The Effective Length of the Presidential Primary Season

Scholars interested in the speed with which each of the two major US political parties selects its presidential nominee focus on delegate allocation rules and voter preferences as possible sources of variation, but disagree as to the impact of each. I use computer simulations to explore the effects of these two variables. The simulations show that both proportional allocation and more diverse voter preferences increase the number of primaries that must be completed before a single candidate can amass sufficient delegates to guarantee nomination. These findings are consistent with the predictions of existing literature, but previous research generally presents delegate allocation rules and voter preferences as alternative rather than complementary explanations. The results presented here suggest that they have the potential to be complementary.