| Human and relational | Hitt et al. (2006) | To study the influence of human and relational capital on internationalization | 52 largest U.S. law firms by total revenue | Law firms | 1992–1999 | Human and relational capital | Number of foreign offices and the number of lawyers in each office | LSDV model involving a generalized least squares estimation, 1 year time lag between variables | The extent of human and relational capital generally had a positive effect on internationalization. |
| Structural | Filatotchev and Piesse (2009) | Interrelationship between post-flotation R&D efforts and internationalization | 1 110 IPO’s from UK, Germany, Italy and France | Various, excluding financial sector | 1985–2004 | R&D intensity | Export growth | Regression analysis, control variables included | R&D intensity positively influences internationalization. |
| Intellectual | Li et al. (2012) | Role of R&D, advertising, international experience, and alliance in the early internationalization | 278 US STEs | Biotech products, computer products (peripherals and components), electronics, semiconductors, software, telecommunications, test and measurement equipment, transportation equipment | 2004–2009 | R&D intensity, advertising intensity, international experience, forming alliances | Early internationalization understood as establishing foreign operations within 3 years or less of their founding | Regression analysis, control variables included | Early internationalization is positively influenced by R&D intensity, whereas advertising intensity and alliance formed are not significant. Relation between international experience and degree of internationalization takes an inverted U-shape. |
| Human | Brambilla et al. (2012) | To study how exports and export destinations affect the utilization of skilled labor | 901 Argentinian firms | Manufacturing | 1998–2000 | Wage levels | Export intensity with the division on destinations based on income | OLS, control variables included, robustness test checked | Exporting to high-income countries induces firms to hire more skilled workers, but exporting per se does not. |
| Structural | Altomonte et al. (2013) | To identify correlation between innovation intensity and internationalization | 14,759 large firms from Austria, France, Germany, Hungary, Italy, Spain, and UK | Manufacturing | 2008 | R&D financial incentives, R&D-related tax allowance | Exports, imports, FDI, outsourcing | OLS, control variables included, robustness test checked | Unit increase in innovation intensity leads to an average increase of around 0.3 in internationalization intensity. No significant cross-country differences are observed. |
| Human and structural | Teixeira and Coimbra (2014) | To study the impact of structural and human capital on the internationalization speed of USOs | 111 Portuguese USOs | Energy/environment/sustainability, bio/pharma, medical devices/diagnostics, microelectronics/robotics sectors, ICT/software/digital media, agri-food | 2012 | Experience, education, R&D intensity, no. of patents registered | Time lag between the founding of the firm and the firm’s first international operations | OLS, control variables included | Technical skills of entrepreneur affect speed of internationalization positively and R&D intensity negatively. No significant impact of patents registered. |
| Human and structural | Mohr and Batsakis (2014) | Impact of intangible fixed assets and international experience on internationalization speed | 144 global firms (majority from USA, UK, Japan, Germany, France) | Retail | 2003–2012 | Intangible fixed assets, depth and breadth of international experience | Speed of internationalization (average number of foreign outlets divided by the number of years since the firm’s first international expansion) | Generalized least squares (FGLS), control variables included | Intangible assets, depth, and breadth of international experience perform a positive effect on the speed of internationalization. |
| Intellectual | Moisés et al. (2014) | To determine the role of intangible assets in born globals and Uppsala models firms | 3,690 firms from 80 countries | Various | 1999–2000 | Tobin’s q | Export intensity | Tobit regression, control variables included | Intangible resources are more important for the performance of the born globals than for the Uppsala firms. |
| Human | Lafuente et al. (2015) | Impact of intangible assets on likelihood of export entry and export sustainability | 319 Romanian SMEs | No information | 2008 | Managerial studies, labor experience, presence of an entrepreneurial team, perceived risk | Probability of export entry and export sustainability | Multinomial logit regression, control variables included, robustness test checked | Completion of management studies and existence of entrepreneurial team increase the probability to engage in exporting. Labor experience foster export sustainability. |
| Human and structural | Rodríguez and Nieto (2015) | Impact of innovation capability and cooperation on the propensity to internationalize | 1,839 Spanish firms | Knowledge-intensive business services (NACE M72, M73, M74) | 2003–2005 | R&D intensity, training expenses, R&D personnel | Export intensity | Probit model, control variables included | R&D expenditures and cooperation with other firms and/or institutions positively affect export growth. |
