs with transnational strategies, that rely on multidirectional flows of personnel, capital, and knowledge provide a suitable context to examine the double-edged sword of FGWAs. As such, a more explicit acknowledgement of and accommodation for FGWAs will refresh and update the IHRM field, aligning it more closely with contemporary practitioner debates in 'talent mobility' (Deloitte, 2019). This requires more frequent and intense dialogue between scholars in IHRM and international business to unpack the strategic importance of IHRM and more precisely the value-creating nature of FGWAs (Reiche et al., 2019).
Recent work on global boundary spanning also provides us with a context to theorise the value-creating capacity of FGWAs in MNEs. Although some studies have considered the boundary spanning roles of expatriates (Liu & Meyer, 2020), flexible global workers confront unique circumstances in that the limited duration they spend in any given market means they may have to endure to maintain trust and legitimacy across a broad range of networks (Bathelt & Henn, 2014). While expatriates are confronted with relatively stable boundaries rooted in a single location, flexible global workers regularly traverse geographical, cultural, and hierarchical boundaries, which presents a multiplicity of boundary frictions, making their boundary spanning role more intricate and complex (Schotter et al., 2017). However, they can potentially perform significant gatekeeping, connecter, and bridging roles (Pedersen, Soda, & Stea, 2019;Yagi & Kleinberg, 2011). Although recent studies have sought to expand the knowledge-related activities of alternative forms of mobility (Duvivier et al., 2019), more research is required on the boundary spanning activities of flexible global workers. For instance, in the early stages of location investment decisions, flexible global workers may be deployed as reconnaissance scouts, identifying suitable sites, collecting contextually valuable information, and building social capital locally to determine appropriate entry modes. In the context of a continuously increasing spatial division of labour, we suggest emerging insights from global strategy scholars on the significance of global boundary spanning (e.g. Pedersen et al., 2019) provides a fruitful and relevant context to draw from.
Studies should also look to situate the value-creating capacity of flexible global work in the context of recent arguments on global talent management (Cascio & Boudreau, 2016). For instance, it is likely that many undertaking flexible global work are talented individuals, operating in pivotal positions and accumulating valuable firm-specific human capital (Morris, Snell, & Björkman, 2016). Exploring FGWAs through a human capital lens may provide scholars with a way to more effectively integrate insights on international business and IHRM. For instance, different forms of MNE human capital, such as corporate human capital or subsidiary human capital (Chung, Park, Lee, & Kim, 2015;Morris et al., 2016) can be leveraged through various FGWAs to balance global integration and local responsiveness demands. Consequently, engaging in flexible global work may allow individuals to strengthen their position in a global talent pool or act as a springboard for global talent designation in the future which, in turn, allows MNEs to maintain their global talent supply (Collings, Mellahi, & Cascio, 2019). However, it can be argued that human capital on its own is insufficient and that other forms of intellectual capital such as social, political, cultural, and career capital are required (Harvey & Novicevic, 2004;Ng, Tan, & Ang, 2011). While recent studies have explored learning and competence development as part of FGWAs (Andresen & Bergdolt, 2019;Dimitrova, 2020), research on global careers remains scarce. Having been applied in the research streams of traditional expatriation (Dickmann & Doherty, 2008) and self-initiated expatriation (Al Ariss & Crowley-Henry, 2013), career capital has the potential to provide further insights into the significance or otherwise of FGWAs on individuals' careers (Demel & Mayrhofer, 2010). Work from Stahl, Miller, and Tung (2002) and others (e.g. Bolino, 2007;Rodrigues & Guest, 2010) on the concept of 'boundaryless' careers could also prove fruitful in this space. For example, building on the work from DeFillippi and Arthur (1996), FGWAs may facilitate 'knowing how, knowing whom, and knowing why' career competencies of individuals by developing cross-cultural skills, broadening their network in the MNE, and understanding their own identity. From a theoretical perspective, this would see us broadening the limited theoretical base that currently exists for flexible global work, that focuses largely on microeconomic theories and perhaps narrow capital views to broader considerations of value creation including integrative IHRM, global boundary spanning, and global talent management.

