مجموع علیت در یک رویکرد پویای اقتصادی ساختاری برای رشد و توسعه اقتصادی نابرابر

A structural economic dynamic approach is distinguishable by its simultaneous considerations of supply and demand and their related effects wielded upon economic growth. However, properly considering cumulative causation requires a special framework for more fully accounting for technological progress, and not leaving it as simply exogenous. With this inquiry dimensions of Verdoorn's Law are selectively embedded in Pasinetti's multi-sector model, thus allowing us to better consider cumulative causation through rendering structural changes endogenous. In this setup, reconciliation between cumulative causation and balance of payments constrained views is shown to hold.

“Where does technical progress come from? What is its source? How are economic systems induced to take advantage of it? And why is it that some countries took advantage of it earlier than others? Why are most countries still so far behind? By which factors have they been blocked? And again, how is it that some countries, after lagging behind, have then caught up so quickly and are now themselves among the leaders? Will it be possible for other countries do to the same? How? These and similar questions are really fascinating. They are precisely the type of questions that have constantly struck and puzzled the imagination of the most perceptive minds among economists.” L. Pasinetti (1993, p. 106): Structural Economic Dynamics: A Theory of the Economic Consequences of Human Learning. Although cumulative causation and structural change register as concepts alien to most of mainstream economics, these stand as important terms and also central tenets of Post-Keynesian growth theory, playing crucial roles for explaining contemporaneous processes taking place integral to economic development. See, for example, contributions of Ocampo (2005), Cornwall and Cornwall (2002) and Setterfield (1997). The concept of cumulative causation has been addressed by a number of authors such as Kaldor, 1966 and Kaldor, 1972,1Skott (1988), and McCombie and Thirlwall (1994), to describe one of the logical effects of static and dynamic economies of scale, or what could be thought of as increasing returns considered in its widest sense. According to this view, manufacturing is thought to play special roles in generating dynamics that can run throughout a macro economy. Especially when considering backward and forward linkages and economies of scale, cumulative causation helps us explain why a faster growth of output leads to faster growth rates of productivity: thus rendering economic growth demand induced rather than resource constrained. Structural change should be seen as intrinsically related to processes of cumulative causation, and was formally studied among others2 by Pasinetti, 1981 and Pasinetti, 1993 and presented as integral to his structural economic dynamic (SED) approach. According to Pasinetti, structural change refers to variations in the structure of an economy, and should be understood as related to the existence of particular rates of technological progress and also demand levels for final consumption goods. His emphasis upon demand composition offers a significant qualitative improvement vis-a-vis traditional, aggregated models3 that fail to adequately consider composition of consumption demand. The importance of this issue in the study of economic development has been considered. Authors such as Ocampo (2005, p. 8) and Rodrik (2008, p. 398) consider that success in structural change proves key to understanding processes integral to economic development. Although the Pasinettian approach offers some clear advantages over the aggregated approach, technological change is treated essentially in the same exogenous manner4 as in the mainstream view, however, with the advantage that each sector is assigned a particular rate of technological progress. Some attempts of giving a better treatment for technological progress in the Pasinettian framework were provided by a number of authors. Reati (1998), for example, introduced long waves for explaining technological revolutions, while also considering a complex dynamics for prices, output and employment. Araujo and Teixeira (2011) and D’Agata (2010) have also aimed at endogenizing technological progress in this framework, by considering an evolutionary view of dynamic capabilities as fundamental forces driving technological change. Although these approaches have proven useful we note a failure for dealing with – or even considering – cumulative causation. Such a failure results in a weakness to account for connections between productivity and output growth in the tradition emphasized by Roberts and Setterfield (2007). According to these authors there is indeed a conception of endogenous technological growth associated with Post-Keynesian growth theory – specifically, the Kaldorian tradition – according to which the rate of technological progress remains sensitively related to a growth rate of output. Then, we could move to a relation in which “growth depends on growth.” Adding a temporal dimension to the relationship, growth at any point in time depends on its own history in a self-reinforcing schema of cumulative causation. By ignoring cumulative causation, Pasinetti's SED approach overlooks some crucial dimensions of economic growth, calling his approach into question. In this vein, this inquiry seeks to enhance the Pasinettian multi-sector growth framework by endogenizing technological progress, and in such a way that the latter is made sensitive to developments from the demand-side of the economy5 – through the operation of Verdoorn's Law. Following this view, a deeper notion of technological progress is considered, thus making Pasinetti's analysis consistent with the deeper conception of endogenous growth identified by Roberts and Setterfield. The result is a multi-sector model of cumulative causation in which the pace of technological progress can indeed be determined.6 Worth noting is that some other authors have already sought to establish links between structural change and cumulative causation. Botta (2009), for example, stresses the importance of these linkages in a balance of payment constrained framework. In sum, industrialization and economic growth feedback to each other, giving rise to a cumulative causation process. Although Botta's approach focuses on connections between cumulative causation and structural change, it faces limitations when considering the latter for he relies upon an aggregated model. In addition, Fiorillo (2001) describes and simulates how rate of growth and specialization coevolve in an export-led growth model of Kaldorian-type. He focuses on feedback from growth rates to income elasticity of exports, accounting for the presence of endogenous changes in growth regimes. This means that a country specialization in a sector leads toward its maintaining its specialization unless the system reaches certain critical values. Fiorillo's result is confirmed herein from analytical and computational perspectives. Once a country establishes a comparative cost advantage in a specific sector, then, according to the cumulative causation viewpoint, it proves probable that advantage will indeed be maintained. This view is also according to Krugman (1987, pp. 46–47) who states that: “Basically, once a pattern of specialization is established, it remains unchanged, with changes in relative productivity acting to further lock the pattern in. (…) Like a river which digs its own bed deeper, a pattern of specialization, once established, will induce relative productivity changes which strengthen the forces preserving that pattern.” However, it could arise that a strategy of export-led growth – ELG hereafter – could indeed lead the laggard country to obtain access to economies with a higher per capita income that its own, allowing it to produce and export goods bearing a higher income elasticity of demand. Processes of ‘learning by doing’ that accrue from actual and ongoing production on a significant scale allow for the acquisition and assimilation of novel techniques of production that spur along productivity improvements. As a consequence there may take place structural changes that include the labor force migrating from low productivity to higher productivity sectors. The present analysis aims to join these lines of research on structural factors in a more fully specified multi-sectoral framework and by making this more inclusive demand side to interact with technological progress in an ELG model. Specifically, the present inquiry offers a vision of a canonical Post-Keynesian approach toward conceptualizing growth based upon principles of cumulative causation in which selected Post-Keynesian traditions,7 including Kaldorian and Pasinettian, are shown to be consistent. Following this line of reasoning, this inquiry also seeks to establish that in a SED approach reconciliation between cumulative causation and balance of payments (BOP) constrained views may be obtained.8 According to Thirlwall (1979), assuming that real exchange rates are constant and that trade must be balanced in the long run, there is a very close correspondence between the growth rate of output and the ratio of the growth of exports to the income elasticity of demand for imports. This result became known as Thirlwall's Law and Araujo and Lima (2007) have derived it in a multi-sectoral set up departing from the Pasinettian framework. They have shown that even in the case in which both the sectoral elasticities and the world growth rate are constant, changes in the growth rate of domestic output are possible due to changes in the share of each sector in aggregate exports or imports that accrue from the evolution of tastes and preferences according to Engel's law. Here it is shown that this result may be extended when cumulative causation is taken into account, making it possible to derive a multi-sectoral version of Thirlwall's Law that considers explicitly the influence of technological progress upon the growth rate of domestic output. In this vein the result obtained by Araujo and Lima (2007) is extended to highlight the influence of technological progress upon the BOP constrained growth rate. In this context changes in relative prices play important roles in the long run, thereby explaining relative cost competitiveness as this relates to endogenous technological progress, the explained force behind export successes. This inquiry, then, is structured as follows: in the next section technological progress is endogenized in Pasinetti's pure labor model by introducing sectoral versions of Verdoorn's law. Section 3 extends the multi-sectoral version of Thirlwall's Law so as to offer insights into uneven development. Section 4 summarizes the results.

