What do indices of disproportionality actually measure? They provide an aggregate estimation of the difference between votes cast and seats assignment, but the relation between the value of the indices and the will of the voters is highly questionable. The reason is that when casting the vote...

According to commonsense wisdom, under proportionality a small centrist party enjoys an excess of power with reference to its share of seats (or votes) due to the possibility of blackmailing the larger ones. This hypothesis has been challenged on a theoretical ground, with some empirical...