Using cluster analysis to determine the media agenda

This paper describes a software tool that aids researchers in the study of agenda setting. Agenda setting theory claims that the mass media influences what the public thinks and talks about. The tool is used to cluster documents into topically coherent groupings that are to represent issues dominating press coverage. The documents are taken from the archives of online newspapers. In addition, the tool enables results to be visualised and displayed. Three methods were investigated for the purpose of clustering, of which the Group-Average-Linkage algorithm was chosen for the final testing. The choice of the clustering algorithm was predominantly made upon the quality of clusters produced. Comparisons between the computer-based results and a method involving human readers revealed comparable findings and potential usefulness of the software.