A farewell to IIA

1977

1977

2011

This paper reconsiders the discussion on ordinal utilities versus preference intensities in voting theory. It is shown by way of an example that arguments concerning observability and riskattitudes that have been presented in favour of Arrow's Independence of Irrelevant Alternatives (IIA), and against utilitarian evaluation, fail due to strategic voting. The failure of these two arguments is then used to justify utilitarian evaluation of outcomes in voting. Given a utilitarian viewpoint, it is then argued that strategy-proofness is not normatively acceptable. Social choice theory is criticised not just by showing that some of its most important conditions are not normatively acceptable, but also by showing that the very idea of imposing condition on social choice function under the assumption of sincere behaviour does not make much sense because satisfying a condition does not quarantee that a voting rule actually has the properties that the condition confers to it under sincere behaviour. IIA, the binary intensity IIA, and monotonicity are used as illustrations of this phenomenon.

The Journal of Philosophy, 1981

SSRN Electronic Journal

We describe a model that explains possibly indecisive choice behavior, that is, quasi-choices (choice correspondences that may be empty on some menus). The justification is here provided by a proportion of ballots, which are quasichoices rationalizable by an arbitrary binary relation. We call a quasi-choice s-majoritarian if all options selected from a menu are endorsed by a share of ballots larger than s. We prove that all forms of majoritarianism are equivalent to a well-known behavioral property, namely Chernoff axiom. Then we focus on two paradigms of majoritarianism, whereby either a simple majority of ballots justifies a quasi-choice, or the endorsement by a single ballot suffices-a liberal justification. These benchmark explanations typically require a different minimum number of ballots. We determine the asymptotic minimum size of a liberal justification. a The authors are grateful to Davide Carpentiere for several insightful comments. José Carlos R. Alcantud thanks the audience of The Saarland Workshop in Economic Theory for their suggestions. Alfio Giarlotta gratefully acknowledges the financial support of "Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR)-PRIN 2017", project Multiple Criteria Decision Analysis and Multiple Criteria Decision Theory, grant 2017CY2NCA.

This paper deals with what I identify as a limitation in linear and ordinal modes of analysis for social and moral behavior. Most of the literature on moral and political philosophy produced in the Anglo-Saxon world since the publication of A Theory of Justice has taken the premises of a ordinal account for preferences and values for granted. My hypothesis is that such premises, though methodologically sound, suffer from a practical standpoint as they take as the model of political and social choice a choice “without prejudice”. I will defend that liberal accounts of preference would benefit in taking a more mitigated and ambivalent understanding of preferences, one that admits a) that our thought process regarding the constitution of preferences is linear and somehow passive and b) that the notion of unbiased, unmitigated, position of analysis is ultimately artificial and will not help our understanding of the way actual persons are actually choosing goods

Philosophical Studies, 2016

The independence of irrelevant alternatives (IIA) is a popular and important axiom of decision theory. It states, roughly, that one’s choice from a set of options should not be influenced by the addition or removal of further, unchosen options. Over recent debates, a number of authors have given putative counterexamples to it, involving intuitively rational agents who violate IIA. Generally speaking, however, these counterexamples do not tend to move IIA’s proponents. Their strategy tends to be to individuate the options that the agent faces differently, so that the case no longer counts as a violation of IIA. In this paper, we examine whether this strategy succeeds. We argue that the ways of individuating options required to save IIA from the most problematic counterexamples – in particular, cases where agents violate IIA due to nonconsequentialist moral beliefs – do so only at the expense of severely compromising its central function within decision theory.

This paper generalises Enelow (J Polit 43(4):1062–1089, 1981) and Lehtinen’s (Theory Decis 63(1):1–40, 2007b) model of strategic voting under amendment agendas by allowing any number of alternatives and any voting order. The generalisation enables studying utilitarian efficiencies in an incomplete information model with a large number of alternatives. Furthermore, it allows for studying how strategic voting affects path-dependence. Strategic voting increases utilitarian efficiency also when there are more than three alternatives. The existence of a Condorcet winner does not guarantee path-independence if the voters engage in strategic voting under incomplete information. A criterion for evaluating path-dependence, the degree of path-dependence, is proposed, and the generalised model is used to study how strategic voting affects it. When there is a Condorcet winner, strategic voting inevitably increases the degree of path-dependence, but when there is no Condorcet winner, strategic voting decreases path-dependence. Computer simulations show, however, that on average it increases the degree of path-dependence.

Public choice theory is of considerable significance to the discipline of public policy. Often a subject studied by economists and political scientists, public choice utilizes traditional economic theory to comprehend political behavior. McLean (1991) stated, “public choice is not a subject; it is a way of studying a subject” (p. 1), signifying the application of economic tools, such as rational choice theory, to understand politics. While there has been debate concerning methods and topics taught in graduate public policy programs (Morçöl & Ivanova, 2010), public choice is a subject that is often disregarded outside of the economics and political science disciplines (Pincione, 2004). However, Altman (2012) showed how bounded rationality and behavioral economics have significant applications to public policy, and Pincione (2004) claimed that it is “highly advisable” to teach public choice in other disciplines while it “need not be predictively accurate” (p. 469). This article will demarcate some of the principal concepts of public choice theory and historical foundations related to governments and elections. An in-depth analysis of Kenneth Arrow’s impossibility theorem will follow, since voting and preference aggregation are the most crucial takeaways for the public policy discipline. Overall, public choice and Arrow’s impossibility theorem should be increasingly incorporated into the study of public policy as a way to better understand political motivation, plurality voting, and policymaking.

William Riker famously argued that Arrow's impossibility theorem undermined the logical foundations of " populism ", the view that in a democracy, laws and policies ought to express "the will of the people". In response, his critics have questioned the use of Arrow's theorem on the grounds that not all configurations of preferences are likely to occur in practice. The critics allege, in particular, that majority preference cycles, whose possibility the theorem exploits, rarely happen. In this essay, I argue that the critics' rejoinder to Riker misses the mark even if its factual claim about preferences is correct: Arrow's theorem and related results threaten the populist's principle of democratic legitimacy even if majority preference cycles never occur. In this particular context, the assumption of an unrestricted domain is justified irrespective of the preferences citizens are likely to have.