Mapping the agenda-setting theory, priming and the spiral of silence in Twitter accounts of political parties

This paper presents the results of a content analysis of the official Twitter accounts of the main Spanish political parties (Partido Popular, Partido Socialista Obrero Español, Podemos, Ciudadanos and Izquierda Unida) carried out for the period of the 2015 Spanish general election. Compositional biplots are used for data visualisation. Unlike traditional approaches, compositional analysis in general, and the biplot in particular, emphasise the relative salience of issues within the agenda. This analysis sheds light on the agenda-setting theory and closely-related phenomena such as priming (based on associative-activation among a group of issues that are more influential than others) and the spiral of silence (the issues derived from the hierarchy process of agenda-setting that are omitted just after the election day).