The Political Reliability of Italian Governments: An Exponential Survival Model

Abstract

Italian cabinets (governi) fall from power in a seemingly haphazard pattern, thus defying most deterministic analyses of their durability. This analysis views Italian government longevity as essentially indeterminate, or stochastic, and it applies the theory of “political reliability” to explain the probability that an Italian government will be in power at time t after it was formed. An exponential survival model R = e−kt, with constant government breakdown rate k = .021 per week, is developed, estimated, tested, and discussed. It is shown that Italian governments have a half-life (τ) of approximately 32.8 weeks, after which their political reliability drops below .50, and their mean duration is 47.7 weeks, so the probability that an Italian government will survive as long as the average is only 36.8%. Theoretical aspects of the model are also discussed, together with characteristic features of exponential political reliability, such as lifetime density, political mortality, and government downfall rate, as well as the systems reliability and crisis process characteristic of Italian governments.