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This paper estimates the private returns to human capital in Pakistani rural labour markets. The rich data used permit inclusion of several dimensions of human capital and control for endogeneity resulting from investment in human capital. The results suggest that, without data on determinants of human capital, it would not be possible to disentangle the separate effect of each dimension of human capital on wage differentials nor to distinguish human capital explanations for wage differentials from signalling and credentialist models. With control for endogeneity of human capital and selectivity into wage employment, cognitive achievement, but not schooling attainment separate from cognitive achievement nor long-run health status, affects wage differentials.  相似文献   
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A firm employs suppliers who make specific investments. Because output demand is uncertain and the cost of enumerating contingencies high, the firm retains some unilateral control over the input quantities it purchases. To allay suppliers’ concerns over potential opportunism the firm must commit not to pit them against one another ex post by threatening to buy less from those who refuse to discount their prices. By extending most-favored treatment guarantees the firm commits not to discriminate. In some circumstances this generates efficient and opportunism-free outcomes. In others it is less effective but may remain attractive relative to other options. Evidence from field market contracts for natural gas corroborates this nondiscrimination hypothesis.  相似文献   
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Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available. Received: August 8, 2000; revised version: January 8, 2001  相似文献   
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An algebraic theory of portfolio allocation   总被引:1,自引:0,他引:1  
Summary. Using group and majorization theory, we explore what can be established about allocation of funds among assets when asymmetries in the returns vector are carefully controlled. The key insight is that preferences over allocations can be partially ordered via majorized convex hulls that have been generated by a permutation group. Group transitivity suffices to ensure complete portfolio diversification. Point-wise stabilizer subgroups admit sectoral separability in fund allocations. We also bound the admissible allocation vector by a set of linear constraints the coefficients of which are determined by group operations on location and scale asymmetries in the rate of returns vector. For a distribution that is symmetric under a reflection group, the linear constraints may be further strengthened whenever there exists an hyperplane that separates convex sets. Received: May 15, 2001; revised version: March 20, 2002 RID="*" ID="*" Journal paper No. J-19797 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 3463, and supported by Hatch Act and State of Iowa funds. Correspondence to: D. A. Hennessy  相似文献   
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Do international labor flows influence the prospects for democratization both in the countries that export their excess workers and in the countries that import them? This paper argues that emigration should have a positive effect on political liberalization in net source countries because it decreases the amount of redistribution that would occur in a more democratic regime. Conversely, immigration should have a negative effect on political liberalization in net destination countries through the same causal channel: by increasing the amount of redistribution that would occur in a more democratic regime. South Korea and Singapore are considered as illustrative examples, and the paper provides statistical evidence to support the hypothesis that emigration (immigration) has been positively (negatively) related to future political liberalization.  相似文献   
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This paper presents a mathematical model to study the joint impact of organizational design and of the task environment on the decision performance of hierarchical organizations with limited internal communication. The problem context is a special class of distributed situation assessment problems, where possible patterns of binary variables are to be classified on the basis of partial and noise-corrupted information. Structural properties of tasks and organizations are described using a graph formalism, and optimal decision strategies at all decision makers are determined. Organizational expertise is characterized in the form of a Team Relative Operating Characteristic (TROC) curve, thereby replacing the organization by an equivalent single decision maker. Implementing the model, issues of task decomposition and the process of matching organizations with tasks are discussed.  相似文献   
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