In the present paper, by embedding cumulative causation in the Pasinettian analysis through Verdoorn's sectoral laws, technological progress was endogenized, and the role played by demand was evinced not only in structural changes, but also in the determination of the pace of technological progress. In this vein, a multi-sector model of cumulative causation was built and its implications over the process of economic development were considered. By following this approach we should also note that main channels of interactions between demand, technological progress and structural change were indeed taken into account. Besides, it was possible to extend the SED approach by including cumulative causation as one of the mechanisms explaining ever-widening per capita and technological gaps amongst rich and poor nations. The essence of the argument is that once a region gains a growth advantage its advantage will tend to be sustained through the process of increasing returns that growth itself induces – the Verdoorn effect. Besides, according to the view presented herein it was possible to combine Thirlwall's Law and Verdoorn's Law, which is evidence that there are benefits from combining insights from the various strands of Post-Keynesian growth theory. In this vein, cumulative causation still plays an important role even in the context of a BOP constrained growth. Following a SED approach embedded with cumulative causation it was emphasized that there is plenty of evidence that gains from international diffusion of technical progress are indeed conditioned to inherent patterns of human needs and preferences as these give rise to different compositions of consumer demand, patterns of technological progress and, therefore, different structures of production and employment in each country. Stated differently, the diffusion and absorption of technical progress are subject to different economic structures particular for developed and underdeveloped economies. A region that produces a final good with high income elasticity of demand will have high technological progress and thus exhibit faster growth rates, in general, than a region that produces a final good with small elasticity of demand. This result confirms what was reported by Thirlwall and Pacheco-López (2008, p. 69): “[t]hrough the ‘Verdoorn effect’, productivity growth will be higher and the economy will retain its competitive advantage in these goods, making it difficult, without protection or exceptional industrial enterprise, for other countries to establish the same commodities. In such a ‘cumulative’ model, it is the difference between the income elasticity characteristics of exports and imports which is the essence of divergence between industrial and agricultural economies (…)”.