Quantifying Parliamentary Representation of Constituents' Preferences with Quasi-Experimental Data

We assess the effect of constituents’ preferences on legislators’ decisions within a quasiexperimental setting: In the Swiss referendum process, citizens and legislators reveal their preferences for legislative proposals. We match roll call votes of all Swiss legislators on 102 legislative proposals with revealed constituents’ preferences on exactly the same issues from 1996 to 2008. The setting allows us to quantify the quality of parliamentary representation and we identify conditions which affect convergence between constituents’ preferences and legislators’ decisions. Results show that a legislator’s probability to accept a law proposal increases by 16.8 percentage points when district voters accept the proposal.