Social orderings for the assignment of indivisible objects

In the assignment problem of indivisible objects with money, we study social ordering functions which satisfy the requirement that social orderings should be independent of changes in preferences over infeasible bundles. We combine this axiom with efficiency, consistency and equity axioms. Our result is that the only social ordering function satisfying those axioms is the leximin function in money utility.     

On the impossibility of complete Non-Interference in Paretian social judgements

We study a principle of ‘Non-Interference’ in social welfare judgements. Non-Interference captures aspects of liberal approaches (particularly a Millian approach) to social decision making. In its full generality, Non-Interference produces an impossibility result: together with Weak Pareto Optimality, it implies that a social welfare ordering must be dictatorial. However, interesting restricted versions of Non-Interference are compatible with standard social welfare orderings.     

Efficient strategy-proof exchange and minimum consumption guarantees

For exchange economies with classical economic preferences, it is shown that any strategy-proof social choice function that selects Pareto optimal outcomes cannot guarantee everyone a consumption bundle bounded away from the origin. This result demonstrates that there is a fundamental conflict between efficiency and distributional goals in exchange economies if the social choice rule is required to be strategy-proof.     

Nash implementation with partially honest individuals

We investigate the problem of Nash implementation in the presence of “partially honest” individuals. A partially honest player is one who has a strict preference for revealing the true state over lying when truthtelling does not lead to a worse outcome than that which obtains when lying. We show that when there are at least three individuals, all social choice correspondences satisfying No Veto Power can be implemented. If all individuals are partially honest and if the domain is separable, then all social choice functions can be implemented in strictly dominant strategies by a mechanism which does not use “integer/modulo games”. We also provide necessary and sufficient conditions for implementation in the two-person case, and describe some implications of these characterization conditions.     

Evolutionary stability of social norms in a socioeconomic equilibrium model

A hybrid of a model of economic equilibrium in two markets and a social game is formed. The link between the two is established through a social norm that conditions correct social behavior on economic variables and therefore distorts the economic equilibrium allocation. The initial endowment of an individual determines whether she gains from a social norm. The evolution of norms is examined in a dynamic model where norms are more likely to persist if they deliver higher utility to their believers. Also it is assumed that norms lose importance when they are disobeyed by their believers. Optimally coordinating norms are not necessarily evolutionarily stable, and a suboptimal norm can be the outcome of the evolutionary process.     

Democracy,dictatorship, and transformation: A proposal for a constitution-guided systematic change in formerly Soviet republics

A system transformation contains complicated social dilemmas and special-interest problems. Thus it is frequently suggested that democratic decisionmaking is inappropriate for introducing a market economy in the former socialist countries. In this paper I argue that this view rests on a nirvana approach, because it neglects the dynamics of authoritarian governments. It is shown that dictatorships tend to serve even narrower special interests than democracies and are therefore usually less likely to pursue a consistent transformation policy. However, a dictatorship could, under certain cultural and social conditions, have some advantages over democracies. But those conditions are barely present in the formerly socialist countries. Moreover, a dictatorship can by its very nature not be committed and cannot even commit itself to a certain public policy. Hence, there is only one instrument to mitigate social dilemmas in transformation countries: a set of constitutional rules. Some basic properties of a constitutional approach of system transformation are introduced in the last section of the paper.     

An extreme point characterization of random strategy-proof social choice functions: The two alternative case

We show that every strategy-proof random social choice function is a convex combination of strategy-proof deterministic social choice functions in a two-alternative voting model. This completely characterizes all strategy-proof random social choice functions in this setting.     

Factoring out the impossibility of logical aggregation

According to a theorem recently proved in the theory of logical aggregation, any nonconstant social judgment function that satisfies independence of irrelevant alternatives (IIA) is dictatorial. We show that the strong and not very plausible IIA condition can be replaced with a minimal independence assumption plus a Pareto-like condition. This new version of the impossibility theorem likens it to Arrow's and arguably enhances its paradoxical value.     

Arrovian aggregation in economic environments: how much should we know about indifference surfaces?

Arrow's celebrated theorem of social choice shows that the aggregation of individual preferences into a social ordering cannot make the ranking of any pair of alternatives depend only on individual preferences over that pair, unless the fundamental weak Pareto and non-dictatorship principles are violated. In the standard model of division of commodities, we investigate how much information about indifference surfaces is needed to construct social ordering functions satisfying the weak Pareto principle and anonymity. We show that local information such as marginal rates of substitution or the shapes “within the Edgeworth box” is not enough, and knowledge of substantially non-local information is necessary.     

Market competition and firms' social performance

This paper investigates whether market competition encourages firms to be more socially responsible. We find that firms in more competitive markets exhibit better overall social performance, as measured by doing well (“strength”) and doing badly (“concern”) in areas such as community, environment, human rights, and treatment of employees. To deal with endogeneity, we instrument market competition on entry barrier and observe that market competition only significantly reduces social concerns but not increases social strengths. Thus, firms are more reactive in reducing social concerns than proactive in augmenting their social strengths. Amongst these concerns, firms appear to be more active in reducing environmental concerns. The paper underscores the limitations in relying on the “invisible hand” of the market to deal with the multi-dimensional challenges of firms’ social performance.     

