We discuss a binomial mixture model for estimating the probability of a political representative acting as a delegate   or a trustee. The model also returns the probability of congruence of a representative with the national median voter. The estimated probability of congruence strongly correlates with the observed frequency of congruence, which was obtained by matching parliamentary roll-call votes with the will of the median voter revealed in Swiss national referendums on identical legislative proposals. Since our method uses the roll-call votes of political representatives as sole input, it can be used to infer congruence levels of politicians, even if the will of the median voter is unobserved

  The slides summarize the main results of my research in collaboration with others on the Condorcet Jury Theorem   and voting power for correlated votes