Structural models and structural change: analytical principles and methodological issues

Structural analysis is the main topic of this paper and structural change is a dominant theme of the present work. The analysis of structural models and of theories of structural changes carried out in this paper has a double meaning. On the one hand, it allows to pick up several essential principles that characterize these models, on the other hand, it should allow us to reconsider some important methodological issues under a new light, such as different methods of decomposition of the productive systems, the problem of complexity and the strategies to reduce complexity. Moreover, the paper tries to compare Quesnay’s Tableau, taken as a benchmark model, with Leontief’s, von Neumann’s and Sraffa’s models to pick up the different features of these models with respect to his theoretical framework and also to identify their characteristics for structural analysis and structural change.

Wassily Leontief and Léon Walras: the Production as a Circular Flow

Leontief’s input-output models are usually viewed as simplified classical (neo-Ricardian) models. However, this interpretation hides two opposed views. On the one hand, the common interpretation, based on Koopmans and Samuelson’s works, considers the so-called “models of Leontief” as simplified Ricardian models, in the sense of Samuelson, which are shown to be special cases of general equilibrium theory. In their framework, general equilibrium theory might be interpreted as a generalized model of Leontief and, reversely, models of Leontief are simplified Walrasian general equilibrium models. According to this theoretical tradition, classical theory and Walrasian general equilibrium theory are intimately linked and Classical economics is an “archaic” general equilibrium theory. On the other hand, neo-Ricardians view models of Leontief as simplified classical models that are incompatible with Walras’ general equilibrium theory. Our paper examines in details the last argument: the incompatibility argument. Such a work will require to examine in details the definition of vague categories as "Walrasian", "Classical" and so forth. We show that incompatibility between models of Leontief and Walras’ general equilibrium theory is ultimately based on Sraffa’s worldview: “The connection of [my] work with the theories of the old classical economists has been alluded to in the preface... It is of course in Quesnay’s Tableau Economique that is found the original picture of the system of production and consumption as a circular process, and it stands in striking contrast to the view presented by modern theory of a one-way avenue that leads from ‘Factors of production’ to ‘Consumption goods’.” (Sraffa, 1960) Neo-Ricardian’s opposition between classical economics and Walrasian theory is based on the representation of production: classical economics refers to circular flow while Marginalist theory refers to a one-way avenue production process. As it makes a sharp distinction between the two theoretical traditions, we call this criterion "Sraffa’s Guillotine". Based on Leontief’s PhD dissertation (1928) and his early input-output model (1937), the main result of our inquiry is that this criterion is powerless to distinguish Leontief’s representation of production as a circular flow and Walras one. Indeed, while Leontief based his models on Marx’ reproduction scheme, his representation of production is the same than Walras’ complete one, in striking contrast with neo-Ricardian critical apparatus. Hence we argue in favor of a pluralist interpretation of the models of Leontief: both Classical and Walrasians.Walras, Sraffa, Leontief, input-output analysis, Marx, production, non substitution theorem, general equilibrium theory

Nash Social Welfare Approximation for Strategic Agents

The fair division of resources is an important age-old problem that has led to a rich body of literature. At the center of this literature lies the question of whether there exist fair mechanisms despite strategic behavior of the agents. A fundamental objective function used for measuring fair outcomes is the Nash social welfare, defined as the geometric mean of the agent utilities. This objective function is maximized by widely known solution concepts such as Nash bargaining and the competitive equilibrium with equal incomes. In this work we focus on the question of (approximately) implementing the Nash social welfare. The starting point of our analysis is the Fisher market, a fundamental model of an economy, whose benchmark is precisely the (weighted) Nash social welfare. We begin by studying two extreme classes of valuations functions, namely perfect substitutes and perfect complements, and find that for perfect substitutes, the Fisher market mechanism has a constant approximation: at most 2 and at least e1e. However, for perfect complements, the Fisher market does not work well, its bound degrading linearly with the number of players. Strikingly, the Trading Post mechanism---an indirect market mechanism also known as the Shapley-Shubik game---has significantly better performance than the Fisher market on its own benchmark. Not only does Trading Post achieve an approximation of 2 for perfect substitutes, but this bound holds for all concave utilities and becomes arbitrarily close to optimal for Leontief utilities (perfect complements), where it reaches $(1+\epsilon)$ for every $\epsilon > 0$. Moreover, all the Nash equilibria of the Trading Post mechanism are pure for all concave utilities and satisfy an important notion of fairness known as proportionality

