Media agenda setting takes time. However, with the evolving media landscape altering how we consume news, many contemporary agenda-setting studies still rely on decade-old guidelines to determine time lags instead of empirically testing them. The literature also reveals inconsistent conceptualizations of “time lag.” To address this, we propose a two-dimensional typology to clarify this concept and conduct a systematic literature review of 1,444 articles published between 1972 and 2024 to trace conceptual and methodological trends of the time lag research, and identify factors influencing time lag length. Results show that, on average, it took 55 days of media exposure (accumulation) for the agenda-setting effect to appear at the aggregated level and 28 days at the individual level, with public response lagging by about 7 days (delay). Additionally, media agenda setting tends to take longer to manifest at higher levels and occur more quickly in collectivist societies compared to individualist ones.
Guo et al. (2026) studied this question.