Imperfect capital markets and life-cycle consumption

This paper develops a long-range consumption planning model which, unlike conventional life-cycle theory, admits a disparity between borrowing and lending rates of interest. It is shown that, when capital markets are imperfect, optimal consumption depends not only upon an arithmetic average of the household's intertemporal income distribution, the traditional life-cycle income variable, but also upon current income and higher-order moments of that income distribution. The consumption function is estimated using the 1967–1968 CEDE budget survey of four major Colombian cities. A test is made to determine whether the assumption of perfect capital markets is acceptable for empirical approximation. The results strongly indicate that, for households in middle and lower income classes, the explanatory power of the consumption function can be raised by introducing a more flexible life- time budget constraint. The model is then estimated and used to compute the marginal consumption responses of Colombian households to transitory and permanent income changes.     

Neoclassical life-cycle consumption: a textbook example

Summary.   We present a simple neoclassical life-cycle model in continuous time, in which the effects of endogenous labor supply, uncertain lifetime, and family composition on consumption and income profiles are jointly analyzed. Due to a parsimonious specification, analytical solutions for consumption growth are available for constant intertemporal elasticity of substitution preferences. Without relying on borrowing constraints, the model can generate a hump in the consumption profile, and a comovement of consumption and income during working life. Received: June 9, 1999; revised version: October 4, 1999     

Innovation over the industry life-cycle: Evidence from EU manufacturing

Empirical research has revealed some regularities regarding the innovation that takes place over the industry life-cycle. First, innovation is high when an industry is young and low when the industry matures, and second, product innovation decreases with industry maturity, while process innovation increases. The implications of these regularities are profound, but evidence is to date largely case based and it is hard to generalize and draw policy conclusions. We use a flexible measure of maturity and a novel modeling approach to investigate innovation patterns for 21 European manufacturing industries. Our results strongly support both assertions and lend support to life-cycle based R&D-policy.     

Reassessing the effects of environmental taxation when pollution affects health over the life-cycle

We introduce the link between pollution, morbidity and productivity over the life-cycle in a two-period overlapping generations model. As the environmental tax improves the health-profile over the life-cycle, it influences saving, investment in health, labor supply and retirement. As a result, we identify effects of environmental taxation beyond the standard crowding-out and productivity effects captured by the past literature. We show that whether those effects are positive or negative for the economy crucially depends on the degree of substitutability between young and old labor. Our numerical examples suggest that that those new effects alleviate the negative effects of environmental taxation on output and decrease potential positive welfare effects.     

Overconfidence and consumption over the life cycle

Overconfidence is a widely documented phenomenon. In this paper, we study the implications of consumer overconfidence in a life-cycle consumption/saving model. Our main analytical result is a necessary and sufficient condition under which any degree of overconfidence concerning the mean return on savings can produce a hump in the work-life consumption profile. This condition is almost always met in the data. We show by simulations that overconfidence concerning the variance of the return can have little effect on the long-run average behavior of consumption over the life cycle, and that our basic conclusion is fairly robust with various realistic modifications to the baseline model. We interpret the general applicability of our analytical framework and discuss our numerical results in the light of aggregate consumption data.     

中国农村居民消费的过度敏感性分析

笔者以消费理论为基础,运用1985年～2007年我国农村居民人均实际消费和收入的年度数据,采用协整分析和误差修正对农村居民消费的过度敏感性进行分析,得出我国农村居民消费表现出过度敏感性特征的结论,并分析了其原因.为解决我国内需不足,开拓农村消费市场,有必要采取一系列措施,矫正农村居民消费的过度敏感性,以实现我国经济持续稳定增长、农民生活水平逐步提高的目标.     

Trend-reverting fluctuations in the life-cycle model

Aggregate time series provide evidence of short-term dynamic adjustment that appears to be governed by complex or negative real eigenvalues. This finding is at odds with the predictions of reasonably parameterized, convex one-sector growth models with complete markets. We study life-cycle economies in which aggregate saving depends non-trivially on the distribution of wealth among cohorts. If consumption goods are weak gross substitutes near the steady-state price vector, we prove that the unique equilibrium of a life-cycle exchange economy converges to the unique non-monetary steady state via damped oscillations. We also discuss examples and extensions.     

