Stochastic growth: a duality approach

We re-examine the representative agent's optimal consumption and savings under uncertainty in the presence of investment constraints using martingale representation and convex analysis techniques. This framework allows us to explicitly quantify precautionary savings which induces a higher average growth rate than in a certainty setup. We provide a closed form solution for a Cobb-Douglas economy. The effect of uncertainty on portfolio selection is analyzed. Consumption growth rate and risk free interest rate exhibit a U-shaped relationship. Uncertainty negatively affects expected consumption growth rate; such a result seems to be supported by empirical evidence.     

Sector-specific minimum wages,economic growth,and some policy implications

Economic growth is introduced in the urban unemployment model of Harris and Todaro. It is shown that in the steady state, the optimal savings ratio is greater than the golden rule savings ratio under full employment. Also the optimal proportion of total investment allocated to the urban sector is not necessarily higher than the optimal proportion under full employment.     

Stochastic growth with correlated production shocks

This paper extends the stochastic growth model of Brock and Mirman [J. Econ. Theory4 (1972), 497–513] to allow the production shocks to be correlated over time. The resultant optimal savings and consumption policies depend not only upon the current level of output but also upon the most recent realization of the random shock. The properties of these policy functions are studied and it is shown that the Markov process on output, capital stock and consumption resulting from the application of these policies converges to a stationary distribution.     

Tax-mix, public spending composition and growth

This paper characterizes optimal fiscal policy in an endogenous growth model whose policy implications are consistent with the relationship between two stylized facts observed in a majority of OECD economies, namely the growth in the ratios of both government consumption to public investment and of direct to indirect taxation from 1970 to 2004. Assuming a continuation in the upward trend for the public consumption to output ratio consistent with that observed for this variable between 1970 and 2004 for most developed economies, we find that the optimal tax system becomes more intensive in income taxation relative to consumption taxation, and that public disbursements become less intensive in public investment, which is consistent with the co-evolution of these ratios over the last 40 years.     

Optimal growth theory: Challenging problems and suggested answers

We argue that optimal economic growth is confronting serious applicability problems, having nothing to offer in these days of high public deficits accompanied by high unemployment rates. In particular, the theory is not capable of indicating optimal savings rates; those are systematically in ranges that can be considered as unacceptable, or are accompanied by unrealistically high real growth rates. Faulty is the systematic use of arbitrary utility functions, which turn out to be contradictory to competitive equilibrium. We then show how relying on the hypothesis of competitive equilibrium yields reasonable, perfectly acceptable numbers for the optimal savings rate.     

An optimal monetary policy in an aggregate neoclassical model of economic growth

This paper shows that the usual Ramsey-Cass-Koopmans optimal-growth theory is applicable to decentralized monetary economies and illustrates, with a simple model, how optimal growth can be achieved via a simple monetary policy. Securities and the endogeneity aspect of the money supply are explicitly introduced. This paper shows that the steady state under optimal growth is a saddle point, that the dynamic behavior of the capital-labor ratio and real per capita consumption is identical to that found in the usual literature in which money is not introduced, and that the optimal monetary policy is “counter-cyclical.”     

Substitution Between Private and Public Consumption in Australia*

Large increases in the private sector's savings ratio during a period of rapid growth in the relative size of the public sector has led to the suggestion that substitution between private and public consumption may be an important fcature of the Australian economy (Clements 1979). In this paper, empirical estimates are presented which indicate that no such substitution exists The estimates are derived from a theoretical model of consumption which is based on inter-temporal optimization in a stochastic environment. The estimates also suggest that private sector consumption behaviour is consistent with the joint hypothesis of rational expectations and Ricardian equivalence     

Sustainable development,the Hartwick rule and optimal growth

Defining sustainable development as non-declining utility, the consistency of this concept with the Hartwick rule and optimal growth is explored when resources are exhaustible. A simple proof that a generalized Hartwick rule is necessary and sufficient for constant consumption is derived. The existence of a maximal constant consumption path is shown to depend critically on the elasticity of substitution; if this is less than 1, consumption declines; if it is greater than 1 then consumption is not maximal; if it is equal to 1 (the Cobb-Douglas case) then existence is proved. Consumption can increase along an optimal path if the pure rate of time preference is 0; if it is non-zero then consumption declines.     

