Answer:
Agenda-setting research is concerned with the influence of the media on the public's perception of what issues are important or worthy of attention. One key aspect of this research is establishing the existence of a delayed relationship between media agenda and public opinion or agenda. This means that there is a lag between the time when the media focuses on an issue and the time when the public begins to consider that issue to be important.
Establishing the presence of a delay through empirical research can be done through a variety of methods. One way to do this is through the use of panel or longitudinal studies, in which the media diet and opinion of a group of individuals are tracked over time. By examining changes in media consumption and opinion over time, researchers can identify any lag between media coverage and changes in public opinion.
Another way to establish a delayed relationship is through the use of experiments, in which individuals are exposed to different levels of media coverage of an issue and their subsequent opinions are measured. By manipulating the amount of media coverage that participants are exposed to and measuring the resulting changes in opinion, researchers can determine whether there is a delay between media coverage and public opinion.
Overall, the distinction between media agenda and public opinion/agenda is important because it helps to identify the extent to which the media shapes public perception and to understand the mechanisms through which this influence occurs. Understanding these dynamics is important for a variety of reasons, including for policymakers who are interested in understanding how public opinion may be influenced by the media and for media organizations themselves, who may be interested in understanding the impact of their coverage on public opinion.