Primary Effect in Open-List Elections

We study how political parties select political leaders. Using regression discontinuity design and data from Finnish local elections, we find that parties use vote ranks to decide upon promotions. Moreover, we show that this primary effect is higher when competition either between or within parties is lower. We document differences in promotion patterns between parties, the primary effect being stronger in right-wing parties. This result is in line with previous research arguing that right-wing parties prefer more inclusive nomination procedures. Finally, our descriptive analysis suggests that parties weight previous political experience and candidates' policy positions in their promotion decisions more than voters value these characteristics.