Sustainable solutions for more flexible global work
Despite the potential value-creating capacity of flexible global work, our review reported that these arrangements present a doubleedged sword in that, if not appropriately supported, they may destroy value within the MNE over time. We posit that this value destruction manifests largely at the individual level, in that flexible global work may have significant negative consequences for the individuals performing such roles. Therefore, MNEs need to create and develop structures and systems to ensure that FGWAs offer a more sustainable career path for individuals that undertake this kind of work. Emerging insights from sustainable careers studies (De Vos, Van der Heijden, & Akkermans, 2020; Straub, Vinkenburg, & Van Kleef, 2019) could prove useful for further exploring how flexible global work hinders or contributes to the personal development and overall physical or mental well-being of individuals involved in this work over time. Specifically, ability, engagement, and performance in terms of health, happiness and productivity are important factors in assessing the 'sustainability' of flexible global work. Flexible global work is therefore a dynamic and multifaceted context to explore the sustainability of one's career, particularly as it also requires the active involvement of other salient stakeholders such as families and peers (Mayerhofer et al., 2004b). The lens of sustainable careers may be particularly fruitful in exploring how organisations support females and mothers in sustaining this type of work over time. However, further empirical research is required to understand how individuals cope with the associated challenges and how their personal characteristics, past experiences, and family characteristics impact their intention to take on (further) flexible global work.
Future studies should also seek to differentiate between the various forms of flexible global working and test if the assumption that more frequent travel leads to higher susceptibility to health and well-being implications holds true . From a theoretical perspective, this would see us broadening existing approaches that focus on the individual worker towards models of occupational health. Examining the measures that can be taken to reduce health and well-being implications should be viewed as a critical area of concern. This has become all the more aggravated and apparent in the current COVID-19 crisis when public health is a most prominent topic. Undoubtedly, workplaces directly impact physical, psychological, and social well-being of employees (Danna & Griffin, 1999) and creating truly healthy workplaces has been a strategic priority for many organisations in recent years (Guest, 2017). Although studies have considered HR's role in managing broader duty of care and WLB issues (Lirio, 2014), these issues are largely absent in the context of IHRM. For instance, work on 'health and safety rules' (Mayerhofer et al. (2004b(Mayerhofer et al. ( , p.1380 in 'high risk' locations those where crime, terrorism, civil unrest, and armed conflict are presentemphasises how duty of care is provisioned in the form of security and emergency aid for assignees (Bader, 2015). Ignoring the call for greater support will certainly create ongoing ambiguities and misunderstandings between flexible workers and employers, and potentially trigger a psychological contract violation (Pate & Scullion, 2018) hindering the sustainability of such arrangements over time. In contrast, a strong health and security culture and duty of care principles in organisations can enhance desirable prevention behaviour and the overall experience of flexible global workers (Berg et al., 2011). As we demonstrate in our review, future studies should seek to collaborate with multidisciplinary fields such as psychology and medicine in particular to more fully appreciate the cognitive and physiological effects of flexible global work over time (Mäkelä & Kinnunen, 2018).
More empirical work and clarity is also needed on the impact of broader contextual factors particularly cultural and institutional differences between home and host countries on the sustainability of FGWAs. Given the significant challenges flexible global workers face in bridging cultures between home and host countries there is a need for scholars to explore the scaffolding supports for these in continuously adjusting to a diversity of cultural settings. Specifically, we have a limited understanding of how existing pre-departure training programmes for expatriates are redesigned, tailored, and adapted to account for issues of cultural diversity and multiplicity across a broad range of contexts (Conroy et al., 2018). Performing flexible global work effectively requires a highly diversified skillset involving language proficiency and cultural intelligence as well as being socially and politically adept in addressing complexity, contradiction, and conflict. It may also be useful for scholars to explore how effective bicultural or multicultural individuals are in performing this type of work or even how individuals develop multiple cultural identities when carrying out flexible global work over time (Lücke, Kostova, & Roth, 2014). These issues may have broader implications on how individuals are selected for certain forms of flexible global work but to date there is very little research in this area.
