CAPACITY, DIVERSITY, AND VOLATILITY OF THE PUBLIC AGENDA - TRENDS FROM 1954 TO 1994

This study examined three intertwined hypotheses about long-term trend s in the American public's issue agenda: increases in (1) agenda capac ity, (2) agenda diversity, and (3) issue volatility. These hypotheses were tested with aggregate time series data covering 40 years of Gallu p Poll Most important Problem questions. The first two hypotheses also were replicated with cross-sectional data at the individual level con sisting of 15,000 cases from three different years stretching across 4 decades. While no significant linear increase ill the carrying capaci ty 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 explanatio n that the volatility of contemporary public opinion is the result of a collision between two opposing forces, the expansive influence of ed ucation on awareness of public issues and the constraint imposed by th e public agenda's limited capacity.