Strategic voting in proportional representation systems: Evidence from a natural experiment

Relying on data from a natural experiment in Spain, I produce an unbiased estimate of the extent to which strategic voting occurs in multi-member districts. I show that voters have fully adapted to the different incentives provided by distinctive electoral systems in Spain since the first election and also that they behave strategically only when the opportunity to do so is present. That is, contamination effects do not seem to exist when voting strategically.