2.1. Economic complexity and income inequality
As a robust predictor of economic growth, economic complexity implies the improvements of various crucial socio-economic constructs, including institutions and human capital (Hartmann et al., 2017). Due to the complex interrelationship among socio-economic factors, progressing to a sophisticated economy could either narrow or widen income disparity.
On one hand, the literature document two primary ways that economic complexity could lessen income inequality, including narrowing the income gap between workers and capital owners and equalizing occupational opportunities among workers. First, an individual’s income may come from two main sources, including capital and labor. Therefore, income inequality is affected by the distribution of economic rewards to the agents of these factors. This, in turn, depends on the distribution of labor and capital in the society and how the output is shared between these two factor endowments. As capital is distributed more unequally compared to that of labor, the rise of labor share, as proxied by the proportion of wages and salaries in total GDP, may lead to lower income disparity (Daudey and Garcia-Peñalosa 2007). The development of a highly complex economy requires the inputs of tacit knowledge that is embedded in labor (Young and Zuleta 2016). Since acquiring this productive knowledge for making diverse and unique products is a costly and risky process, not only the demand for labor but also the workers’ bargaining position will increase during the economic complexity evolution. Moreover, participating in a complex productive economy with high productivity will increase return to scale (Constantine 2017, Lee and Vu 2020). This would further raise the labor share in total output (Young and Tackett 2018, Knepper 2020) and hence, shrink income inequality between capital holders and workers (Arif 2021). Second, since productive knowledge is embedded in the diversity and ubiquity of a country’s export, economic complexity implies the diversity and ubiquity of production capabilities that a society attains. In this regard, a country with low economic complexity is characterized by peripheral production where there is a limited connection among products. Therefore, not only are the number of business sectors limited but also low opportunities for other economic activities are left (Elgin and Oztunali 2014). As a result, there are limited occupational choices while the national wealth is obtained by small groups in the society (Constantine and Khemraj 2019). When the economy is more sophisticated, the combination of more diverse and unique productive knowledge allows the introduction of new products. The denser product space induces more production activities across sectors. Consequently, the highly complex economy would demand more labor with dispersed skills and various levels of knowledge (Constantine and Khemraj 2019, Hartmann et al. 2017). During the initial phase of economic complexity revolution, the low-skilled segment could obtain more benefits from a flatter occupational structure with more job and learning opportunities compared to the high-skilled counterparts (Albassam 2015, Egger and Etzel 2012, Hartmann 2014, 2017). This, in turn, facilitates the achievement of a more equal society. Moreover, a highly complex economy could facilitate a higher level of specialization to achieve better production efficiency. This favorable economic condition could be sustained in the long term since an economy with diverse production activities is more resilient from economic shocks (Barnes et al. 2015, Joya 2015). Overall, the poor could get better lifetime earnings that could be used to immediately either improve their living standards or invest in health and education. This helps resolve poverty, enlarges the middle-income class, and reduces income inequality in the long run (Constantine 2017, Hartmann et al. 2017, Hidalgo 2015). Hartmann et al. (2017) provide empirical evidence about the contribution of economic complexity in equalizing income based on a data set of 150 countries from 1963 to 2008 and Le Caous and Huarng (2020) over 87 developing countries during 1990-2017.
On the other hand, a rising income gap either between workers and capital owners or among workers of different skill levels could be also witnessed in a country with high economic complexity due to several reasons. First, when economic sophistication reaches a sufficiently high level, technological advancement may facilitate the substitution of capital for labor. In this regard, the overall occupational opportunities and the bargaining power of workers may reduce. This is followed by lower labor share, and hence, higher income inequality between workers and capital owners (Arif 2011). Second, at a higher level of economic complexity, the increasing use of machines and robots may lead to the depletion of obsolete jobs among low- and medium-skilled workers, especially those associated with routine activities (Raquel and Biagi 2018). Nevertheless, demand for high-skilled labor who could be in charge of “cognitive” tasks and ensure success rate of the new product development is always in an upward trend (Autor and Salomons 2018, Violante 2008, Meschi and Vivarelli 2009). At the same time, there is also a shift from middle-income manufacturing to low-income service jobs where the possibility of machine substitution is low (Autor and Dorn 2013). The progress of economic complexity with its “deindustrialization” effect, therefore, increases income inequality. Additionally, given diverse and unique productive knowledge, a highly complex economy more likely specializes in sophisticated products. Meanwhile, the supply from natural resource-dependent sectors (hence, labor-intensive) and those that require low-skilled knowledge is replaced by imports (Anderson 2005, Meschi and Vivarelli 2009). As a result, the low-skilled labor is further left at a disadvantage where many of them neither retain current jobs nor acquire sufficient knowledge and skills to adapt to more demanding requirements from the labor market. This further enhances income inequality (Berman et al. 1998, Card and DiNardo 2002, Violante 2008). The positive relationship between economic complexity and income inequality could be witnessed through the consequences of economic transformation during the 1980s in the United State (Card and DiNardo 2002, Levy and Murnane 1992) or empirical cross-country evidence provided by Lee and Vu (2020), Chu and Hoang (2020), and Lee and Wang (2021).
