能源投入产出模型的选择：混合型还是价值型*

将投入产出技术用于能源问题的分析时，当前文献中有两类模型：混合型能源投入产出模型和价值型能源投入产出模型，其中价值型模型应用更为广泛。本文从能源平衡方程入手，对这两类模型的本质特点和差异进行了辨析，通过严格证明，得到如下结论：第一，在技术系数矩阵稳定的条件下，出现新的最终需求时，混合型能源投入产出模型仍然保证能源平衡方程的成立，具备一致性。第二，在技术系数矩阵和能源价格矩阵稳定的条件下，出现新的最终需求时，价值型能源投入产出模型无法保证能源平衡方程的成立。虽然价值型能源投入产出模型在初始构建过程中使用了能源平衡方程，但本质上是以价值单位的投入产出方程为根本出发点的，并没有考虑能源平衡方程在新的最终需求发生时是否仍然成立的问题，没有考虑能源使用的一致性。因此，一般情况下混合型能源投入产出模 型更为合理。第三，在某些特殊情况下这两类模型等价：（1）当最终需求结构保持不变，而只有最终需求总量发生变化时；（2）当能源在各使用部门之间的价格完全相同时。这些结论为实际应用中如何选择恰当的能源投入产出模型提供了依据。     

On the median regression for SURE models with applications to 3-generation immigrants data in Sweden

In this paper we generalize the median regression method to be applicable to system of regression equations, in particular SURE models. Giving the existence of proper system wise medians of the residuals from different equations, we apply the weighted median regression with the weights obtained from the covariance matrix of the equations obtained from ordinary SURE method. The benefit of this model in our case is that the SURE estimators utilise the information present in the cross regression (or equations) error correlation and hence more efficient than other estimation methods like the OLS method. The Seemingly Unrelated Median Regression Equations (SUMRE) models produce results that are more robust than the usual SURE or single equations OLS estimation when the distributions of the dependent variables are not normally distributed or the data are associated with outliers. Moreover, the results are also more efficient than is the cases of single equations median regressions when the residuals from the different equations are correlated. A theorem is derived and indicates that even if there is no statistically significant correlation between the equations, using SUMRE model instead of SURE models will not damage the estimation of parameters.     

Analysis of the Lotka-Volterra competition equations as a technological substitution model

This paper provides insight into the dynamics of the Lotka-Volterra competition (LVC) equations, a much used competition model, and compares the dynamics of LVC competitive substitution to that of several well-known substitution models. The behavior of the LVC equations is analyzed for the special case of a dominant competitor at equilibrium being replaced after the introduction of a small population of an invading competitor with a competitive advantage. Expressions are derived that describe the growth of the invading competitor and that growth is shown to be of four classes: left asymmetric, logistic, right asymmetric with 1−ε₂ asymptote and right asymmetric with γ asymptote. It is shown that the LVC model reverts to logistic substitution in a market of fixed size, a result with important implications. The LVC equations are fitted to the Gompertz, Bass, Non-Symmetrical Responding Logistic (NSRL) and Sharif-Kabir substitution models and compared using a novel graphical technique. The LVC equations can reasonably mimic the full range of curve shapes exhibited by each of these models.     

Tariffs and Growth in the Late 19th Century

The paper estimates the correlation between tariffs and economic growth in the late 19th century, in the context of three types of growth equation: unconditional convergence equations; conditional convergence equations; and factor accumulation models. It does so for a panel of ten countries between 1875 and 1914. Tariffs were positively correlated with growth in these countries during this period.     

Dynamic specification and misspecification in systems of demand equations: a testing strategy for model selection

The purpose of this study is to describe a misspecification testing strategy that is designed to ensure the appropriateness of the statistical assumptions underlying a system of equations. A systemwise test approach is used to test the statistical assumptions. The systemwise tests take into account information in, and interaction between, all equations in the system and can be used in a wide variety of applications where systems of equations are estimated. If the systemwise test leads to rejection, single equation F-test will then be used to help identify specific problems. The systemwise testing approach is illustrated by modelling Swedish consumer demand for milk. The example illustrates how the approach can be used to solve issues regarding dynamic specification of models, structural change and other forms of model misspecification.     

