The institutional foundations of committee cohesion in a (changing) parliamentary democracy

The role played by legislative committees in parliamentary democracies is directly related to some of their properties. In particular cohesion, namely similarity of committee members' preferences, is the most important non-institutional feature that influences committee working. This non-institutional aspect, on its turn, is directly affected by the institutional environment. In this paper we hypothesize that electoral rules, committee agenda setting power and MP's level of knowledge of the committee policy domain influence the committee cohesiveness by affecting the utility that a MP derives from a purposeful choice of the legislative committee she belongs to. To test this proposition we focus on the last 30 years of Italian legislative activity using data from co-sponsorship to infer MPs' preferences in a multidimensional policy space. During this period Italy has experienced drastic changes in its political system. These changeable circumstances give a strong comparative flavor to the present study. Statistical analysis at individual level confirms our hypotheses.