## Estimating the Probability of Acting as a Trustee (with D.Stadelmann)

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.