A mixed blessing for the left? Early voting, turnout and election outcomes in Norway

•We study the relationship between turnout and election outcomes in Norway.•We rely on an early voting reform to identify exogenous variation in turnout.•Both the social democratic party and a populist right party benefited from the increase in turnout.

Is there a relationship between turnout and election outcomes? Although this is a classic topic in political science, most studies on multiparty systems have important theoretical and empirical shortcomings. First, we argue that the proper implication of the theoretical argument that underpins research on the turnout-vote nexus is that high levels of turnout should typically benefit both traditional social democratic parties and parties of the radical right relative to other types of parties, including not only those of the traditional right, but also ‘left-libertarian’ parties. Second, few have studied the relationship between turnout and election outcomes with a research design that is appropriate for causal inference. In our empirical study, our identification strategy is to exploit a Norwegian reform of early voting rules as an exogenous source of variation in turnout. Our theoretical expectations are largely borne out in our empirical results.