Rainy day politics. An instrumental variables approach to the effect of parties on political outcomes

Scholars have grappled with the question of how parties affect policy. Here I propose and test an instrumental variable approach using rainfall. In Norwegian municipal elections, potential left wing voters are likely to abstain from voting with election day rain, whereas the opposite holds for right-wingers. Then rainfall provides an exogenous source of variation, and hence an instrument, for the party composition of the municipal council. A strengthening of the right wing parties due to rainfall shifts expenditures toward education, but reduces total spending. This also shows that political competition does not drive party platforms to converge.