On the frontier between possibility and impossibility theorems in social choice

This paper attemts to make precise the frontier between possibility and impossibility theorems in social choice. It is shown that some criterion of rejection of some alternative is the critical factor. In the absence of such a condition, it is possible to construct a fairly wide class of “democratic” decision rules which satisfies a class of consistency conditions. Any one of these, together with the criterion of rejection, generates a power structure similar to the ones discovered by Arrow, Gibbard, and others when the decision rule is required to satisfy the weak Pareto principle and the independence condition.     

A characterization of consistent collective choice rules

We characterize a class of collective choice rules such that collective preference relations are consistent. Consistency is a weakening of transitivity and a strengthening of acyclicity requiring that there be no cycles with at least one strict preference, which excludes the possibility of a “money pump.” The properties of collective choice rules used in our characterization are unrestricted domain, strong Pareto, anonymity and neutrality. If there are at most as many individuals as there are alternatives, the axioms provide an alternative characterization of the Pareto rule. If there are more individuals than alternatives, however, further rules become available.     

The structure of strategy-proof social choice — Part I: General characterization and possibility results on median spaces

We define a general notion of single-peaked preferences based on abstract betweenness relations. Special cases are the classical example of single-peaked preferences on a line, the separable preferences on the hypercube, the “multi-dimensionally single-peaked” preferences on the product of lines, but also the unrestricted preference domain. Generalizing and unifying the existing literature, we show that a social choice function is strategy-proof on a sufficiently rich domain of generalized single-peaked preferences if and only if it takes the form of voting by issues (“voting by committees”) satisfying a simple condition called the “Intersection Property.”Based on the Intersection Property, we show that the class of preference domains associated with “median spaces” gives rise to the strongest possibility results; in particular, we show that the existence of strategy-proof social choice rules that are non-dictatorial and neutral requires an underlying median space. A space is a median space if, for every triple of elements, there is a fourth element that is between each pair of the triple; numerous examples are given (some well-known, some novel), and the structure of median spaces and the associated preference domains is analysed.     

Sequentially consistent rules of choice under complete uncertainty

This work analyzes the problem of individual choice under complete uncertainty. In this context, each alternative action consists of a set of different possible outcomes with no associated probability distribution. The work examines and defines a class of rules such that: (a) the evaluation of sets (actions) follows a certain procedural pattern; and (b) an assumption of sequential contraction consistency, which is an adaptation of Sen's α condition, is satisfied. In this framework, some results of characterization show that several well-known rules for comparing sets of outcomes can be reinterpreted in procedural terms.     

ReGale: Some memorable results

This article reviews, with admiration and awe, the scientific contributions of David Gale.     

Trade policy in majoritarian systems: the case of the U.S.

Abstract We provide a theory of trade policy determination that incorporates the protectionist bias inherent in majoritarian systems, suggested by Grossman and Helpman (2005) . The prediction that emerges is that in majoritarian systems, the majority party favours industries located disproportionately in majority districts. We test this prediction using U.S. data on tariffs, Congressional campaign contributions, and industry location in districts represented by the majority party over the period 1989–97. We find evidence of a significant majority bias in trade policy: the benefit to being represented by the majority party appears at least as large in magnitude as the benefit to lobbying.     

东亚汇率协调机制与中国的理性选择

1997年亚洲金融危机之后,汇率协调的重要性已在东亚各国政府及经济学界形成共识.对于如何建立东亚汇率协调机制,许多国家政府和经济学家都提出了解决方案,并进行了大量的实证研究.如东亚日元区方案、东亚美元本位方案、一篮子目标区爬升钉住方案、亚洲汇率机制方案以及编制亚洲货币单位方案等.但是,通过对比分析各种协调方案认为,目前在亚洲还不存在一种可行的稳定的汇率协调机制,因此,谋求人民币在亚洲地区作为关键货币的地位才是中国在东亚货币合作中的最大利益所在.     

On the possibility of welfare-enhancing hard core cartels

The conventional wisdom is that cartels which merely lead to lower production levels and higher prices are detrimental to social welfare. This paper explores the extent to which this is generally valid. We derive necessary and sufficient conditions for the existence of a hard core cartel that is beneficial for firms and society at large. Considering both strong (with side payments) and weak (without side payments) hard core cartel contracts, we find that (i) both strong and weak welfare-enhancing cartels exist when at least one firm makes a loss on part of its sales in competition, (ii) a welfare-enhancing strong cartel exists whenever there is a difference in unit cost at competitive production levels, and (iii) a welfare-enhancing weak cartel exists when the profit margin on all sales is positive and the cost difference is sufficiently large.     