Due to the existence of both positive and negative forces in the economic complexity-income inequality nexus, the non-linear relationship between the two factors is examined in some studies. Given that economic complexity could influence the level of income, the theoretical underpinnings for this non-linearity could be drawn from Kuznets (1955) who proposes an inverted U-shape (also known as the Kutznet curve) demonstrating the changes of income inequality by income. At the early phase of economic development, the economic rewards are likely to hold by sub-groups of the society, causing a wide income gap. The economic development in the latter phase allows the participation of more people from various social groups. This results in an improvement in the income distribution. Le et al. (2020) and Bandeira Morais et al. (2021) show empirical evidence to affirm that there exists a similar non-linear effect in the economic complexity-inequality nexus. Initially, the increase in the sophistication of an economy would raise more benefits for capital owners and skillful workers and hence, widening income disparity. However, as the productive structure becomes more diverse, at a certain threshold, the improvement of institutions, bargaining powers of workers, and occupational opportunities enabled by a highly complex economy would turn the effect of economic complexity on income inequality to negative. This constitutes an inverted U-shape relationship between the two factors. The existing literature has some limitations. First, upon the theoretical perspective, the empirical evidence of previous studies does not show the “deindustrialization” effect where the advanced technology in a highly complex economy causes the destruction of manufacturing employment among low- and medium workers, and hence, raise income inequality again. Second, regarding the measurement method, Le et al. (2020) employ export diversification to proxy a nation’s productive structure. This indicator is deemed to be less comprehensive than economic complexity index, as proposed by Hidalgo and Hausmann (2009). Third, about data, Bandeira Morais et al. (2021) only show the empirical evidence for Brazil states only. This study, therefore, revisits the nonlinear analysis of the economic complexity-inequality linkage while compensating for the limitations of previous works.
H1: Economic complexity has a non-linear relationship with income inequality
2.2. Shadow economy and income inequality
As an inevitable part of the official economy, the shadow economy also plays an important role in the distribution of economic rewards (Alm and Embaye 2013, Bajada and Schneider 2005). On the one hand, the shadow economy mostly has a relatively small-scale operation, which is characterized by a higher labor-intensive yet lower capital-intensive production model, as compared to the formal sector. Therefore, the shadow economy mostly attracts the employment of low-skilled and unskilled labor and hence, becomes a survival source of income for the poor, as mentioned in the residue theory (Bajada and Schneider 2009, Hatipoglu and Ozbek 2011, Sethuraman 1976). In this regard, participating in underground market-based activities could be considered as an important option for the poor to be salvaged from poverty (Kim 2005). Along with the process of urbanization, the shadow economy attracts the poor from rural areas to conduct informal jobs in urban areas for higher wages (Bhattacharya 2011). The demand for low-skilled workers for underground activities is relatively stable as informal firms deliberately keep their business operations at a small scale to avoid detection from the government (Eilat and Zinnes 2002). Moreover, the unofficial sectors also function as salvage for low-skilled employees once they lose official work (Eilat and Zinnes 2002, Dell’Anno and Solomon 2008). The shadow economy, therefore, not only creates jobs and income but also ensures overall employment and reduces the likelihood of income loss among the poor (Bhattacharya 2011, Okumu 2014). This helps reduce income inequality in the long run.
Moreover, given that informal business (mostly include the poor and small firms) generates better income for those at the bottom end of the income spectrum, the development and power of these firms may indirectly narrow the income gap. From the legalism and voluntarism perspectives, the growth of the shadow economy intensifies the unfair competition between formal and informal businesses (Chen 2012). Since the informal sectors are excluded from the government’s regulations (such as the imposition of tax and fee), they may have certain advantages to capture higher economic rewards that would be distributed among those of the marginal society. In addition, due to lower entry costs and higher flexibility, the shadow economy attracts new start-ups, which mostly lack access to formal finance to test and grow their business (Williams 2006). The emergence of new ventures, in turn, helps create more job opportunities for low-skilled and unskilled labor. Especially, in a country with high corruption and misplaced institutions, the shadow economy could substitute the “invisible hand” to function as an outlet for the vulnerable segment of the business community in fostering entrepreneurship, creating new markets, intensifying competition, and accessing economic resources that they may not attain in normal conditions. Correspondingly, the poor and small firms could be empowered to receive better shares of economic returns (Asea 1996, Schneider and Enste 2000, Shleifer and Vishny 1998). This, in turn, create positive changes in income distribution.
