WICKEDNESS IN SOCIAL CHOICE

In an article from 1973, Rittel and Webber distinguished between ‘tame’ or ‘benign’ problems on the one hand and ‘wicked’ problems on the other. The authors argued that wicked problems occur in nearly all public policy issues. Since different groups adhere to different value-sets, solutions can only be expressed as better or worse. By no means can they be viewed as definitive or objective. In this paper we consider, from this very angle, the theory of social choice which is about the aggregation of individual preferences with the aim to derive a consistent social preference. We show that collective choice offers wicked problems of various types which differ in their degree of severity. We hereby concentrate on welfare functions and voting schemes of different kinds and discuss these in the light of various criteria such as Arrow's independence condition, Condorcet consistency, monotonicity, manipulability, and other properties.     

Monotonicity in asset returns: New tests with applications to the term structure,the CAPM,and portfolio sorts

Many theories in finance imply monotonic patterns in expected returns and other financial variables. The liquidity preference hypothesis predicts higher expected returns for bonds with longer times to maturity; the Capital Asset Pricing Model (CAPM) implies higher expected returns for stocks with higher betas; and standard asset pricing models imply that the pricing kernel is declining in market returns. The full set of implications of monotonicity is generally not exploited in empirical work, however. This paper proposes new and simple ways to test for monotonicity in financial variables and compares the proposed tests with extant alternatives such as t-tests, Bonferroni bounds, and multivariate inequality tests through empirical applications and simulations.     

Qualitative valuation of environmental criteria through a group consensus based on stochastic dominance

This paper introduces a qualitative valuation method to elicit stakeholders' intensities of preferences for a complex environmental issue and multiple social groups. Environmental valuation studies have shown that in any complex environment with a diversity of environmental services, stakeholders have difficulties using a monetary valuation to make trade-offs between different environmental services. Stated preference methods such as the Contingent Valuation Method (CVM) have been criticised for their individualistic format and assumptions of commensurability between environmental criteria. To alleviate both of these criticisms, we propose a qualitative valuation method. The method contains a discursive step to allow stakeholders to discuss and construct a list of environmental criteria and alternative plans. The list of criteria and plans is subsequently used by a group of experts to formulate an Impact Matrix (IM), which is to be used in the succeeding individualistic steps of the methodology. The first individualistic step consists of asking the stakeholders to rank Alternative Impacts (AIs) in the IM for each single criterion. The stakeholders are then asked to express intensities of their preferences through pairwise comparisons between the AIs of the constructed rank order on each single criterion. These intensities are expressed on a qualitative scale. Subsequently, to provide social intensities of preferences, a social preference (social rank order) is first determined for each single criterion. We propose to use the median value among the intensities of preferences as the social intensity of preference by assuming interpersonal comparability and taking into account stochastic monotonocity. This is a pre-processing step, which allows us to reach social intensities of preferences in the Lar rangeland (Iran), where several social groups have conflicting interests on rangeland services, leading to conflicting preferences on environmental criteria.     

Some corrections to claims about the literature in Engl and Scotchmer (1996)

Some assertions in Engl and Scotchmer [J. Math. Econ. 26 (1996) 209] concerning prior literature are corrected. In addition, I discuss the differences between the convergence results of Engl and Scotchmer [J. Math. Econ. 26 (1996) 209], and those of this author, alone and with Martin Shubik, dating from 1980. Our prior and concurrent results show that (approximate) -cores of games with many players treat most similar players nearly equally; that is, approximate cores of large games have the equal treatment property. The convergence result of Engl and Scotchmer shows that, in per capita terms, -core payoffs to sufficiently large groups of players can be approximated by equal-treatment payoffs.     

Unsettling aspects of voting theory

Summary. Voting procedures are known to be plagued with a variety of difficulties such as strategic voting, or where a voter is rewarded with a better election outcome by not voting, or where a winning candidate can lose by receiving more support. Once we know that these problems can occur, the next objective should be to completely understand how, why, and where they arise. Namely, for each election procedure, the new goal is to determine when such problems can occur, all voter types who can cause these difficulties, and the actions they must take. This paper develops an easily used approach to handle all of these issues for standard voting methods. New intuitive explanations for these various oddities follow from this approach. Received: August 14, 2002 ; revised version: September 4, 2002 RID="*" ID="*"My thanks to Richard Barrett and, in particular, to Hannu Nurmi for corrections, several useful comments, and suggestions they made about earlier versions. Also, my thanks to a referee for calling some excellent references to my attention. An earlier draft was presented at the 2002 Public Choice Society meeting. This research was supported by an NSF grant.     

New characterizations of a classical bankruptcy rule

Concede-and-divide is a well-known and widely accepted procedure to solve bankruptcy situations involving two agents. In a recent paper, Moreno-Ternero and Villar (2004) characterize it by means of a new property, called securement, that imposes a lower bound on the awards agents might obtain. This property can be naturally decomposed in two more elementary ones. We show that each of these components, together with a suitable version of monotonicity and the standard property of self-duality, also characterize concede-and-divide. We also show that one of these components characterizes the rule, when combined with the standard property of minimal rights first.     

Comparing optimal choices with multi-dimensional action spaces

This paper introduces ordinal conditions on payoff functions for models with multi-dimensional action spaces which guarantee that the optimal action in one direction is greater than the optimal action in another direction at an optimum. Examples are given to motivate these conditions.     

Is Giffen behaviour compatible with the axioms of consumer theory?

A family of direct utility functions is constructed which exhibit the characteristic of Giffenity, while satisfying the axioms of convexity and monotonicity. The approach starts by specifying a price offer curve, C₀, with a required backward-bending segment. Then a set of convex indifference curves is constructed having price offer curve arbitrarily close to C₀.