Scholars and policymakers, including international organisations, cannot overemphasise the role of labour productivity growth in economic development. The structural change literature argues that economy-wide productivity can be improved within existing economies activities through capital accumulation or technological change (within effect) and through the reallocation of labour from less productive to high productive activities (dynamic or structural change effect) (McMillan & Rodrik, 2011; Diao, McMillan, & Rodrik, 2017). More importantly, the literature suggests that partial analyses of productivity performance within individual sectors (e.g., manufacturing) can be misleading when there are significant differences in labour productivities across economic activities (McMillan & Rodrik, 2011; Diao et al., 2017).
It is well established from various studies that labour productivity disparities between sectors are common in developing countries and prominently in Africa. For example, McMillan and Rodrik (2011) highlight in their study the differences in average productivity between agricultural and non-agriculture sectors, discovering that labour productivity in the mining sector in Malawi is 136 times larger than in agriculture. Similar studies that pointed out the sectoral gaps in cross-country studies include Diao et al. (2017), Mensah et al. (2018) and Diao et al. (2021). The findings suggest that mining is the sector with one of the highest productivity levels on average, while agriculture remains the lowest. Despite the significant gaps between the sectors, a recent study by Diao et al. (2021) highlights the disappointing labour productivity growth within non-agricultural industries and, in particular, manufacturing and services in Sub-Saharan African (SSA) countries.
Although, labour productivity has been subject to many studies from different dimensions – macroeconomic, sectoral, and firm-level – and other perspectives such as the neoclassical growth[1] literature and the fundamental determinant[2] of differences in economic growth literature, the findings remain mixed and inconclusive. According to Dieppe (2021), a possible explanation includes the changing role of conventional factors and the structural changes that developing economies have undergone during the last decades. Another explanation is the growing literature on the New Structural Economics (NSE), which argues that economic outcomes are endogenous to a country's development strategies[3] and endowment structure and many developing countries failed to industrialise because of their approach to capital-intensive industries, which were not favourable to the endowment structures of their economies (Lin, 2003).
Despite the theoretical and empirical evidence of the NSE, relevant studies are limited to macroeconomic outcomes, and little is known about the effect of development strategy on the sectoral contribution of aggregate growth using sector-level data. To the best of my knowledge, only the study from Gnangnon (2020) assessing the effect of comparative development strategy and Aid for Trade on structural change in production, and the study from Diao et al. (2021) are closely related to this paper. However, the study from Gnangnon (2020) uses two indexes as a measure of structural change in production – the Norm and Absolute Value Index and the Modified Lilien Index of structural change – and not the structural change component derived from the decomposition of growth using a shift and share analysis method, accounting for the reallocation of labour and the value added by sector. He finds that more prominent levels of Aid for Trade flows help foster structural change in production in countries that have embraced a comparative advantage development strategy.
Another study is that of Diao et al. (2021). They investigate the productivity growth in agriculture despite the declining employment and the declining productivity growth in manufacturing in Tanzania and Ethiopia. They find that large firms are more productive with fewer employment opportunities. In contrast, small firms are less productive but absorb more employment. An additional examination of this contrast by comparing the capital-labour ratio of firms in Tanzania and Ethiopia reveals that large firms' capital-labour ratio in Tanzania and Ethiopia's manufacturing sectors is equivalent to that in considerably richer OECD countries. It has risen faster in Tanzanian and Ethiopian manufacturing than in the economy as a whole. However, this study is mainly restricted to a comparative analysis of the capital-labour ratio of manufacturing firms between Tanzania, Ethiopia, and the Czech Republic.
Against this backdrop, the paper contributes to the existing literature in the following ways. In the first part of this paper, I identify the sectoral contributions to aggregate labour productivity growth in twenty-one Sub-Sahara African (SSA) countries over the 1960–2017 period. More specifically, I decompose the aggregate productivity growth into its main components and explore the role played by each component in contributing to growth in the long-term and also during each significant economic development period of SSA countries. The focus on analysing productivity growth is consistent with the global interest in improving labour productivity growth. Based on the shift-share decomposition analysis results, in the second part, I combine an econometric model to analyse the effect of comparative advantage development strategy on growth components. More specifically, I investigate the role of the Technology Choice Index (TCI) – a proxy for comparative advantage development strategy – on within effects, Static effects and dynamic effects.
The rest of the paper is organised as follows. The following section provides existing evidence on the role of growth components. It discusses the related literature on the NSEs and the link between TCI and macroeconomic outcomes. Section 3 describes the empirical strategy and data. Section 4 presents and discusses the results, and section 5 concludes the paper.
[1] Studies related to the impact of neoclassical growth model factors include but are not limited to (Belorgey, Lecat, & Maury, 2006); (Supachet, 2010); and (Najarzadeh, Rahimzadeh, & Reed, 2014).
[2] Some examples of studies on the fundamental determinant of growth literature, see: (Bloch & Tang, 2004); (Rodrik, 2003); (Acemoglu, 2009); (Acemogl et al., 2002; 2003)
[3] Development strategy in this context refers to industrial policy and other strategies toward industrialisation. This will be used interchangeably during the study.