Probabilistic voting model

The probabilistic voting theory, also known as the probabilistic voting model, is a voting theory developed by professors Assar Lindbeck and Jörgen Weibull in the article "Balanced-budget redistribution as the outcome of political competition", published in 1987 in the journal Public Choice, which has gradually replaced the median voter theory, thanks to its ability to find equilibrium within multi-dimensional spaces.

The probabilistic voting model assumes that voters are imperfectly informed about candidates and their platforms. Candidates are also imperfectly informed about the utility preferences of the electorate and the distribution of voters' preferences.

Unlike the median voter theorem, what drives the equilibrium policy is both the number and the density of social groups and not the median position of voters on a preference scale. This difference explains why social groups which have a great homogeneity of preferences are more politically powerful than those whose preferences are dispersed.