On the positive association of parliamentary social choice functions

Intuitively, a voting rule satisfies the condition of positive association if it guarantees that an improvement for an alternative in the preferences expressed by voters results in a change, if there is any, of the social status of that alternative in the same direction. In this article, we consider two interpretations of this notion, and for parliamentary voting procedures, we provide results showing under the impartial anonymous culture (IAC) hypothesis how often the positive association is (not) satisfied. Furthermore, our analysis also permits us to investigate the relationships between these notions.