In 1993, Martin Osborne and Al Slivinski developed a model of political competition with citizen-candidates. The model analyzes how citizens decide whether to run for office, considering the costs of entry and the benefits of winning. The study examines both plurality rule and runoff systems, showing how the number of candidates depends on the ratio of the benefits of winning to the costs of entry. Under plurality rule, equilibria can involve one, two, or more candidates, with some candidates guaranteed to lose. The model highlights that under plurality rule, a two-candidate equilibrium is more likely than under a runoff system. The study also shows that under a runoff system, equilibria with multiple candidates taking the same position are possible, and the number of candidates increases as the benefit of winning relative to the cost of entry increases. The model demonstrates that the number of candidates in political competitions varies widely, and that the strategic decisions of citizens and candidates play a significant role in determining the outcomes. The study also considers the implications of different electoral systems on the likelihood of three-candidate equilibria and the behavior of candidates in such scenarios. The model provides insights into the dynamics of political competition and the factors that influence the number of candidates in elections.In 1993, Martin Osborne and Al Slivinski developed a model of political competition with citizen-candidates. The model analyzes how citizens decide whether to run for office, considering the costs of entry and the benefits of winning. The study examines both plurality rule and runoff systems, showing how the number of candidates depends on the ratio of the benefits of winning to the costs of entry. Under plurality rule, equilibria can involve one, two, or more candidates, with some candidates guaranteed to lose. The model highlights that under plurality rule, a two-candidate equilibrium is more likely than under a runoff system. The study also shows that under a runoff system, equilibria with multiple candidates taking the same position are possible, and the number of candidates increases as the benefit of winning relative to the cost of entry increases. The model demonstrates that the number of candidates in political competitions varies widely, and that the strategic decisions of citizens and candidates play a significant role in determining the outcomes. The study also considers the implications of different electoral systems on the likelihood of three-candidate equilibria and the behavior of candidates in such scenarios. The model provides insights into the dynamics of political competition and the factors that influence the number of candidates in elections.