Determinants of disproportionality and wasted votes

The aim of this article is to explain differences in disproportionality. The dependent variable has two components. One is the index of disproportionality created by Michael Gallagher (1991). The other component consists of the amount of wasted votes, i.e. votes that are given to representatives of parties which fail to gain representation in parliament. Three independent variables are used: district magnitude, electoral thresholds, and the combined measurement of these variables, namely the effective threshold. The test reveals that while Gallagher's index of disproportionality is affected by district magnitude and the effective threshold, the amount of wasted votes remains, with the possible exception of a weak link to electoral thresholds, unaffected by changes in the independent variables. Explanations for the findings are introduced and discussed.