How the news media activate public expression and influence national agendas

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Science  10 Nov 2017:
Vol. 358, Issue 6364, pp. 776-780
DOI: 10.1126/science.aao1100

Measuring the impact of the media

The active participation of the people is one of the central components of a functioning democracy. King et al. performed a real-world randomized experiment in the United States to understand the causal effect of news stories on increasing public discussion of a specific topic (see the Policy Forum by Gentzkow). Social media posts increased by almost 20% the first day after the publication of news stories on a wide range of topics. Furthermore, the posts were relatively evenly distributed across political affiliation, gender, and region of the United States.

Science, this issue p. 776; see also p. 726


We demonstrate that exposure to the news media causes Americans to take public stands on specific issues, join national policy conversations, and express themselves publicly—all key components of democratic politics—more often than they would otherwise. After recruiting 48 mostly small media outlets, we chose groups of these outlets to write and publish articles on subjects we approved, on dates we randomly assigned. We estimated the causal effect on proximal measures, such as website pageviews and Twitter discussion of the articles’ specific subjects, and distal ones, such as national Twitter conversation in broad policy areas. Our intervention increased discussion in each broad policy area by ~62.7% (relative to a day’s volume), accounting for 13,166 additional posts over the treatment week, with similar effects across population subgroups.

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