The industry life-cycle of the size distribution of firms

This paper analyzes the evolution of the distributions of output and employment across firms in U.S. manufacturing industries from 1963 until 1997. The firm size distribution changes significantly as an industry goes through stages of its life-cycle. The evolutions of the employment and output distributions also differ significantly, but display strong inter-industry regularities, including that the nature of the evolution depends on whether the industry is experiencing growth, shakeout, maturity, or decline. The observed patterns have implications for theories of industry dynamics and evolution.     

Imperfect capital markets in empirical life-cycle models

In the context of Frisch demand functions that have prices and the marginal utility of income as independent variables, we show how to incorporate imperfect capital markets into empirical models. The analysis is for rational agents in an uncertain world.     

A life-cycle analysis of social security with housing

This paper incorporates two features of housing in a life-cycle analysis of social security: housing as a durable good and housing market frictions. We find that both housing quantities and homeownership rates respond strongly to eliminating social security. Accordingly, the aggregate impacts of this policy reform are significantly larger in an economy with explicit housing choices than in a standard life-cycle economy. Our analysis shows that the key mechanism behind these results is the substitution effects of a change in interest rates and, thus, the price of housing services on the choice of nondurable consumption versus housing services.     

An analysis of life-cycle accumulation of financial assets

This paper uses data from the Consumer Expenditure Survey (CEX) to estimate age profiles for financial asset accumulation. While the CEX is not designed to estimate financial wealth, it has the advantage of being available on a consistent basis since 1980.As the data set is not a panel, synthetic cohort techniques are used to analyse the dynamics of asset accumulation over the life cycle, while allowing for cohort and business cycle effects. It is shown that it is not possible to separately identify cohort and age effects in the level of financial assets. However, with the specification proposed, it is possible to identify all the parameters (except the intercept) of the age profile for the changes in financial assets.Several measures of location are analysed, and several conditioning variables considered. The results seem to indicate a decline in the rate of financial asset accumulation in the last part of the life cycle. However, because the scale of this effect is not identified, these results cannot be used to address the issue of asset decumulation by the elderly.     

Health insurance and consumption: Evidence from China’s New Cooperative Medical Scheme

We exploit a quasi-natural experiment arising from the introduction of a health insurance program in rural China to examine how the insurance coverage affects household consumption. Results show that, on average, the health insurance coverage increases nonmedical-related consumption by more than 5%. This insurance effect is observed even in households with no out-of-pocket medical spending. In addition, the insurance effect is stronger in households with worse self-reported health status. These results are consistent with the precautionary savings argument. The insurance effect also varies by household experience with the program. In particular, the effect is significant only in villages where some households have actually obtained reimbursement from the insurance program. The program within these villages stimulates less consumption among new participants than among households that have participated in the program for more than a year.     

医改周期:基于15国百余年医改事件的结构化分析

通过对15个样本国家百余年的医改事件运用结构化的分析方法,经过对医改理论分型、结构化指标构建、样本确定、文献标准化处理和统计分析等步骤,文章提出了医改周期的概念并解释了医改周期现象,归纳了医改周期的阶段性特点,对医改现象的普遍性和规律性进行了探讨,最后提出了对中国医改发展阶段的基本判断。     

A note on the life-cycle search and matching model with segmented labor markets

Recently, there has been renewed interest in labor search and matching models that incorporate a life-cycle structure by assuming finite horizons. Existing studies provide detailed analyses on the age dynamics of job creation and destruction, assuming that workers of all ages search for jobs in the same market. This paper examines a related environment that has drawn less attention, where the labor market is exogenously segmented by age. The paper finds sufficient conditions for the model to yield unambiguous predictions on the age profiles of key variables, and compares them with the corresponding conditions in models with a single market. The paper further examines the age profiles of these key variables in the efficient allocation. In particular, with no persistence in idiosyncratic match productivity, the efficient allocation is found to exhibit monotonic age profiles for the job finding and separation rates.     

