Who is the agenda setter? Examining the intermedia agenda-setting effect between Twitter and newspapers

The purpose of this study is to explore the intermedia influence between Twitter's and newspapers' agendas on the topic of climate change. Accordingly, using President Trump's announcement of withdrawing the U.S. from the Paris Agreement as a dividing point, we compare the agendas on Twitter and newspapers before and after the announcement, analyzing rank-order and cross-lagged correlations between both platforms. Results suggest that newspapers influenced Twitter before the announcement, whereas Twitter conversely influenced newspapers within five days after the announcement. However, Twitter's influence was found ephemeral, newspapers regained its unidirectional impact five days after the announcement. The findings imply that Twitter is more likely to influence newspapers' agenda in terms of breaking news, whereas newspapers are more likely to lead Twitter's agenda in terms of ongoing discussions during non-breaking news periods.