Why do parties decide to give attention to some policy issues in detriment of others? Notwithstanding its centrality to political life, this is still an understudied topic. This paper addresses this topic by comparatively analyzing the influence of three level agendas in parties' policy attention in manifestos: the media, the public opinion and the political agenda. This comprehensive and ground-breaking approach allows to study the importance of these agendas controlling for party type and party competition, characteristics that have been neglected in previous research. The analysis relies on an extensive longitudinal database of the Portuguese Policy Agendas Project that includes datasets on media attention, voters' preferences, parliamentary questions and electoral manifestos, between 1995 and 2015, and also interviews with political actors.

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