Characterizing life-cycle wealth distributions using statistical inference and dominance criteria

This paper examines how the distribution of household wealth in Canada varies with age over the life cycle. The wealth distribution is characterized in terms of decile means and decile shares for each of six age groups, and comparisons between age-specific distributions are based on first-and second-order stochastic dominance criteria. It is found that (i) mean wealth levels and wealth distributions increase significantly with age in concave quadratic fashion until near-retirement and then decline, and (ii) wealth inequality declines in convex fashion with age, at first steeply and then not significantly. This joint pattern in mean and inequality of wealth holdings across age groups presents a challenge for basic theories to explain.     

Product classification to support approximate life-cycle assessment of design concepts

Many companies are beginning to change the way they develop products due to increasing awareness of sustainable development. Designers, who play a key role in product development, are being asked to incorporate environmental criteria into the design process. The need for analytically based conceptual design methods for integrated life-cycle assessment (LCA) has motivated the development of an approximate life-cycle assessment concept based upon learning algorithms. Although preliminary tests on general approximate models showed promise, it was observed that grouping products to create specialized learning surrogate LCA models for different classes of products might further improve results. This paper presents work to develop an automated classification system to support the specialization of surrogate LCA models for different groups of products. Hierarchical clustering is used to guide a systematic identification of product groups based upon environmental categories. These groupings are then used to create automated classification schemes using the C4.5 decision tree algorithm. Although further data are needed to induce good generalization performance, resulting product classification systems are considered to be a viable approach to support specialized learning surrogate LCA models for different classes of products.     

Self-insurance in a life-cycle model of labour supply and savings

This paper analyses the incentives to work and to save over the life cycle in the presence of incomplete markets. In a calibrated, partial equilibrium model, flexibility in hours worked changes asset age-profiles: borrowing when young is greater and saving when middle-aged is greater than when labour supply is fixed. Uncertainty causes individuals to work longer hours and to consume less when young. With flexibility over hours, accumulating precautionary assets incurs less of a utility cost and so the level of saving is greater. Further, allowing for flexibility and uncertainty means simulated hours of work and consumption more closely match the age profiles in the data.     

Participation and hours of work: Two stages in the life-cycle of married women

A 1979 cross-section of Dutch households is used to estimate an integrated labor force participation and hours of work labor supply model for women. Young women and older women are found to behave differently. Wage and income elasticities are always higher for older than for younger women (in absolute terms), and the relative importance of participation and hours elasticities is reversed as the average woman grows older, thereby implying that younger women tend to be more preoccupied with the participation decision whereas older women are more concerned with the hours decision. Econometrically the paper builds on Heckman's (1974) participation cum-hours model by adapting the estimation method to allow for the fact that hours worked are only observed in intervals. A maximum likelihood model in which we integrate over parts of the hours distribution is used. This technique, though computationally involved, gave satisfying results. We compare the results with estimates of a similar but much simpler probit model to identify the possible biases in the simpler approach.     

Market share instability and stock price volatility during the industry life-cycle: the US automobile industry

Market share instability, during certain stages of the industry life-cycle, has become a stylized fact in the industrial organization literature. In the finance literature, volatility in the form of excess volatility, i.e. the much larger volatility of stock prices than dividends (although stock prices should in theory trace the present value of future dividends), has given rise to controversies regarding stock price determination (Campbell and Shiller, 1988; Shiller, 1989). Recent evolutionary models, both theoretical and empirical, have tied the presence of market share instability to industry specific variables, such as specific periods in the industry life-cycle and specific “technological regimes”. The object of the paper is to explore whether there is a relationship between market share instability and stock price volatility and to what degree this relationship is connected to the concept of the industry life-cycle, and hence to industry specific factors. To do so, we explore the relationship in one particular industry, the US automobile industry. Since neither life-cycle nor finance theories attack this problem directly, we use insights from both approaches to build hypotheses which guide the data analysis. The empirical results confirm many of these hypotheses, suggesting that the degree of excess volatility is indeed partly affected by industry specific factors.