Use of quadratic terms in Type 2 Tobit models

A Type 2 Tobit model with a common set of regressors in the selection and regression equations is identified by the nonlinearity of the distribution function. The estimates are relatively less precise than in cases where there are at least some distinct regressors in the two equations. In an attempt to overcome this problem, some authors introduce quadratic terms into one or both equations. As this does not add any new statistical information, just a deterministic function of an existing regressor, the sceptic would question how this could improve the reliability of the estimates. This article shows that arbitrary use of quadratics is not without consequence. It increases the chances of getting either multiple roots, no root or a local root where a global does not exist. The nature of this problem is illustrated with Monte Carlo methods as well as several examples from the literature.     

Similitudes and Discrepancies in Post‐Keynesian and Marxist Theories of Investment: A Theoretical and Empirical Investigation1

There has been a substantial amount of convergence between post‐Keynesian and Marxist economics, the writings of Kalecki being common ground for both traditions. Still, some differences remain. While authors in both traditions seem to agree to a large extent on short‐period issues, long‐period matters relating to the role of saving, the rate of profit, inflation, crowding out, excess money supply, are still contentious. All this seems to depend on the exact form taken by the investment function, more specifically the role of capacity utilization. Four different equations are set up to be tested, two of which correspond to two variants of the Marxist view, while the other two equations correspond to a naive and a sophisticated Kaleckian view, the latter being based on hysteresis. The equations are tested on three sets of annual Canadian data. Various statistical tests are applied to all four equations in an effort to rank them, notably information and encompassing tests. The Kaleckian equation with hysteresis generally comes out empirically with the preferred statistical properties, when manufacturing data on actual rates of capital accumulation are considered separately or when both realized and intended rates of investment for the total industrial sector are used.     

Fuel Prices,Sales Taxes and Passenger Car Market Shares in New Zealand, 1963–1978*

This paper estimates a set of market share equations for new passenger cars in New Zealand over the period 1963 to 1978. These equations are then used to determine the effects on market shares of the fuel price increases and tax rate changes that occurred in the 1970s. The results indicate that the fuel price increases had a major impact on market shares, but that the tax changes probably did not.     

Estimating export equations: a survey of the literature

Export is an important component of national income. It is one of the main determinants of the development level of countries. Both developed and developing countries formulate policies to increase their exports, to increase quality, technology and value added of exported products and to gain competitive advantage in world markets. Export equations provide valuable information regarding this decision making process. Aim of this study was to conduct a survey on extensive literature on estimation of export equations. The literature on export equations can be grouped mainly into four levels of analysis from macro to micro: aggregated level exports, country-level, sector-level and firm-level analyses. In this study, we have surveyed the literature on each level. In the last part, a survey of econometric techniques used in estimation of export equations has been provided, as well.     

COMET: A medium-term macroeconomic model for the European economic community

COMET is a macroeconomic medium-term model for the European Economic Community. It basically consists of eight similarly specified country models which are linked by bilateral trade equations and equations specifying the formation of import and export prices. The medium-term nature is reflected in the role played by the degree of capacity utilization. Section 2 discusses the basic (structural) assumptions of the model, section 3 the performance of the model as a whole.     

The term structure of interest rates during a financial reform: Argentina 1977-81

This paper studies the term structure of interest rates in Argentina following the financial and monetary reforms of 1977 which mainly entailed the liberalization and deregulation of the financial system. Using first order conditions from the international capital asset pricing model, we derived a set of term-structure equations expressed in terms of returns data alone. Empirical implementation of these equations yielded results that are consistent with an important degree of time variation in term premiums.     

Estimation of a system of linear dynamic asset demand equations: Computational considerations

The error covariance matrix of a system of linear dynamic asset demand equations is of less than full rank. This property requires that system be modified before estimation. We show that a knowledge of the structure of the asset equations can be the basis for a favourable reduction in the size of the problems of estimation and inference. It is possible to obtain computational savings while retaining all the properties of the original system.     

An analysis of the demand for housing attributes

This paper uses a two-step approach to estimate a system of structural demand equations for housing attributes. Estimation of a hedonic price regression, in the first step, yields implicit prices for housing attributes for the Toronto Metropolitan area in 1978, which are then used to estimate the expenditure share equations derived from the indirect translog utility function. Empirical results indicate that the composite housing attributes (used in the second stage model) are own-price elastic, while an examination of cross price relationships reveals that these attributes are reasonably substitutable.     

