Capacity, Diversity, and Volatility of the Public Agenda: Trends From 1954 to 1994

Abstract

This study examined three intertwined hypotheses about long-term trends in the American public's issue agenda: increases in (1) agenda capacity, (2) agenda diversity, and (3) issue volatility. These hypotheses were tested with aggregate time series data covering 40 years of Gallup Poll Most Important Problem questions. The first two hypotheses also were replicated with cross-sectional data at the individual level consisting of 15,000 cases from three different years stretching across 4 decades. While no significant linear increase in the carrying capacity is found, our results provide unambiguously strong evidence for an increase in both agenda diversity and issue volatility. These findings about the public agenda are consistent with the proffered explanation that the volatility of contemporary public opinion is the result of a collision between two opposing forces, the expansive influence of education on awareness of public issues and the constraint imposed by the public agenda's limited capacity.