Whose morning, whose evening? Temporal asymmetries in intermedia agenda-setting between X and online news in Türkiye

This study examines whether temporal ordering between X and online news varies across first-level issue and second-level attribute agendas in Türkiye's polarized media environment. The analysis draws on 448,664 X posts and 10,357 articles from 19 mainstream online news outlets collected during the 31-day period preceding and including the 31 March 2024 Istanbul local election. Using 12-hour AM/PM windows, we conducted 122 cross-lagged panel analyses-62 same-day AM → PM and 60 overnight PM→next-day AM panels across the two agenda levels-comparing issue- and attribute-indicator frequency profiles. First-level issue agendas were strongly synchronized, with correlations often approaching or exceeding r = .90, whereas second-level attribute relationships were weaker and less consistent. At the first level, morning online news issue salience more often preceded later X issue salience within same-day transitions, whereas evening X issue salience more often preceded the following morning's online news issue salience across overnight transitions. Most first-level cross-lagged correlations exceeded their Rozelle-Campbell (RCb) baselines, while second-level coefficients did so less consistently. These findings indicate that agenda leadership in a hybrid media system is temporally contingent and level-specific rather than static. The observed patterns represent temporally ordered associations and should not be interpreted as evidence of direct causal influence.