The case for nil votes : voter behavior under asymmetric information in compulsory and voluntary voting systems

We experimentally study the impact of adding an explicit nil vote option to the ballot in both compulsory and voluntary voting settings. We investigate this issue in an informational voting setting, in which some voters are uninformed and face the swing voter’s curse, implying that they can only affect the expected election outcome adversely. We generate predictions using a simple model of strategic voting in which some voters receive a psychological benefit (along the lines of Riker and Ordeshook (1968)) from choosing an action that they consider a legitimate participation in the election. We test our model in a double-blind pen-and-paper laboratory experiment, and find that the main comparative predictions of the model hold in the data, particularly strongly for compulsory voting. In particular, both under compulsory and voluntary voting, introducing a nil vote option reduces the number of uninformed voters casting a vote for a candidate, increasing voters’ expected welfare. Additionally, it eradicates strategic invalid votes under compulsory voting