A theory of natural addiction

Economic theories of rational addiction aim to describe consumer behavior in the presence of habit-forming goods. We provide a biological foundation for this body of work by formally specifying conditions under which it is optimal to form a habit. We demonstrate the empirical validity of our thesis with an in-depth review and synthesis of the biomedical literature concerning the action of opiates in the mammalian brain and their effects on behavior. Our results lend credence to many of the unconventional behavioral assumptions employed by theories of rational addiction, including adjacent complementarity and the importance of cues, attention, and self-control in determining the behavior of addicts. We offer evidence for the special case of the opiates that “harmful” addiction is the manifestation of a mismatch between behavioral algorithms encoded in the human genome and the expanded menu of choices faced by consumers in the modern world.     

非均衡的经济动态模型

本文旨在按现实世界的本来面目建立一个非均衡的内生经济动态模型。在这个模型中 ,源于部门内和部门间关系的内生变量导致资本市场、消费品市场上产量和价格的波动。市场的非均衡过程、存货调节机制以及经济人的最优行为和适应性行为是基于对现实世界的观察进行模拟的。静态性质及其稳定性是作为一般市场动态过程的特例加以讨论的。     

Government financing in an endogenous growth model with financial market restrictions

Summary. In this paper, we develop an endogenous growth model with market regulations on explicitly modeled financial intermediaries to examine the effects of alternative government financing schemes on growth, inflation, and welfare. In the presence of binding regulation, there is always a unique equilibrium. We perform four alternative policy experiments; a change in the seigniorage tax rate, a change in the seigniorage tax base, a change in the income tax and a change in the fiscal-monetary policy mix. We find that in the presence of binding legal reserve requirements, a marginal increase in government spending need not result in a reduction in the rate of economic growth if it is financed with an increase in the seigniorage tax rate. Raising the seigniorage tax base by means of an increase in the reserve requirement retards growth and it has an ambiguous effect on inflation. An increase in income tax financed government spending also suppresses growth and raises inflation although not to the extent that the required seigniorage tax rate alternative would. Switching from seigniorage to income taxation as a source of government finance is growth reducing but deflationary. From a welfare perspective, the least distortionary way of financing an increase in the government spending requirements is by means of a marginal increase in the seigniorage tax rate. Under the specification of logarithmic preferences, the optimal tax structure is indeterminate. Received: March 20, 2000; revised version: June 26, 2001     

Tax Competition and Redistribution in a Two-Country Endogenous-Growth Model

This paper examines the effects of policy coordinationin a two-country world with endogenous growth and imperfect capitalmobility. Redistribution is financed by a source-based capital-incometax. Comparing the cases in which countries do and do not coordinatetheir fiscal policies, it is shown that redistribution can beinefficiently high if fiscal policies are not coordinated. Thisis because the negative effects of fiscal policy on home savingsaffect economic growth abroad by inducing a decline in foreigninvestment. This externality can dominate the well-known tax-baseexternality.     

On the distributional effects of exchange rate fluctuations

How do exchange rate movements affect different sectors of an economy? We address this question in a simple general equilibrium model, stressing the different exposures of various sectors to foreign competition, an aspect ignored in earlier contributions. The impact of exchange rate shifts is highly heterogenous across sectors. While a depreciation leads to a substantial competitiveness and welfare gain for agents with a high exposure to foreign competition, agents facing mostly domestic competition are adversely affected.     

A new look at variation in employment growth in Canada: The role of industry,provincial, national and external factors

We examine fluctuations in employment growth using Canadian data from 1976 to 2010. We consider a wide range of models and examine the sensitivity of our findings to modelling assumptions. The results from our most preferred model, which we selected using the Bayesian Information Criteria, indicate that most of the variance in employment growth that is not due to the idiosyncratic error comes from domestic sources, with most of this coming from industry and provincial factors. Overall, we find that external and national factors play a much smaller role in employment fluctuations than in earlier research. We provide some possible explanations for these differences and discuss the implications of our findings for public policy and theory.     

Noisy signaling in discrete time

This paper characterizes the equilibrium set of a dynamic noisy-signaling model in discrete time. A seller privately knows the quality of her asset. She can exert a costly effort to generate stochastic returns. Buyers stochastically arrive over time and, after observing the history of returns, they make price offers. In our model, the equilibrium behavior of the buyers is discontinuous: they only make acceptable (high) offers if the posterior about the quality is above a given threshold. As a result, the recursive nature of the model replicates the discontinuity, giving the equilibrium continuation payoff a complex self-replicating structure that may take the form of a devil’s staircase.     

Capital maintenance and depreciation over the business cycle

This paper develops and estimates a stochastic general equilibrium model with capital maintenance, which affects endogenously the depreciation rate of capital. The estimate of maintenance series is found to track survey-based measures for Canada quite closely and to generate the procyclical pattern of maintenance observed in the data. We use our model estimates to infer the time profile of equipment capital depreciation in Canadian and US manufacturing. The depreciation rate is estimated to be volatile and highly procyclical in both countries.     

Multiple equilibria in the Aghion–Howitt model

We show that the simple Aghion–Howitt model exhibits oscillatory indeterminacy in the process of creative destruction as firms undertaking new research do not internalize their effect on existing firms. A simple calibration shows that indeterminacy occurs for quite plausible parametrizations of the share of the intermediate good.     

A general endogenous grid method for multi-dimensional models with non-convexities and constraints

The endogenous grid method (EGM) significantly speeds up the solution of stochastic dynamic programming problems by simplifying or completely eliminating root-finding. We propose a general and parsimonious EGM extended to handle (1) multiple continuous states and choices, (2) multiple occasionally binding constraints, and (3) non-convexities such as discrete choices. Our method enjoys the speed gains of the original one-dimensional EGM, while avoiding expensive interpolation on multi-dimensional irregular endogenous grids. We explicitly define a broad class of models for which our solution method is applicable, and illustrate its speed and accuracy using a consumption–saving model with both liquid assets and illiquid pension assets and a discrete retirement choice.