Optimal unemployment insurance: transitional dynamics vs. steady state

In this study, we ask whether the presence of precautionary savings substantially reduces the optimal replacement rate in an European economy type characterized by high unemployment benefits and moral hazard. We build a simple job search model calibrated on French data and, in line with previous studies, find that the optimality criterion based on comparisons of steady states leads to a low optimal ratio. Yet, this result ignores potential transitional costs due to the necessity for agents to increase their savings and reduce their consumption whenever the ratio is cut. We therefore build a dynamic model taking full account of the transition, and show that a reduction in benefits reduces welfare. Even though the long-run optimal replacement rate is lower than the current one, transitional costs dominate long-run gains.     

Uncertainty in the public debt market and stochastic long-run growth

In a continuous time model, a representative household has to allocate its investment and consumption in an optimal manner under conditions of uncertainty. In the present study it is hypothesized that there are two types of assets: a risk-free and a risky asset. The risk-free asset is assumed to be the physical capital, while at the same time uncertainty is allowed to result from the exogenous random variations in the public debt market, rendering in this way government bonds to act as the risky asset. In the endogenous growth framework with productive public investment, the expected long-run growth rate, the dynamic path of consumption as well as the optimal allocation of investment between a risky and a riskless asset, are analytically derived. This kind of treatment allows us to create a locus for the long-run growth over the various levels of uncertainty. The outcome of the analysis is that a rise in uncertainty impacts negatively upon the long-run growth rate. In order to empirically assess the relationship between growth and uncertainty, we lay our emphasis on the US economy for the period 1957:1 to 2008:4. Within the framework of a bivariate BEKK–GARCH(1,1)-M model a significant negative relationship between uncertainty and economic growth has been established.     

The analytical solution of balanced growth of non-linear dynamic multi-sector economic model

In a one-sector neoclassical dynamic economic growth model, a reasonable ratio of investment to consumption exists, i.e., the “Golden Rule of Consumption”. This study is to extend one-sector neoclassical growth model to a multi-sector one. It is assumed that both the production function and the utility function are of Cobb–Douglas type, and the analytical expression of the balanced growth solution of the multi-sector model is provided, mainly including analytical expressions of the optimal distribution coefficient of fixed capital investment, the optimal distribution coefficient of labor hour, the proportion of production, the economic growth rate, the rate of change of the price index, and rental rates of different fixed capital.     

Determinants of household savings in China and their role in quasi‐money supply1

This study derives household saving potential empirically from econometric models of Chinese urban and rural household consumption and uses this potential to explain household bank deposits. Model simulations are performed to analyse the effects of interest rates, income and income uncertainty on the saving potential and the bank deposits. The bank deposits variable is then used to explain quasi‐money supply. High bank absorption of household savings is found to account mainly for the rapid growth in quasi‐money, which in turn explains the exceptionally high M2/GDP ratio. Households’ savings are largely predictable from their regular consumption.     

Intertemporal consumption and debt aversion: an experimental study

This paper tests how subjects behave in an intertemporal consumption/saving experiment when borrowing is allowed and whether subjects treat debt differently than savings. Two treatments create environments where either saving or borrowing is required for optimal consumption. Since both treatments share the same optimal consumption levels, observed consumption choices can be directly compared across treatments. The experimental findings imply that deviations from optimal behavior are higher when subjects have to borrow than when they have to save in order to consume optimally, suggesting debt aversion. Signifiant under-consumption is observed when subjects have to borrow in order to reach optimal consumption. In line with previous experiments, weak evidence is found suggesting that subjects over-consume when saving is necessary for optimal consumption.     

