Quantifying time-dependent Media Agenda and public opinion by topic modeling

PINTO, SEBASTIÁN; ALBANESE, FEDERICO; BALENZUELA, PABLO

Congreso; StatPhys 27; 2019

The mass media plays a fundamental role in the formation of public opinion, either by defining the topics of discussion or by making an emphasis on certain issues. Directly orindirectly, people get informed by consuming news from the media. Naturally, two questions appear: What are the dynamics of the agenda and how do people become interestedin their different topics? These questions cannot be answered without proper quantitative measures of agenda dynamics and public attention. In this work we study the agenda ofnewspapers in comparison with public interests by performing topic detection over the news. We define Media Agenda as the distribution of topic's coverage by the newspapersand Public Agenda as the distribution of public interest in the same topic space. We measure agenda diversity as a function of time using the Shannon entropy and differencesbetween agendas using the Jensen-Shannon distance. We found that the Public Agenda is less diverse than the Media Agenda, especially when there is a very attractive topic andthe audience naturally focuses only on this one. Finally, using the same methodology we also can detect coverage bias in newspapers.