一把插向心脏的刀--论意识形态批判之(不)可能

这篇论文旨在处理这样一个被思想史尘封的问题:今天,意识形态是否可能?通过论述了重新复兴古典哲学的方案,施特劳斯向当代哲人——更广泛的意义上,知识分子——提供了一个系统性的解决方案,来应对在今天的所谓的“后意识形态时代”中的霸权性意识形态(自由主义)。这篇论文批判性地分析了这一施特劳斯主义方案,并揭示了其理论的内核:犬儒主义。通过重新审视哲学史,这篇论文突出了一个以苏格拉底、康德、拉康为代表的“离奇的”传统,这个传统以一个构成性的空无/缺失/不可能性为核心。根据本论文,这一哲学是在后9·11时代,意识形态批判之唯一的(不)可能的实践。     

论人民币成为世界货币的可能性

人民币成为世界货币是对世界范围内的资源进行的一种有利于中国的配置.由于多元世界货币的竞争态势决定了人民币在发展成为世界货币的过程中存在着诸多风险,而规避风险的根本出路在于稳定人民币的币值,提升人民币的国际竞争力.随着我国整体经济实力地不断增强,随着人民币在国际经济活动中参与程度的不断提高,人民币必然朝着世界货币的方向发展.     

Tests of the “convergence hypothesis”: Some further results

The article presents new tests of the convergence hypothesis. It first analyzes the unconditional pattern of growth of human and physical capital (conventionally measured by an inventory method) and shows that these tests do support the hypothesis that domestic inputs of poor countries appear to be catching up with those of rich countries. On the other hand, when one analyzes the pattern of growth of physical capital and Solow residual, then one is led to reject the convergence theory. Building on this discrepancy, I demonstrate that the poor countries have failed to catch up with rich ones because the progress that they have achieved in educating their workers (which is evidenced in the convergence of domestic inputs) is not sufficient to compensate for their poor endowment in the knowledge on which the education of workers stands.     

On the possibility of attaining environmental and trade objectives simultaneously

With the greening of political debate around the world, large nations — precluded from using trade instruments explicitly — have become aware of the fact that they can manipulate their domestic tax structure to attain environmental and trade objectives simultaneously. In this note we show how such nations can attain these two targets with one instrument. Specifically, we show how to construct dual purpose taxes. We then focus on the empirical determinants of these taxes.     

On the determinants of household debt maturity choice

This article jointly analyses a behavioural and a cultural concept to explain household debt portfolio choice. The behavioural approach explores the role of time preferences on household debt maturity in a theoretical model and a numerical analysis. We derive a positive relationship between the long-term discount factor δ and the optimal maturity of household loans. The cultural approach examines whether national culture is a reasonable predictor for household debt maturity. We show that culture is an important factor for households’ borrowing decisions and has even more predictive power than time preferences. Countries with higher scores on the Hofstede dimension of long-term orientation tend to have shorter household debt maturity. Time preferences incur a primarily mediating role, because the effect of national culture on the borrowing decision is reduced, as the long-term discount factor δ increases.     

Locational choice and price competition: some empirical results for the austrian retail gasoline market

Using data from the Austrian retail gasoline market we find that a higher station density reduces average prices. Market (i.e. ownership) concentration does not significantly affect average price, however is negatively related to the density of stations. Estimation of the pricing and entry equations as simultaneous equations does not alter our conclusions, and suggests causality running from station density to price. We argue that the spatial dimension of markets allows the identification of market conduct, which is particularly relevant for competition policy.

Majority voting on tax parameters: Some further results

Earlier analysis of properties of tax functions chosen by majority rule is extended to include more general characterization of individual preferences. Outcomes when preferences are not single-peaked are discussed in some detail.     

A two-period model with portfolio choice: Understanding results from different solution methods

Using a stylized two-period model we compare portfolio solutions from two local solution approaches–the approach of Judd and Guu (2001) and the approach of Devereux and Sutherland (2010, 2011)–with the true nonlinear portfolio solution.     

Retesting positive results in screening for colorectal cancer: a marginal analysis

In the context of screening for colorectal cancer, Neuhauser and Lewecki (1975) have questioned the wisdom of the use of repeated guaiac-based stool tests, arguing that the cost of investigating an asymptomatic population rapidly escalates out of all proportion to the incremental change in the number of cancers detected. This paper addresses a broadly similar problem but makes use of contemporary clinical data from the Nottingham screening trial. Three practicble investigation regimes are evaluated, in terms of the number of cancers detected and the total costs of investigation. It is concluded that, when compared with a regime of direct internal investigation, the appropriate combination of proliminarty guaiac-based stool tests can lead to substantial resource savings at only a small cost in terms of the number of cancers detected.     

On the importance of public choice in migration models

"Recent general equilibrium Tiebout models that use single-crossing indifference curves to establish a migration equilibrium incorporate both voting and migration decisions. These models have concentrated on the important question of the existence of an equilibrium, but the incorporation of both voting and migration has important efficiency consequences as well. This paper demonstrates the important effect of the interaction of voting and migration on efficiency conditions by showing that head taxes (which are generally considered to provide efficient migration incentives with constant marginal congestion costs) do not provide incentives for efficient migration decisions unless the public choice mechanism results in optimal public service provision within jurisdictions."     

The structure of spot rates and immunization: Some further results

This paper estimates and tests a two-factor model of the term structure of interest rates based on the methodology developed by Elton, Gruber and Michaelly (1990) in an APT context. The model is then enlarged to allow its use for interest rate risk measurement through a duration vector. The results of the model using in-sample data are consistent with those obtained by Principal Components Analysis to explain the term structure behaviour. Finally, the model is tested using out-of-sample data, showing its superiority over a competing model based on the traditional Macaulay's duration.