Cohesion and Candidate Selection in Parliamentary Groups

Previous literature has argued that MPs selected by party elites in a central and exclusiveway aremore disciplined than those belonging to parties withmore inclu-sive and participative mechanisms of candidate selection. This hypothesis has been usually tested measuring the existence of voting blocs in parliamentary groups (taking for granted that voting blocs are the result of party discipline) and party rules on candidate selection (ignoring how selection process takes place). By using data from a survey of a representative sample of Spanish members of par-liaments,we study the impactof candidate selectiononhowcohesion inparliamen-tary groups is built. Results showthatwherenomination for theelectoral list restson party elites, decisions are imposed through discipline. By contrast, parliamentary group cohesion is achieved through deliberative processes of decision-making in more decentralised and inclusive groups. Cohesion in parliamentary groups is a crucial element for political stability in parliamentary democracies, government and legislative efficiency, and for govern-ments ’ accountability (Carey, 2007; Field and Siavelis, 2008). Parliamentary group