Campaigning and split-ticket voting in new electoral systems: The first MMP elections in New Zealand, Scotland and Wales

New electoral systems create learning problems for parties and electors: the parties have to learn how to focus their campaigns and the electors how best to use their votes. This was the case in three countries in the late 1990s where MMP was used for the first time rather than first-past-the-post: New Zealand in 1996 and Scotland and Wales in 1999. MMP involves each elector voting twice - for a candidate in a single-member constituency contest and for a party in a regional/national list contest. Survey and (in New Zealand) official data show that substantial proportions of the three electorates voted a split ticket - the candidate they supported was from a different party to that they voted for in the list contest. (Approximately one-in-five did this in Scotland and Wales and two-in-five in New Zealand.) We argue that split-ticket voting will be influenced by the amount of information received by electors regarding the candidates for the constituency seats. Using the amount of campaign expenditure by each candidate as a measure of the volume of information provided, we find strong supporting evidence for this responsive voter model in each of the three countries.