Theoretical Thresholds in List Systems of Proportional Representation

Theoretical thresholds aim at answering the question, how strong the support of a political party has to be in order to win at least one seat. The article proposes general formulas for theoretical thresholds for proportional representation at the district level. The goal of their formulation is to refer to the consistent logic of their derivation. Furthermore, this study also compares particular proportional techniques. None of the the three most recognized methods have theoretical thresholds less hospitable to small parties than the d’Hondt method. The least accommodating to a small party are the Imperiali and Modified d’Hondt methods. From a nationwide perspective, more distinct differences were found only in the case of upper thresholds since the differences between lower thresholds are distinctively eliminated with the increasing number of districts. The final analysis of the current electoral system for the Czech Parliment’s Chamber of Deputies showed that it can significantly disadvantage parties with less than 8 percent of the votes.