| Human | Bell and Cooper (2015) | To study the role of intangible assets in the internationalization | 9 Canadian SMEs | Pharmaceuticals | No information | Entrepreneur background, knowledge, networking activities | Number of countries internationalised | Multiple case study | Most studied companies evaluated entrepreneur background, knowledge on foreign markets, and networking activities as vital factor of internationalization. |
| Human and structural | Panda and Reddy (2016) | Impact of human capital, advertising, and brand investments on internationalization | 46 public and private Indian banks | Banks | 2008–2012 | Number of employees, advertising, and brand investments | International advances and borrowing intensity number of countries served | Pooled OLS, control variables included | Intellectual capital has a significant positive influence on the internationalization of banks in terms of international advances intensity and number of countries served. Advertisement and branding expenses are significantly negatively related to the international borrowing intensity. |
| Human | Onkelinx et al. (2016) | The role of firm-level human capital in the internationalization of SMEs | 5,800 Belgian SMEs | Manufacturing | 1998–2005 | Weighted average education level of newly hired employees and the average wage level of all employees | Export intensity | Hierarchical Tobit regression, control variables included analysis 1 year time lag | Findings indicate a significant curvilinear (inverted U) association between the level of human capital and the firm’s export intensity when firms choose a strategy of accelerated internationalization. |
| Human | Almodóvar et al. (2016) | The role of human asset quality in the internationalization of SMFEs | 610 Spanish SMFEs | Manufacturing | 2006–2010 | Weighted average education level, R&D staff ratio | Export intensity | Tobit panel data analyses, control variables included | Relation between education level of the employee base, ratio of R&D staff to total employees, and internationalization take an idiosyncratic S-curved shape. |
| Intellectual | Danik et al. (2016) | To study motives of early internationalization | 10 Polish SMEs | Various, nonfinancial | No information | Founders background, knowledge, personal relations network, experience | Funding born global and early internationalization process | Multiple case study, descriptive statistics | International “vision,” previous experience, and strategy of the management are very important in funding a born global firm and later internationalization process. |
| Human | Arte (2017) | To examine the role of experience and knowledge in new venture internationalization | 6 Indian SMEs | Various, nonfinancial | 2015 | Experience, market and technological knowledge | INVs | Multiple case study | International, entrepreneurial, and industry experience are perceived as the important factors in the process of internationalization along with the market and technological knowledge. |
| Intellectual | Jardon and Molodchik (2017) | To explore the role of intellectual capital in each phase of the process of internationalization | 1,687 Russian firms | Manufacturing | 2013–2014 | Education, internal coordination system, cooperation (various forms) | Six staged internationalization index (within the framework of the Uppsala model) | Logistic regression, control variables included | Cooperation (in its various forms) is the most important determinant of internationalization at all stages, followed by structural capital. |
| Structural | Cieślik and Michałek (2018) | To determine the relationship between different forms of innovation and their export performance | 1,374 firms from Poland, Czech Republic, Hungary, Slovakia | No information | 2011–2014 | Process, product, management and marketing innovation, R&D spending | Probability of export initiation | Probit model, control variables included | Only process innovations, R&D spending, and employees with higher education positively affect export likelihood. |
| Human and relational | Baier-Fuentes et al. (2018) | Impact of human and relational capital on rapid internationalization | 3,425 entrepreneurs from Spain and Chile | No information | 2013 | Entrepreneurs’ formal education, entrepreneurial experience, risk perception, entrepreneurs’ network, entrepreneurial team, business angels’ involvement | Rapid internationalization understood as INVs | Regression analysis, control variables included | Positive influence of formal education. No link between entrepreneurial experience/risk perception, and rapid internationalization (Spain). In the case of Chile, all three human capital measures positively influence rapid internationalization.Positive influence of entrepreneurs’ networks, teams, and participation as a business angel (Spanish context only). |
| Intellectual | Éltető and Udvari (2018) | To determine the factors enhancing internationalization | 148 Hungarian SMEs | No information | 2016–2017 | Commitment of the own management, knowledge on the market, language skills, technological development | Export intensity | Descriptive statistics, case study | Commitment of the own management, knowledge on the market, language skills, and technological development were the most important intangible factors contributing to the successful internationalization. |