Ordinal aggregation and quantiles

Consider the problem of aggregating a profile of interpersonally comparable utilities into a social utility. We require that the units of measurement of utility used for agents is the same as the units of measurement for society (ordinal covariance) and a mild Pareto condition (monotonicity). We provide several representations of such social aggregation operators: a canonical representation, a Choquet expectation representation, a minimax representation, and a quantile representation (with respect to a possibly non-additive set function on the agents). We also isolate an additional condition that gives us a quantile representation with respect to a probability measure, in both the finite and infinite agents case.     

An experimental study on individual choice, social welfare, and social preferences

We experimentally study subjects’ compliance with dominance relationships of income distributions in a ranking task. The experiment consisted of four different treatments: Lottery, individual choice, social preferences, and social planner. Our results suggest that people's risk attitudes do not adequately reflect their inequality attitudes. Uninvolved social planners exhibit randomization preferences, while self-interested social planners are generally more inequality averse and try to avoid extreme outcomes.     

Mechanism design with side payments: Individual rationality and iterative dominance

We investigate the collective decision with incomplete information and side payments. We show that a direct mechanism associated with the social choice function that satisfies budget balancing, incentive compatibility, and interim individual rationality exists for generic prior distributions. We consider the possibility that a risk-averse principal extracts full surplus in agency problems with adverse selection. With regard to generic prior distributions, we show that there exists a modified direct mechanism associated with the virtual social choice function, which satisfies budget balancing and interim individual rationality, such that truth telling is the unique three times iteratively undominated message rule profile.     

Social evaluations when populations differ in size

Assessments of “social welfare” do not usually take into account population sizes. This can lead to serious social evaluation flaws, particularly in contexts in which policies can affect demographic growth. We develop in this paper a little‐known though ethically attractive approach to correcting the flaws of traditional social evaluations, an approach that is sensitive to population sizes and that is based on critical‐level generalized utilitarianism (CLGU). Traditional CLGU is extended by considering arbitrary orders of welfare dominance and ranges of “poverty lines,” as well as values for the “critical level” of how much a life must be minimally worth to contribute to social welfare. We apply these social evaluation methods to rank Canada across 1976, 1986, 1996 and 2006 and to estimate normatively and statistically robust lower and upper bounds of critical levels over which these rankings can be made.     

Do people tip strategically,to improve future service? Theory and evidence

Abstract.  A central question about tipping is whether people tip strategically, to improve future service, or only because tipping is a social norm. I present a theoretical model that incorporates psychological utility associated with tipping (because it is a social norm) and allows tipping to be motivated also by future service considerations. The model predicts that if future service is a reason for tipping, the sensitivity of tips to service quality should be higher for repeating customers than for non-repeating ones. Surveys of 597 restaurant customers are analysed and suggest that future service is not a reason for tipping.     

Licensing to a durable-good duopoly in patent litigation

Incorporating patent litigation into a durable-good duopoly model, we revisit the optimal licensing contract on a cost-reducing innovation. We find that both the optimal licensing contract and the innovator's licensing revenue are closely related to the patent's strength, i.e., the probability it would be found valid if tested in court. It is shown that, for a relatively weak patent (patent's strength is low), it's optimal for the innovator to charge the royalty rate as high as possible coupled with a negative fixed fee. But for a relatively strong patent (patent's strength is high), contract involving the combination of a medium level royalty rate and a positive fixed fee is optimal. We also discuss how the patent's strength affects the social welfare of a patent. Finally we present two policy suggestions that may alleviate the social welfare loss raised by the licensing of weak patents.     

Public goods in networks

This paper considers incentives to provide goods that are non-excludable along social or geographic links. We find, first, that networks can lead to specialization in public good provision. In every social network there is an equilibrium where some individuals contribute and others free ride. In many networks, this extreme is the only outcome. Second, specialization can benefit society as a whole. This outcome arises when contributors are linked, collectively, to many agents. Finally, a new link increases access to public goods, but reduces individual incentives to contribute. Hence, overall welfare can be higher when there are holes in a network.     

On the robustness of laissez-faire

This paper considers a model economy in which agents are privately informed about their type: their endowments of various goods and their preferences over these goods. While preference orderings over observable choices are allowed to be correlated with an agent's private type, we assume that the planner/government is both uncertain about the nature of this joint distribution and unable to choose among multiple equilibria of any given social mechanism. We model the planner/government as having a maxmin objective in the face of this uncertainty.Our main theorem is as follows: Once we allow for this kind of uncertainty and assume no wealth effects in preferences, the uniquely optimal social contract is laissez-faire, in which agents trade in unfettered markets with no government intervention of any kind.     

Household inequality, social welfare, and trade

Working with Sen social welfare functions (meaning explicit separability between mean income and income dispersion), we develop a generalized dual approach to tracking household inequality aspects of social welfare in general equilibrium. We highlight how household equity can be examined analytically alongside production efficiency in duality-based models, using our dual framework to explore potential trade-offs between efficiency and equity effects of trade policy. Our results complement the set of standard inequality results in trade theory focused on functional rather than household inequality. We also find that the relative distributional impact of tariffs on welfare is conditional on the initial level of inequality.     

Imperfect monitoring in communication networks

Individuals in many social networks imperfectly monitor other individuals’ network relationships. This paper shows that, in a model of a communication network, imperfect monitoring leads to the existence of many inefficient equilibria. Reasonable restrictions on actions or on beliefs about others’ actions can, however, eliminate many of these inefficient equilibria even with imperfect monitoring. Star networks, known to be efficient in many settings, are shown to have desirable monitoring characteristics. More generally, this paper provides a formal framework in which to study incorrect perceptions as an equilibrium phenomenon in social networks.