BES-2006, the second wave of post-electoral research of an academic nature held in Brazil, was inserted in Module 3 (2006-2010) of the Comparative Study of Electoral Systems (CSES) of the University of Michigan, whose central concern was to analyze the scope of the electoral system from the perspective of voters over their choices, the retrospective assessment of parties, candidates, and ideologies. The questions in this module intend to answer specifically how voters distinguish parties, and how contextual conditions increase the degree and convenience with which they can make these distinctions and their relative importance in different contexts. Some results of the BES-2006 are presented in Public Opinion Journal, vol. 13, n. 2 (Oct. 2007).