Input-Output in Europe: Trends in Research and Application

Indubitably born in the USA, input-output analysis has an important European history, from its very beginnings in the Soviet Union to the postwar huge development of I/O techniques in West and North Europe. This paper studies the European experience of input-output analysis by surveying and analyzing some of the national experiences and especially the works in Great Britain of Richard Stone and his team. We show in particular how European economists have taken leadership in I/O research since the 1950s and more recently with the creation in 1989 of the journal of the International Input-Output Association, Economic System Research. In the latter European influence tends to focus works on theoretical and methodological issues more than empirical issues and applicationsInput-Output Analysis, Leontief, Stone, Applied economics, SAM, Computable General Equilibriun Models

A Computable General Equilibrium Analysis of the Relative Price Sensitivity Required to Induce Rebound Effects in Response to an Improvement in Energy Efficiency in the UK Economy

In recent years there has been extensive debate in the energy economics and policy literature on the likely impacts of improvements in energy efficiency. This debate has focussed on the notion of rebound effects. Rebound effects occur when improvements in energy efficiency actually stimulate the direct and indirect demand for energy in production and/or consumption. This phenomenon occurs through the impact of the increased efficiency on the effective, or implicit, price of energy. If demand is stimulated in this way, the anticipated reduction in energy use, and the consequent environmental benefits, will be partially or possibly even more than wholly (in the case of ‘backfire’ effects) offset. A recent report published by the UK House of Lords identifies rebound effects as a plausible explanation as to why recent improvements in energy efficiency in the UK have not translated to reductions in energy demand at the macroeconomic level, but calls for empirical investigation of the factors that govern the extent of such effects.Undoubtedly the single most important conclusion of recent analysis in the UK, led by the UK Energy Research Centre (UKERC) is that the extent of rebound and backfire effects is always and everywhere an empirical issue. It is simply not possible to determine the degree of rebound and backfire from theoretical considerations alone, notwithstanding the claims of some contributors to the debate. In particular, theoretical analysis cannot rule out backfire. Nor, strictly, can theoretical considerations alone rule out the other limiting case, of zero rebound, that a narrow engineering approach would imply. In this paper we use a computable general equilibrium (CGE) framework to investigate the conditions under which rebound effects may occur in the Scottish regional and UK national economies. Previous work has suggested that rebound effects will occur even where key elasticities of substitution in production are set close to zero. Here, we carry out a systematic sensitivity analysis, where we gradually introduce relative price sensitivity into the system, focusing in particular on elasticities of substitution in production and trade parameters, in order to determine conditions under which rebound effects become a likely outcome. We find that, while there is positive pressure for rebound effects even where (direct and indirect) demand for energy is very price inelastic, this may be partially or wholly offset by negative income and disinvestment effects, which also occur in response to falling energy prices.CGE modelling, energy efficiency, rebound effects

Sraffa's Prices

First we consider the existence question in Sraffa’s Chapter I dismissed by counting equations and unknowns. A theorem from the theory of Markov processes, applied to distributions not now of probability but of goods to sectors, shows the general existence of non-negative prices satisfying the conditions imposed by the value equation, that value of output equals value of input. The further condition for these to be unique and positive is that the economy be irreducible, or that no independent sub-economy should exist. Sraffa provides a precise formula determining unique prices, he barely escapes imposing too many conditions on them and certainly cannot require more. In the background and giving motive to the enquiry is the Labour Theory of Value, that goes further. It asserts that the value of anything is ultimately equal to the labour that has gone into making it; so it implies the same principle expressed by the value equation, but a further condition has been added about the nature of the unit. Since the value equation alone makes prices fully determined, there is no room for further conditions, so there is an obstacle to the application of the theory. Standing as a canonical text in a revival of interest in the Theory Of Value serving earlier thought and the later concentration of Ricardo, it offers an exercise in labour value arithmetic, where the only fruit is to find the arithmetic is impossible. An extended interdependence, which applies to repeated production, appears as a stability condition for prices in an adjustment process, and so does the existence of what Sraffa calls a standard commodity, one depending on all others for its production. After treating a case where there is a surplus, and joint production, the relation with Leontief and von Neumann is considered.Schools of Economic Thought and Methodology, Current Heterodox Approaches, Socialist, Marxian, Sraffian