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	Probabilistic Voting Model	Public Choice Analysis
Field	Political Economy	Political Economy
Family	MCDM	MCDM
Year of origin	1987	1962
Originator	Assar Lindbeck, Jörgen Weibull & Peter Coughlin	James M. Buchanan & Gordon Tullock
Type	Formal model of electoral competition	Formal framework for collective decision-making
Seminal source	Lindbeck, A., & Weibull, J. W. (1987). Balanced-budget redistribution as the outcome of political competition. Public Choice, 52(3), 273-297.	Buchanan, J. M., & Tullock, G. (1962). The Calculus of Consent: Logical Foundations of Constitutional Democracy. University of Michigan Press. ISBN: 9780865972186
Aliases	Probabilistic Voting Theory, Lindbeck-Weibull Model, Coughlin Probabilistic Voting Model, Stochastic Voting Model	Public Choice Theory, Economics of Politics, Constitutional Political Economy, Virginia School Public Choice
Related	4	4
Summary	The probabilistic voting model is a formal theory of electoral competition in which each voter's choice between two parties is treated as stochastic rather than deterministic, governed by a smooth probability that depends on the policy utilities the parties offer plus idiosyncratic and partisan preference shocks. Developed by Assar Lindbeck and Jörgen Weibull in 1987 and given its general treatment by Peter Coughlin in 1992, the model replaces the knife-edge switching of the median voter framework with continuous vote-share functions. Two office-seeking parties maximize expected vote share, and the resulting equilibrium maximizes a density-weighted social welfare function in which the most responsive — the swing — voters carry the greatest weight. Crucially, the model delivers a determinate, interior equilibrium even in multidimensional policy spaces where a Condorcet winner generically fails to exist.	Public choice analysis is the application of the methods of economics — methodological individualism, rational self-interest, and equilibrium reasoning — to the study of political and collective decision-making. Pioneered by James M. Buchanan and Gordon Tullock in their 1962 book The Calculus of Consent and surveyed comprehensively in Dennis Mueller's Public Choice III, it treats voters, politicians, bureaucrats, and interest groups not as benevolent servants of the public interest but as utility-maximizing agents pursuing their own goals within political institutions. A central methodological move is the distinction between constitutional choice — the selection of the rules of the game behind a veil of uncertainty — and in-period choice within those rules. The framework's signature derivation is the optimal decision rule (the optimal majority), found by minimizing the sum of the external costs a rule imposes and the costs of reaching agreement under it.