Party pressure in the European Parliament

At the end of its sixth legislative term the European Parliament adopted a rule change subjecting all final passage votes on legislative matters to roll call votes. Some studies use this rule change to assess whether roll call votes are characterized by more or less party discipline. Cautioning against such simple comparisons I propose to estimate in this article the extent to which members of the European Parliament are subject to party pressure. Comparing the results from the beginning of the sixth and seventh legislative term shows that in final passage votes the average party pressure has decreased considerably after the rule change.