A Further Comment on the Zero Row-Sum Property of Mean-Variance Portfolio Allocation Models

This note considers the conditions under which asset demand equations arising out of mean-variance portfolio allocation models have symmetric interest rate effects. If these conditions are satisfied, it is also valid to write the asset demand equations as functions of interest rate differentials rather than interest rate levels.
The necessary condition for symmetry is that the 'expected return effect' be equal to zero. This will not always be the case and therefore symmetry of interest rate effects is an hypothesis which should be tested rather than a restriction which can be imposed on estimated asset demand equations. Statistical tests of this restriction often lead to its rejection.     

Testing price equations

How inflation and unemployment are related in both the short run and long run is perhaps the key question in macroeconomics. This paper tests various price equations using quarterly U.S. data from 1952 to the present. Issues treated are the following. (1) Estimating price and wage equations in which wages affect prices and vice versa versus estimating “reduced-form” price equations with no wage explanatory variables. (2) Estimating price equations in (log) level terms, first difference (i.e., inflation) terms, and second difference (i.e., change in inflation) terms. (3) The treatment of expectations. (4) The choice and functional form of the demand variable. (5) The choice of the cost-shock variable. The results suggest that the best specification is a price equation in level terms imbedded in a price-wage model, where the wage equation is also in level terms. The best cost-shock variable is the import price deflator, and the best demand variable is the unemployment rate. There is some evidence of a nonlinear effect of the unemployment rate on the price level at low values of the unemployment rate. Many of the results in this paper are contrary to common views in the literature, but the empirical support for them is strong.     

A theory of dynamic oligopoly,III: Cournot competition

We study the Markov perfect equilibrium (MPE) of an alternating move, infinite horizon duopoly model where the strategic variable is quantity. We exhibit a pair of difference-differential equations that, when they exist, differentiable MPE strategies satisfy. For quadratic payoff functions, we solve these equations in closed form and demonstrate that the MPE corresponding to the solution is the limit of the finite horizon equilibrium as the horizon tends to infinity. We conclude with a discussion of adjustment costs and endogenization of the timing.     

European Integration and Manufactures Import Demand: An Empirical Investigation of Ten European Countries

This paper studies import demand in ten European countries over the period 1970–95, and our objective is to investigate whether the process of European integration has affected imports. We provide evidence for parametric change in traditional import demand equations, suggesting that important variables or structural factors are missing from the long-run equations. We present equations based on new trade theory, where effects of technology and foreign direct investment are present. Once we include these there is little evidence that the creation of the Single Market has directly increased aggregated imports in European countries.     

A model for capital movements in Finland's balance of payments

In this paper a disaggregated quarterly model for capital movements in Finland's balance of payments is presented. This model is one block of the Bank of Finland quarterly econometric model of the Finnish economy.The structural equations are seen, in the case of Finland, mainly from the demand side. These equations are derived using the expected utility framework. However, supply conditions, in the form of domestic credit rationing and especially in the form of extensive controls on international capital movements, also play a considerable role.     

Tax policy and investment in major U.S. macroeconomic econometric models

In an analysis of six major U.S. quarterly models, the predicted results of tax incentives for investment are found to vary widely. Differences are traced to critical specifications in investment equations. When appropriately revised investment equations are reestimated the role of tax parameters is much reduced, particularly among the high outliers, and the variance among the models is narrowed decidedly. Full model simulations of revised equations suggest that current and proposed incentives such as the investment tax credit and accelerated depreciation are not cost-effective. Increases in investment approximate only half of static tax losses, and budget deficits widen.     

The equations unveiled: Sraffa's price equations in the making

In the first part of Production of Commodities by Means of Commodities,four equation systems are introduced: three are drawn up inorder to solve the problem of relative prices; the last oneis devised to define a suitable standard of prices. The bookwas published in 1960, but—as we are told in the preface—its‘central propositions’ and a first version of theprice equations had been originally conceived and written morethan 30 years before, when the author was still in his twenties.Having access now to the Sraffa Papers, preserved in the WrenLibrary, we can ascertain the intellectual origin of the equations.In this paper the analytical path that led to the final draftof the price equation is followed, step by step, and the linkbetween these equations and Sraffa's quest for an ‘invariablestandard of value’ is clarified.