In coalition governments, parties need to agree on a common policy position. Whose preferences prevail? The proportionality hypothesis, the idea that coalition partners’ influence on policy is proportional to their share of seats, has been used widely in the literature on democratic representation, ideological congruence, and coalition politics. In my analysis of competing theories aimed at determining what influences policy compromise in multiparty governments, I reject the proportionality hypothesis. My results suggest instead that coalition partners exert equal influence on policy compromises, independent of their number of seats. More extensive analysis also provides evidence for increased party influence on policies when the party is the formateur or closer to the parliamentary median, ceteris paribus. As a by-product of my analysis, I provide a simple and better proxy for measuring a government's position when this position is not directly observable.
