Historical models and economic syllogisms

This paper proposes a classification of economic models into three types: historical, axiomatic and conditional. Historical or empirical models utilize the historical-deductive method, and are generalizations from the economic regularities and tendencies that we find in the real world. Axiomatic models utilize the hypothetical-deductive method; they are syllogisms whose major premise is an axiom – a self-evident truth; they are appropriate for methodological sciences such as mathematics and econometrics. Conditional economic models are likewise syllogisms, but they are suitable for economics because they make for clearer and more precise economic reasoning. The criterion of truth of the substantive sciences is the conformity with reality, of the methodological science, its internal consistency. When a school of economic thought adopts mainly axiomatic models, as is the case with neoclassical economics, it implicitly falls into contradiction because their best representatives believe in the conformity with reality criterion.     

Optimal monetary policy and economic growth

A question at the center of many analyses of optimal monetary policy is, why do central banks never implement the Friedman rule? To the list of answers to this question, we add neoclassical production (specifically, the Tobin effect) as one possible explanation. To that end, we study an overlapping generations economy with capital where limited communication and stochastic relocation create an endogenous transactions role for fiat money. We assume a production function with a knowledge externality (Romer style) that nests economies with endogenous growth (AK form) and those with no long-run growth (the Diamond model). The Tobin effect is shown to be always operative. Under CRRA preferences, a mild degree of social increasing returns is sufficient (but not necessary) for some positive inflation to dominate zero inflation and for the Friedman rule to be sub-optimal, irrespective of the degree of risk aversion.     

Endogenicity of economic growth models

In his celebrated 1956 article, “A Contribution to the Theory of Economic Growth,” Solow calibrated the stylized facts of economic growth observed in the Western developed countries and summed up by Kaldor. Solow reconciled steady-state rate of growth of per capita output with constant capital/output and capital/labor ratios by introducing labor augmenting technological progress and measuring physical labor time in efficiency units. A series of articles have appeared since the mid-1980s, which have substantially extended the neoclassical model of growth theory presented by Solow. Most of these are entitled endogenous in juxtaposition to Solow's model, which is considered and often labeled exogenous. The purpose of this article is to show that this dichotomy is not worthwhile by arguing that the way technological progress enters in Solow's model plays a crucial role. Moreover, the designation of a model need not depend on the way it employs just one element among others.     

Access to transportation,residential segregation,and economic opportunity

The Housing Choice Voucher Program assists low-income families to afford decent housing and provide them with better economic opportunities. There is growing evidence that public transportation plays an important role in shaping the residential location choices of low-income households. However, transportation has not been a major focus of the research related to housing voucher programs. We develop a general equilibrium model of a city with multiple districts, decentralized employment, multiple commuting modes, and locally financed education. We compare housing vouchers with transportation vouchers with respect to poverty deconcentration, educational quality in each district, unskilled employment in the suburbs, and welfare.     

Automating the computation of solutions of large economic models

The computer implementation of any large economic model is usually a very expensive and time consuming task. This paper describes a software package, called GEMPACK, which is being developed specifically to reduce dramatically the research time, effort and cost required to set up one solution method (the Johansen method) on an actual computer. Existing features of GEMPACK are described in detail, as are developments planned for the near future. The software is model-independent, in that it works for a wide class of economic models, irrespective of the form of the equations or underlying theory. GEMPACK is portable to most mini and mainframe computers, because it has been written in ANSI standard FORTRAN 77, with such portability as a primary requirement. Several models, including the Dervis, de Melo and Robinson model of Korea, have been implemented using GEMPACK.     

Linking dynamic economic and ecological general equilibrium models

Although ecosystems provide myriad services to economies, only one service is considered in most renewable-resource models. The general equilibrium bioeconomic model introduced here admits a second service, and more importantly it accounts for how the two services are impacted by interactions within an eight-species ecosystem and interactions within a regional economy. Endangered Steller sea lion recovery measures via alternative pollock quotas change all ecosystem populations and all economic variables. While non-use values associated with the ecosystem (e.g., existence values) are not considered, all species matter for the economy because they are all used indirectly as support for ecosystem services. Regional welfare changes from reduced quotas show the tradeoff between consumptive and non-consumptive uses of the ecosystem.     