Sustainable per capita consumption under population growth

We establish two investment rules for maximal constant per capita consumption under exogenous population growth, one in terms of total capital stocks and the other in terms of per capita capital stocks. Both rules show the importance of the development of future population growth. The investment rules are illustrated in the one-sector model of capital accumulation, the DHSS model of capital accumulation and resource depletion, and the Stollery–d’Autume–Schubert model in which natural capital provides amenities. Application to recent empirical evidence indicates that actual genuine savings might be insufficient to sustain per capita consumption, when future population growth is combined with a large per capita consumption-wage gap.     

Optimal growth when consumption takes time

This article analyzes a one‐sector growth model where the consumption takes time. When the consumption takes time, the consumption set is compact and we meet satiety. However, we prove that dynamic constraints are binding. This result is crucial to prove that, under well‐known assumptions in macroeconomic dynamic programming, the optimal path is monotonic and always converges to a unique nontrivial steady state as in the case where consumption is timeless.     

The effect of precautionary saving on consumption in Sweden

Uncertainty concerning future income lowers consumption. This is often called the precautionary demand for savings. In this paper the existence of precautionary savings. In this paper the existence of precautionary saving is investigated using Swedish data for the years 1973–1992. As there are no variables for consumers' uncertainty a proxy is used. Assuming an underlying distribution of attitudinal data, a variance series is derived. Including the proxy in different specifications of the consumption function, indication of precautionary saving can be found. As a result, no uncertainty would raise consumption by 4.9%.     

Relative consumption, economic growth, and taxation

This paper studies the influence of consumption externalities in the Ramsey model. In contrast to the recent literature, a quite general specification of preferences is used and the concept of the effective intertemporal elasticity of substitution is introduced. We give conditions for the observational equivalence between economies with consumption externalities and externality-free economies. An additional key result is that there exist several types of instantaneous utility functions in which the decentralized solution coincides with the socially planned one in spite of the presence of consumption externalities. The conditions for optimal taxation are also derived.     

Population growth and savings rates: Some new cross‐country estimates

It is widely recognised that population growth can have two conflicting effects on savings. It reduces savings as it leads to more dependent children, but if balanced it can also increase savings by increasing the number entering the working part of the life cycle and hence the number of potential savers. However, this positive effect has largely been ignored in the empirical literature. Based on the population growth rate as its measure and an augmented cross‐country life cycle regression model evidence for its existence is confirmed. Confidence in the estimates is undermined by tests indicating that in many countries over the relevant period population growth was not in steady state balance. This is ameliorated by the high regression R²s and by comparable labour force growth rate estimates, but it was also found that the estimates could not be interpreted as evidence that countries with more rapid population growth rates actually save more. This is because the negative impact of larger families was found to outweigh any increase in savings because of more families. The net elasticity effect was calculated to be ??0.08. The paper concludes that savings continues to be a cost of rapid population growth, but perhaps not quite as debilitating as some might have presumed.     

Money as a medium of exchange and monetary growth in an underdevelopment context

This paper constructs a neoclassical monetary growth model applicable to less developed economies, in that (1) the economy is assumed to be labour-surplus (as a result of which its steady-state growth rate is an endogenous variable), and (2) differential savings propensities on the part of profit- and wage-earners are postulated. The model predicts that an increase in the rate of monetary expansion increases the steady-state rate of inflation, increases the capital-labour ratio, reduces the money-labour ratio, and reduces the steady-state growth rate. Because of this last-mentioned fact, an inflationary policy is held to be unfavorable to economic development, despite the fact that it increases the capital-labour ratio. Some implications of the analysis for the well-known ‘choice of techniques’ problem are also discussed.     

流动性约束和不确定性状态下的预防性储蓄研究-中国城乡居民的消费特征分析

该文利用我国城乡时间序列数据,对城乡居民的消费特征做了新的探索.我们对引入预期收入增长的对数线性欧拉方程和二阶泰勒近似的欧拉方程进行了估计,结果说明,当期收入仍是决定我国居民消费的主要因素,消费的随机游走假说不成立;城镇居民比农村居民有更强的预防性储蓄动机.1990年代中期以来持续走低的收入增长率直接抑制了消费需求的增长,而仍然偏紧的流动性约束和日益增强的不确定性增大了预防性储蓄动机.