The Tasmanian electorate of Denison at the 2010 Federal Election is an interesting case study of preferential voting in action.
The seat had been held by the ALP since 1987, although the sitting member, Duncan Kerr, retired at the election. The Labor, Liberal and Greens candidates were joined by a candidate from the Socialist Alliance and an independent, Andrew Wilkie.
The image below shows that Wilkie came third on primary votes, behind the Labor and Liberal candidates. The Greens were in fourth place and the Socialist Alliance in fifth. No candidate had an absolute majority of 50% + 1. This meant that preferences had to be distributed until someone secured 50% + 1.
Because she had the lowest number of votes, the Socialist Alliance candidate was excluded first. The allocation of her preferences did not change the order: the ALP still led, the Liberals were second and Wilkie remained in third place.