Pure exchange equilibrium of dynamic economic models

This paper studies competitive equilibrium over time of a one good model in which the agents are members of a population which grows at a constant rate. Each agent lives for n periods and in the i-th period of his life receives an endowment of e_i units of goods. Goods can neither be produced nor stored. The model is thus the n-period generalization of the two- and three-period models studied by Samuelson in [4]. We seek to ascertain the structure of the time paths of consumption in these models. Our results can be summarized roughly as follows: In general, there will exist two kinds of steady state paths, (i) golden rule paths in which the rate of interest equals the growth rate of population and (ii) “balanced” paths in which the aggregate assets or indebtedness of the society as a whole is zero (a fundamental fact about dynamic models is that it is possible for aggregate debt not to equal aggregate credit as it must in the static case). A model is termed classical if in the golden rule state aggregate assets are negative (or debt positive) and Samuelson (following [4]) in the opposite case. It is conjectured that the golden rule program is globally stable in the classical case and the balanced program is stable in the Samuelson case. This is established for the special case n = 2.     

Optimal transmission switching: economic efficiency and market implications

Traditionally, transmission assets for bulk power flow in the electric grid have been modeled as fixed assets in the short run, except during times of forced outages or maintenance. This traditional view does not permit reconfiguration of the transmission grid by the system operators to improve system performance and economic efficiency. The current push to create a smarter grid has brought to the forefront the possibility of co-optimizing generation along with the network topology by incorporating the control of transmission assets within the economic dispatch formulations. Unfortunately, even though such co-optimization improves the social welfare, it may be incompatible with prevailing market design practices since it can create winners and losers among market participants and it has unpredictable distributional consequences in the energy market and in the financial transmission rights (FTR) market. In this paper, we first provide an overview of recent research on optimal transmission switching, which demonstrates the substantial economic benefit that is possible even while satisfying standard N−1 reliability requirements. We then discuss various market implications resulting from co-optimizing the network topology with generation and we examine how transmission switching may affect locational Marginal Prices (LMPs), i.e., energy prices, and revenue adequacy in the FTR market when FTR settlements are financed by congestion revenues.     

Psychological versus economic models of bounded rationality

That the rationality of individual people is ‘bounded’ – that is, finite in scope and representational reach, and constrained by the opportunity cost of time – cannot reasonably be controversial as an empirical matter. In this context, the paper addresses the question as to why, if economics is an empirical science, economists introduce bounds on the rationality of agents in their models only grudgingly and partially. The answer defended in the paper is that most economists are interested primarily in markets and only secondarily in the dynamics of individual decisions – specifically, they are interested in these dynamics mainly insofar as they might systematically influence the most useful approaches to modeling interesting markets. In market contexts, bounds on rationality are typically generated by institutional and informational properties specific to the market in question, which arise and are sustained by structural dynamics that do not originate in or reduce to individuals' decisions or psychological dispositions. To be sure, these influences interact with psychological dispositions, so economists have reason to attend to the psychology of valuation. But no general model of bounded rationality should ever be expected to feature in the economist's toolkit, regardless of the extent to which psychologists successfully identify specific human cognitive limitations. Use of moderate rational expectations assumptions should be understood in this light. Such assumptions are readily relaxed in specific applications, and in ways customized to modeling circumstances, that modelers, experimentalists, and econometricians are making steadily more sophisticated.     

Clubs,local public goods and transportation models: A synthesis

Clubs, local public goods, and transportation models are analyzed within a unified model. The emphasis is on the derivation of optimal allocation, pricing and the size of the sharing group. We derive the conditions under which optimal prices will yield surplus or deficit, as well as those under which competitive provision will be efficient. Given heterogeneous tastes we prove that segregation according to tastes is generally efficient although several cases where this result does not hold are also discussed. We show that the existing literature is unnecessarily restrictive and that the unified approach suggested here considerably extends the existing analysis of clubs' local public goods and the transportation problems.     