Equally, broader disruptions in the geo-political, socio-economic, and health landscape can disrupt the deployment and flow of flexible global workers to certain locations, so it is important to explore how MNEs adapt their portfolio of arrangements to accommodate these contextual shocks. The COVID-19 pandemic has led to travel restrictions across the globe and has seen MNEs turn towards virtual substitutes. Even with travel bans being lifted gradually, perceptions towards FGWAs may change among mobile employees and organisations (Caligiuri et al., 2020). As such, another potential way that MNEs can look to support and sustain this type of work is by developing a more sophisticated virtual architecture that acts as a complement to how individuals sustain the amount of flexible global work they carry out. This may require organisations to enhance their technological infrastructure and upskill workers that need training and development in utilising these forms of communication. Although much work has been carried out on the challenges and effectiveness of global virtual teams (e.g. Kramer, Shuffler, & Feitosa, 2017), more empirical research is needed on the way in which virtual platforms and remote working can be leveraged to create a more sustainable scenario.
Organisations may benefit from considering more comprehensively the actual benefits from their use of FGWAs. Relatedly, we posit that balancing flexible global work with virtual based interactions will help in offsetting grand challenges on environmental sustainability and climate change in that MNEs will engage less in frequent business travel, unless it is a strategic imperative. More research is needed on the significance of flexible global work and its relationships with, or impact on, global climate change. This issue also requires a multidisciplinary approach from IHRM scholars that could, for example, draw from work on Climate Science and Environmental Geography in addressing how FGWAs are more effectively deployed and utilised. Ultimately, there are many fruitful avenues to further advance knowledge on FGWAs in terms of its link to sustainable careers, IHRM support structures for health and well-being, virtual platforms, and broader climate change issues.

Conclusion
In recognising the ever-shifting boundaries of global work and addressing the existing shortcomings in current studies on global mobility, this paper provides a systematic review of and research agenda for FGWAs. While the IHRM literature focuses on expatriate management (Cooke et al., 2019), alternative forms of global working have increasingly been employed by MNEs (Deloitte, 2019) due to a need for greater flexibility. Despite significant potential value identified (e.g. relationship building, knowledge transfer, and leadership development), there appears to be a distinct lack of strategic linkages to the IHRM function which we argue severely limits the value-creating capacity of these forms of global work. In addition, the research illustrates many concerning health and well-being implications that can emanate from these work arrangements, but there is no evidence as to how these are considered by organisations.
We conclude that the research stream of flexible global work is still in its infancy, and while several important studies have been published in the past two decades, further empirical and conceptual research is required. Moreover, methodologies employed so far provide scope for improvement and elaboration. Given the emergence of new frontier economies, research on the importance of context (Cooke, 2018) and considering more dispersed geographical regions would also add to a more holistic approach towards FGWAs. Considering gender perspectives (De Cieri, 2009) more closely would similarly contribute to such an approach. To date, theoretical development is scarce in this research stream. Given the wide range of questions addressed as part of the flexible global work discussion and the different foci on individual and organisations, which arguably require different perspectives and theories, it is somewhat understandable that no single theory dominates. There is however a need for further theorisation and conceptualisation, particularly considering a multiplicity of intellectual capital lenses and holistic occupational health frameworks. The trajectory of research to date is positive in that a multi-disciplinary approach has been applied. The review demonstrates the relevance of FGWAs for domains beyond HRM and therefore offers opportunities for much more multi-disciplinary research. As internationalisation strategies, foreign direct investment location choices, and ownership strategies are becoming more complex in MNEs (Belderbos, Du, & Goerzen, 2017;Verbeke & Kano, 2016), FGWAs should be considered across a range of fields including IHRM, international business, global strategy, economical geography, supply chain management, and risk management, among others. This would arguably lead to greater 'comprehensiveness, connectedness and complexity' (Sullivan, 1998, p.837) and perhaps creativity (Buckley, Devinney, & Louviere, 2007) when researching the phenomena of global work.
At the same time, there is a need for caution not to disconnect FGWAs from HR. More so, we suggest a stronger integration with strategic IHRM, noting that organisational settings and the global work itself have not been adequately discussed. While there is undoubtedly more empirical and conceptual research required on the individuals themselves, we emphasise a need for more research at business unit and organisational levels to better understand policies and procedures in MNEs and their implementation across subsidiaries. We therefore propose a more balanced research agenda taking on a mutual-benefits perspective (Farndale, Pai, Sparrow, & Scullion, 2014); considering the views and experiences of individuals on FGWAs, while at the same time securing effective implementation and a better understanding of the HR function's role and responsibility. Ultimately, in responding to volatile and ambiguous changes, MNEs need to balance the double-edged sword of FGWAs, in developing a strategic and sustainable approach to enhancing the value-creating capacity of its global workforce.

Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.