||This article is written like a personal reflection or opinion essay rather than an encyclopedic description of the subject. (June 2012)|
Agenda-setting theory describes the "ability [of the news media] to influence the salience of topics on the public agenda." That is, if a news item is covered frequently and prominently the audience will regard the issue as more important. Agenda-setting theory was formally developed by Dr. Max McCombs and Dr. Donald Shaw in a study on the 1968 presidential election. In the 1968 "Chapel Hill study," McCombs and Shaw demonstrated a strong correlation (r > .9) between what 100 residents of Chapel Hill, North Carolina thought was the most important election issue and what the local and national news media reported was the most important issue. By comparing the salience of issues in news content with the public's perceptions of the most important election issue, McCombs and Shaw were able to determine the degree to which the media determines public opinion. Since the 1968 study, published in a 1972 edition of Public Opinion Quarterly, more than 400 studies have been published on the agenda-setting function of the mass media, and the theory continues to be regarded as relevant.
The theory of agenda-setting can be traced to the first chapter of Walter Lippmann’s 1922 classic, Public Opinion. In that chapter, "The World Outside The Pictures In Our Heads," Lippmann pointed out that the media dominates over the creation of pictures in our head and memory; he believed that the public reacts not to the actual event produced but the picture of the actual event in our memory. Lippmann argues that the mass media are the principal connection between events in the world and the images in the minds of the public. Without using the term "agenda-setting," Walter Lippmann was writing about what we today would call "agenda-setting." Following Lippmann, in 1963, Bernard Cohen observed that the press "may not be successful much of the time in telling people what to think, but it is stunningly successful in telling its readers what to think about. The world will look different to different people," Cohen continues, "depending on the map that is drawn for them by writers, editors, and publishers of the paper they read."  As early as the 1960s, Cohen had expressed the idea that later led to formalization of agenda-setting theory by McCombs and Shaw.
Though Maxwell McCombs already had some interest in the field he was exposed to Cohen's work while serving as a faculty member at UCLA, and it was Cohen’s work that heavily influenced him, and later Donald Shaw. The concept of agenda setting was launched by McCombs and Shaw during the 1968 presidential election in Chapel Hill, North Carolina. They examined Lippmann’s idea of construction of the pictures in our heads by comparing the issues on the media agenda with key issues on the undecided voters’ agenda. They found evidence of agenda setting by identifying that salience of the news agenda is highly correlated to that of the voter’s agenda.
A relatively unknown scholar named G. Ray Funkhouser performed a study highly similar to McCombs and Shaw’s around exactly the same time the authors were formalizing the theory. All three scholars - McCombs, Shaw, and Funkhouser - even presented their findings at the same academic conference. Funkhouser’s article was published later than McCombs and Shaw’s, and Funkhouser doesn’t receive as much credit as McCombs and Shaw for discovering agenda setting. According to Everett Rogers, there are two main reasons for this. First, Funkhouser didn’t formally name the theory. Second, Funkhouser didn’t pursue his research much past the initial article. Rogers also suggests that Funkhouser was geographically isolated at Stanford, cut off from interested researchers, whereas McCombs had Shaw and got other people interested in agenda setting research.
Core Assumptions and Statements 
Agenda- Setting is the media’s ability to transfer salience issues through their news agenda so the public agenda can form their understanding of the salience issues. Two basic assumptions underlie most research on agenda-setting: (1) the press and the media do not reflect reality; they filter and shape it; (2) media concentration on a few issues and subjects leads the public to perceive those issues as more important than other issues. "Mass Communication plays an important role in our society its purpose is to inform the public about current and past events. Mass communication is defined in “ Mass Media, Mass Culture” as the process whereby professional communicators use technological devices to share messages over great distances to influence large audiences. Within this process the media, which can be a newspaper, a book and television, takes control of the information we see or hear. The media then uses gatekeeping and agenda setting to “control our access to news, information, and entertainment” (Wilson 14). Gatekeeping is a series of checkpoints that the news has to go through before it gets to the public. Through this process many people have to decide whether or not the news is to be seen or heard. Some gatekeepers might include reporters, writers, and editors. After gatekeeping comes agenda setting."(Wilson,2005) One of the most critical aspects in the concept of an agenda-setting role of mass communication is the time frame for this phenomenon. In addition, different media have different agenda-setting potential.
The Cognitive Effects of Agenda-Setting 
Agenda setting occurs through a cognitive process known as "accessibility."  Accessibility implies that the more frequently and prominently the news media cover an issue, the more instances of that issue become accessible in audience's memories. When respondents are asked what the most important problem facing the country is, they answer with the most accessible news issue in memory, which is typically the issue the news media focus on the most. The agenda-setting effect is not the result of receiving one or a few messages but is due to the aggregate impact of a very large number of messages, each of which has a different content but all of which deal with the same general issue. Mass-media coverage in general and agenda-setting in particular also has a powerful impact on what individuals think that other people are thinking, and hence they tend to allocate more importance to issues that have been extensively covered by mass media.