A note on the triple difference in economic models

This article shows when a triple difference strategy using an imperfect control category improves on the double difference strategy for estimating an average treatment effect. For example, a product is treated in one place and not another leading to a double difference strategy. When does comparison with an untreated product in triple difference strategy improve accuracy?     

Optimal taxation,the compensation principle and the measurement of changes in economic welfare

This paper explores the implications of optimal taxation for the measurement of changes in economic welfare. It shows that the measure implied by the compensation principle — the sum of the relevant compensating variations — is only accurate in the presence of optimal lump-sum taxation: an unsurprising conclusion, but a gloomy one given that such taxation is generally infeasible. However, all is not lost. The paper uses the linear income tax case to show that it is possible to derive weights that can be attached to the relevant compensating variations to provide accurate measures of changes in welfare in the presence of second-best taxation: weights that can be calculated from observable data.     

On some criteria for the formulation and testing of economic growth models

This paper presents a methodology for the formulation and testing of economic growth models. The model selected includes two production sectors with physical and human capital accumulation. These capital stocks are associated with spillover effects in the production of the physical good and in the accumulation of both factors.     

Optimal growth and cycles in overlapping generations models

Summary This paper investigates the dynamical properties of optimal paths in one-sector overlapping generations models without assuming that the utility function of the representative agent is separable. When the utility function is separable, the optimal growth paths monotonically converges toward the modified golden rule steady state. In the non-separable case, we show that the optimal growth path may be oscillating and optimal two-period cycles may exist. Applying these results to the model with altruism, we show that the condition of operative bequest is fully compatible with endogeneous fluctuations provided that the discount factor is close enough to one. All our results are illustrated using Cobb-Douglas utility and production functions.We thank C. Blackorby, J. Blot, P. Cartigny and one anonymous referee for helpful comments and suggestions which generally improved the exposition of the paper. We would also like to thank the participants of the Population and demography session of the European Economic Association 10th Annual Congress (Prague, The Czech Republic, September 1–4, 1995).     

Market structure and competitive equilibrium in dynamic economic models

Recently theorists have analyzed economies which potentially contain both finite and infinite horizon overlapping generations, using “Arrow-Debreu” (complete) markets. Typically, applied models assume recursive spot and contingent securities markets, implying a different equilibrium concept. Indeed, if infinite horizon agents are present recursive equilibria cannot exist without some side conditions on debt. With the right side conditions, we show that every recursive market equilibrium allocation is a complete market equilibrium allocation and vice versa. This bridges a gap between theory and applications, and extends existing equivalence results on market structure.     

Scale effects in Schumpeterian models of economic growth

Early models of Schumpeterian growth incorporate scale effects predicting that large economies grow faster than small economies, and that population growth causes accelerating per capita income growth. An absence of clear empirical evidence for these scale effects has led some researchers to question the foundations underlying the Schumpeterian approach to growth. This paper reviews empirical evidence on the relationship between scale and growth, and recent attempts to construct Schumpeterian growth models without scale effects.     

Non-causal understanding with economic models: the case of general equilibrium

How can we use models to understand real phenomena if models misrepresent the very phenomena we seek to understand? Some accounts suggest that models may afford understanding by providing causal knowledge about phenomena via how-possibly explanations. However, general equilibrium models, for example, pose a challenge to this solution since their contribution appears to be purely mathematical results. Despite this, practitioners widely acknowledge that it improves our understanding of the world. I argue that the Arrow–Debreu model provides a mathematical how-possibly explanation which establishes claims of mathematical dependence. The account developed reveals how mathematical knowledge can inform claims about the world, allow ‘what-if-things-had-been-different’ inferences, and thus improve our understanding.