Coalition agreements make easy and clear reciprocal relationships between political parties at the same time they set in advance expectations of each coalition’s member. This paper defends that coalitional agreements help stability of government increasing mutual allocations of benefits. From a first theoretical approach to coalitional agreements structure this research analyses the influence on government’s stability in three Spanish Autonomous Communities (Andalusia, Catalonia and Basque Country) during the last two legislatures. The Data Base of the Government Coalitions Observatory (University of Barcelona) allows empirical and qualitative analysis to demonstrate our hypothesis.
