Setting the Public Agenda

Issue Salience

For those of you interested in the development of academic theories of communication and how they relate to the ongoing public debate, consider this article a primer for an example of one such theory. 

Agenda setting is a theory of the ability to influence the salience of topics on the public agenda. This salience is the initial stage in the formation of public opinion. However, the media do not reflect reality, they merely filter and shape it for the public, according to studies done by the University of Twente, as well as other academic organizations. Usually, this is done by focusing on the entire set of items that define the complete list or plan of action. Alternately, this is done by focusing attention on a single item on the complete list or plan of action. Clearly, then, there is a bit of leeway in how exactly public opinion is formed.

The researchers McCombs and Shaw focused on two elements of issue salience in their study of the 1968 presidential campagin in the United States. These two elements were awareness and information. The function of the mass media was explored, and the two researchers sought to determine the relationship between the content of media messages such as campaign ads and what voters in a single community voiced as important issues. Since there was a strong positive correlation between the substantive content of the media messages and the issues voiced by the community members as important, McCombs and Shaw concluded that the mass mainstream media had a very strong influence on what voters considered to be the major issues of the presidential campaign.


Since 1972, more than 425 empirical studies on this particular theory have been conducted. These have provided detail about time-order and causal links between the media and agenda setting in areas of politics, civil rights, and entertainment. More importantly, studies involving controlled laboratory experiments have been effective in gathering evidence that the news media causes agenda setting effects. Studies demonstrate this through random assignment of subjects to various versions of systematic manipulation of salient issues such as pollution and defense preparedness.

Major Concepts of the Theory

There are several major concepts for this theory, having to do with the elements of issue salience and selective perception.

  1. The main concept of this theory is the transfer of issue salience as information about a few issues. Also discussed is how relative salience of issues is communicated by the media, and the result that the public is led to believe that these issues with stronger salience are more important than other issues. Audiences also perceive issues on a scale of obtrusive to unobtrusive.

  2. Selective perception is used to explain minimal media effects or an absence of agenda setting effects. It locates central influence within the individual.

  3. Awareness of issues is created in the public by media through an agenda-setting process.

  4. The unit of analysis on an agenda is an object, usually a public issue.

  5. Attributes of objects have a cognitive component regarding substantive characteristics and an affective component regarding emotional valences towards the object.

This communication theory also describes the phenomena of transfer of issue salience through first-level and second-level agenda setting effects. Second-level agenda setting effects are dependent on there first being the presence of first-level agenda setting, or the amount of actual coverage of an issue by the media. Cognitive and affective components are examples of second-level agenda setting, and these second-level components are hypothesized to have greater effects than first-level agenda setting. Both first-level and second-level agenda setting effects are also contingent on an audience’s need for orientation in forming perceptions about new or unfamiliar issues and attributes. A need for orientation is informed by the relevance and uncertainty surrounding an issue. This may also impact how obtrusive or unobtrusive a member of the audience finds a particular issue on the agenda.

Strengths and Weaknesses of the Theory

Openness and Parsimony

There are several strengths and weaknesses associated with this communication theory, and in some cases the strength and weakness is the same thing. For example, the openness of the agenda setting theory is a strength, as the theory has been reinterpreted to set the media agenda as a dependent variable on various other factors, as opposed to the media agenda as the independent variable that is the key causal factor in shaping the public agenda. However, this same openness naturally leads the agenda setting theory to be less parsimonious, as its reinterpretations increasingly limit the theory’s simplicity. A high correlation in numerous studies between individual issue agenda and the agendas set by the media show that whichever way the theory is interpreted, agenda setting theory has a large theoretical scope, with many case examples found in a wide domain of public opinions and behaviors.

Since news and media sources are only able to provide a little amount of information about a variety of events and issues, people in the media must focus on key issues. Eventually, these issues on the public agenda naturally become more pronounced in the public consciousness. This theory provides a claim of figuratively knowing which came first: the chicken or the egg. In this case, if the media's agenda is the chicken and the public's opinions are eggs, then the chicken came first. Of course, not everyone is susceptible to the effects of agenda-setting, and factors such as trust, political involvement, and an innate need for orientation all contribute to a single person's psychological profile in regards to this theory.

Those who are interested in continuing an education in communication theories would do well to refer to the bibliography below, which contains numerous reference works and studies about this theory of agenda setting and the potential effects the media's agenda may have on the audience public consciousness. Educate yourself, and become more aware of how such theories of communication influence what elements are included in the ongoing public debate, as well as how personally susceptible you might be to some of the effects of this theory.