What Role for the Party Group Leader? : a Latent Variable Approach to Leadership Effects on Party Group Cohesion in the European Parliament

Abstract

Previous research has identified several structural and situational factors that affect party cohesion in parliamentary voting behaviour. The potential role of leadership has been neglected so far. The authors apply a latent variable approach to model leadership effects in roll call votes from the European Parliament (EP), 1979-2001. Other things being equal, their findings suggest that a small but significant 7 per cent share of the total variance in party group cohesion is due to the party group leaders. About 40 per cent of this leader component can be accounted for by their experience inside the European institutions, their career prospects, and their ideological positions.