A secondary analysis of the "1987 Australian Election Study" examined differences in levels of partisanship, political interest, campaign media use, and the importance voters attach to media use, for voters who make up their minds during and before the campaign. Results suggest that voters who make their choice during the campaign are more likely to be swayed by the candidates use of the media than voters who decided before the campaign began. While undecided voters tend to use the media as a source of information about the parties, candidates, and issues, strong partisans use the media because they are interested in politics. In addition, voters who are strongly partisan and interested in politics are not only more likely to make an early choice, but to attach importance to their choice. (Nine tables of data and 11 references are included.) (PRA)