Educational Attainment and Family Background

Abstract. This paper analyses the effect of aspects of family background, such as family income and parental education, on the educational attainment of persons born from 1967 to 1972. Family income is measured at different periods of a child's life to separate long-term versus short-term effects of family income on educational choices. We find that permanent income matters to a certain degree, and that family income when the child is 0–6 years old is an important explanatory variable for educational attainment later in a child's life. We find that short-term credit constraints have only a small effect on educational attainment. Long-term factors, such as permanent family income and parental education, are much more important for educational attainment than are short-term credit constraints. Public interventions to alleviate the effects of family background should thus also be targeted at a child's early years, the shaping period for the cognitive and non-cognitive skills important later in life.     

Innovation timing games: a general framework with applications

We offer a new algorithm for analyzing innovation timing games. Its main advantage over the traditional approach is that it applies to problems that had previously been intractable. We use the algorithm to examine two classical innovation problems. We find that the competition takes the form of a waiting game with a second-mover advantage either for any level of R&D costs (process innovation) or for high R&D costs (product innovation). Moreover, both models predict that the second-mover advantage is monotonically increasing in the costs of R&D.     

Overnight borrowing, interest rates and extreme value theory

We examine the dynamics of extreme values of overnight borrowing rates in an inter-bank money market before a financial crisis during which overnight borrowing rates rocketed up to (simple annual) 4000 percent. It is shown that the generalized Pareto distribution fits well to the extreme values of the interest rate distribution. We also provide predictions of extreme overnight borrowing rates using pre-crisis data. The examination of tails (extreme values) provides answers to such issues as to what are the extreme movements to be expected in financial markets; is there a possibility for even larger movements and, are there theoretical processes that can model the type of fat-tails in the observed data? The answers to such questions are essential for proper management of financial exposures and laying ground for regulations.     

GSM/TD-SCDMA系统互操作研究

文章主要介绍GSM/TD-SCDMA系统互操作的原则和策略,分析与总结了GSM/TD-SCDMA网络共存的可行性,提出基于成熟GSM网络的TD-SCDMA网络部署建议,减少投资并快速实现3G商用服务的运营目标。     

An instrumental variable approach for panel unit root tests under cross-sectional dependence

For dynamic panel models with cross-sectional dependence, several unit root tests are constructed using a Huber-type instrument, whose null asymptotics are standard Gaussian and do not depend on nuisance parameters. A Monte-Carlo simulation shows that the proposed tests have better sizes and comparable powers relative to other two existing tests developed for cross-sectionally dependent dynamic panel models.     

THE RELATIONSHIP BETWEEN THE BLACK MARKET AND OFFICIAL EXCHANGE RATES: AN EXAMINATION OF LONG-RUN DYNAMICS IN INDIA

This study is the first to use Johansen's cointegration approach for India in the analysis of the long‐term dynamics between the black and official exchange rates for the period 1953–1993. The study also estimates the long‐run elasticity of the official rate with respect to the black market rate. As monthly data over 40 years are used, and a more robust methodology is employed, the results are likely to be more reliable as compared with the earlier work on India. The results of our study suggest that while there is a long‐term relationship between the two rates, the direction of causality is from the black rate to the official exchange rate. This is plausible in the Indian context where policy has generally lagged behind events in the black market. The hypothesis of a constant black market premium is rejected, implying that there is a mismatch between the percentage change in the official exchange rate and the percentage change in the black market rate.     

Moral hazard and Marshallian inefficiency: Evidence from Tunisia

We formalize the link between optimal cost-sharing contracts and the production technology in the presence of moral hazard by appealing to several well-known results from duality theory. Building on intuitions from the interlinkage literature, we show that optimal contractual structure is determined by the (i) substitution possibilities that exist between different observable factor inputs, as well as (ii) between these inputs and unobservable effort. We endogenize contractual choice using landlord characteristics as instruments, exploiting the fact that, in our dataset, landlords interact with several tenants and vice versa. The approach is applied to an unbalanced plot-level panel of cost-sharing contracts in a Tunisian village, using a translog representation of the restricted profit function. Contractual terms are found to be a significant determinant of input use and therefore lead to Marshallian inefficiency, while the optimality of the underlying contractual structure is rejected.     

Default and aggregate income

This paper studies how default varies with aggregate income. We analyze a model in which optimal contracts enable risk sharing of privately observed, idiosyncratic income by allowing for default. Default provisions allow agents with low idiosyncratic income realizations to repay less and thus provide insurance. Default penalties ensure that only these agents default. We show that default can occur under the optimal contract and that default provisions vary with aggregate income. We provide conditions such that both the amount of default and default penalties vary countercyclically with aggregate income and show that the default rate can be discontinuous.     

On the impact of leverage constraints on asset prices and trading volume

Abstract. Researchers have used stylized facts on asset prices and trading volume in stock markets (in particular, the mean reversion of asset returns and the correlations between trading volume, price changes and price levels) to support theories where agents are not rational expected utility maximizers. This paper shows that this empirical evidence is in fact consistent with a standard infinite horizon – perfect information – expected utility economy where some agents face leverage constraints similar to those found in todays financial markets. In addition, and in sharp contrast to the theories above, we explain some qualitative differences that are observed in the price-volume relation on stock and on futures markets. We consider a continuous-time economy where agents maximize the integral of their discounted utility from consumption under both budget and leverage constraints. Building on the work by Vila and Zariphopoulou (1997), we find a closed form solution, up to a negative constant, for the equilibrium prices and demands in the region of the state space where the constraint is non-binding. We show that, at the equilibrium, stock holdings volatility as well as its ratio to stock price volatility are increasing functions of the stock price and interpret this finding in terms of the price-volume relation. We would like to thank the editor and two anonimous referees for valuable substantive comments. Our gratitude also to Franklin Allen, Kerry Back, Domenico Cuoco, Xavier Freixas, Sanford Grossman, Michel Habib, Lutz Hendricks, Richard Kihlstrom, Fernando Restoy, Mary Thomson, Jean-Luc Vila, participants to seminars at Birkbeck College, Carnegie-Mellon, Columbia, ESSEC, HEC, IAE, INSEAD, London Business School, London School of Economics, McGill, Michigan, National University of Singapore, Pompeu Fabra, North Carolina, Washington-St-Louis, Wharton, the Jornadas de Economía Financiera BBV, and the Meetings of the Society for Economic Dynamics and Control and the American Finance Association. Special thanks are due to Süleyman Basak for his enthusiastic support and many helpful suggestions. The usual disclaimer applies. We gratefully acknowledge the support of the BBV and Caja de Madrid Foundations and CREF (both authors) and of the Spanish Ministry of Education under DGICYT grant no. PB93-0388 (first author).     

Designing social security - a portfolio choice approach

Public social security systems may provide diversification of risks to individuals’ life-time income. Capturing that a pay-as-you-go system (paygo) may be considered as a “quasi-asset”, we study the optimal size of the paygo system as well as the optimal split between funded and unfunded pension saving by means of a theoretical portfolio choice framework. A low-yielding paygo system can benefit individuals if it contributes to hedge other risks to their lifetime resources. Numerical calculations indicate that optimal social security systems should be at least partly paygo financed in many economies. The optimal magnitude of the paygo system depends on the specified risk concept as well as the stochastic properties of stock market returns and implicit paygo-returns.