As the shadow economy grows and accounts for a higher share in the economy, its positive effects in raising income for the poor and facilitating the growth of new ventures and small firms will be stronger. We, therefore, name this channel as “scale effect” that is affirmed in some previous works such as Valentini (2009), Bhattacharya (2011), Okumu (2014), and Huynh and Nguyen (2020).
On the other hand, the shadow economy may widen income gap because of several reasons. First, the exclusion of market-based transactions from official accounts creates obstacles for the government in collecting taxes. The loss of tax revenue hinders the sufficient provision of public goods and services under redistributive policies (Gërxhani 2004, Rosser et al. 2000, 2003, Schneider and Enste 2000). The poor and the low-productivity people would suffer the most from this loss, especially during economic shocks when their survival depends largely on subsidies. In this regard, the growth of the shadow economy may worsen income inequality (Ahmed et al. 2007, Rosser et al. 2000).
Second, competition is the major force of efficiency in resource allocation under a market economy (Scherer 1979). The growth of a shadow economy that breaks the “rules of the game” could reduce competition (Eilat and Zinnes 2002). Specifically, a large share of the shadow economy not only signals the poor institutional quality with the high tax burden, corruption, and bureaucratic issues but also implies the threat from “unfair” competition against informal firms. This would discourage the market entry of new investors, especially foreign ones which mostly want to operate in the formal sectors for better visibility and protection under laws (Cuong 2020, Huynh et al. 2019, Lambsdorff 2003). Another line of research contends that the existence of a larger shadow economy indicates “unofficial” opportunities for either bribery or tax evasion (Chiarini et al. 2013, Egger and Winner 2005) and therefore, may attract more greenfield investments (Ali and Bohara 2017, Cuong 2020). However, the existence of too many underground activities would, in turn, make it costly for the government to implement necessary regulations and policies aiming at maintaining healthy competition and preventing monopolistic practices (Eilat and Zinnes 2002). Consequently, the government would rather ignore it or reap benefits through corruption. This further destroys healthy market competition and leads to higher prices that would further benefit the equity owners and hence, widen income gap.
Third, the rise in labor supply for unofficial economic activities may widen income gap (Binelli and Attanasio 2010, Binelli 2016). This could be explained by the flexibility of wage policies in the shadow economy. While wages are well regulated in the official economy, the shadow participants are not protected by laws or legal commitments for their earnings (Krstić and Sanfey 2007, 2011, Xue et al. 2014). As the shadow economy grows, especially in low-wage sectors, the income inequality within the shadow economy itself and between the formal and informal sectors may increase (Dell’Anno and Solomon 2014, Xue et al. 2014).
Fourth, hiding in the shadow economy undermines the growth of informal firms and hence, further increase the income gap between the shadow and non-shadow sectors. Since the small-scale production makes it easier for firms to hide from the government, the shadow economy is mostly dominated by small-sized firms, which hardly have intensives to expand. Moreover, even when they aspirate for better growth, their lack of access to formal finance and necessary public goods and services limits their innovation and expansion (Straub 2005). As a result, the informal firms are characterized by low productivity and low returns, hence, could not ensure the improvement of income among their employees, including mostly the poor and low-skilled labor.
Fifth, the literature also documents the participation of large-sized firms in the shadow economy (Boycko et al. 1995, Kaminski 1996). However, different from smaller firms that operate unofficially for survival, these large firms aim at tax evasion by declaring less than actual production outputs or avoiding regulations that are deemed to be unfavorable to their profitability. This further benefits the high-income individuals who own or work for large-sized companies, and hence, worsen income inequality (Pashardes and Polycarpou 2008).
The positive impacts of the shadow economy and income inequality are empirically affirmed in some research such as Chong and Grandstein (2007), Pashardes and Polycarpou (2008), Krstić and Sanfey (2007, 2011), Xue et al. (2014), and Berdiev et al. (2018). The arguments of these studies are commonly rooted in the deregulation of the shadow economy. Given that ensuring social equality is primarily embedded in the functions of most governments’ regulations and policies, the shadow economy that deliberately conceals underground activities from public authorities could widen the income gap. We, therefore, name this channel as the “deregulation effect”. The scale effect and the deregulation effect of the shadow economy would occur at the same time. Their strength depends on the size of the informal sectors in an economy. Since these effects could influence income inequality in opposite directions, there may be a change in the relative strength of one against the other by the degree of informality. This would form a non-linear relationship between shadow economy and income inequality. Yap et al. (2019) find an inverted N-shaped relationship between the shadow economy and income inequality using panel data of 154 developed and developing countries between 2000 and 2007. Within the threshold from 18 to 65, a larger size of the shadow economy could help reduce income inequality. Meanwhile, a positive impact of the underground economy on income disparity is found outside this range.
H2: Shadow economy has a non-linear relationship with income inequality