Parsimonious Model for Predicting Mean Cabinet Duration On the Basis of Electoral System

Abstract

This study joins two existing logical models and tests the resulting predictions of mean cabinet duration (C). One of these models predicts C based on effective number of parties (N): C = k/N2, where k is found to be around 42 years. The other predicts N on the basis of number of seats in the assembly (S) and district magnitude (M). The new combined model leads to a prediction for the mean cabinet duration in terms of these two institutional factors: C = 42 years/(MS)1/3. Three-quarters of the actual mean durations agree with the prediction within a factor of 2. For the purposes of institutional engineering, the model predicts that doubling the district magnitude would reduce the mean cabinet duration by 21 percent ceteris paribus.