Agenda-setting vs. Agenda-building 
As more scholars published articles on agenda-setting theories it became evident that the process involves not only active role of media organizations, but also participation of the public  as well as policymakers. Rogers and Dearing described the difference between agenda-setting and agenda-building based on the dominant role of media or public. Thus “setting” an agenda refers to the effect of the media agenda on society, transfer of the media agenda to the public agenda, while “building” an agenda includes “some degree of reciprocity” between the mass media and society  where both media and public agendas influence public policy.
Berkowitz has implemented a more nuanced analysis of agenda-setting and agenda-building theories by introducing the terms policy agenda-setting and policy agenda-building. He argues that when scholars investigate only the linkage between media and policymakers, it is still appropriate to use the notion of policy agenda-setting. However, when the focus is placed not only on policymakers’ personal agendas, but also on the broader salient issues where media represent only one indicator of public sentiment, Berkowitz suggests talking about policy agenda-building.
Three Types of Agenda-Setting 
1) Public agenda setting- Is in which most important public issues or problems are measured by public opinion and agenda.Example (people's strong beliefs)
2) Media agenda setting- Is the pattern in which news coverage print and broadcast news gets measured through the importance and depth of the story. Example (Presidential race information)
3) Policy agenda setting- Is more scientific in its nature it’s the thought in which we pay more attention to how the media or public might influence elite policy makers. Example (President, Congress, Religion)
Mass communication research, Rogers and Dearing argue, has focused a great deal on public agenda setting - e.g., McCombs and Shaw, 1972 - and media agenda setting, but has largely ignored policy agenda setting, which is studied primarily by political scientists. As such, the authors suggest mass communication scholars pay more attention to how the media and public agendas might influence elite policy maker's agendas (i.e., scholars should ask where the President or members of the U.S. Congress get their news from and how this affects their policies). Writing in 2006, Walgrave and Van Aelst took up Rogers and Dearing's suggestions, creating a preliminary theory of political agenda setting, which examines factors that might influence elite policy makers' agendas.
The Audience-Contingent Effects of Agenda-Setting 
In an attempt to overcome mirror-image effects of agenda-setting that implied direct influence of media agenda on the audience, several scholars proposed that the model of agenda-setting should include individual/collective audience characteristics and/or real-world conditions that are likely to affect issue importance. They discovered that certain individual and group characteristics are likely to act as contingent conditions of media impact and proposed a model of “audience effects”.
According to the audience effects model media coverage interacts with the audience’s pre-existing sensitivities to produce changes in issue concerns. Thus media effects are contingent on issue-specific audience characteristics. For instance, for high-sensitivity audiences who are most affected by a certain issue or a problem, the salience of this issue increases substantially with news exposure, while the same exposure has little effect on other groups. But there is also the index of curiosity which the audience measures the extent or need for orientation then in turn motivates them to allow the media to shape their views within the extent of their orientation. Erbring, Goldenberg and Miller have also demonstrated that people who do not talk about political issues are more subject to agenda-setting influence because they depend more heavily on media content than those who receive information from other sources, including their colleagues and friends.
Another factor that causes variations in the correlation between the media and public agenda is whether an issue is "obtrusive" or "unobtrusive”  or in other terms have high or low issue threshold. Obtrusive or issues with low threshold are generally the ones that affect nearly everyone and with which we can have some kind of personal experience (e.g. city-wide crime or inflation at the gas pump). Because of their link to personal concerns, these issues almost compel attention from political elites as well as the news media. Moreover, with this type of issues the problem would be of general concern even without attention from the news media. Unobtrusive or high threshold issues are those issues that are generally remote from just about everyone (e.g. wrongdoing high up in the government like Watergate, plight of refugees from Syria). Research performed by Zucker suggests that an issue is obtrusive if most members of the public have had direct contact with it, and less obtrusive if audience members have not had direct experience. This means that the less direct experience people have with an issue, the greater is the news media’s influence on public opinion on that issue 
Moreover, unobtrusive or high threshold issues do not pertain into media agenda as quickly as obtrusive issues and therefore require a buildup, which is a function of more than the amount of space and/or time the media devote to the story. The latter may push the story past the threshold of inattention, but it is also important to look at the kind of coverage to explain how a certain incident becomes an issue.
Role of Policymakers in Agenda-Setting Process 
Some groups have a greater ease of access than others and are thus more likely to get their demands placed on agenda than others. For instance, policymakers have been found to be more influential than the overall group of news sources because they often better understand journalists’ needs for reliable and predictable information and their definition of newsworthiness. Cobb and Elder ascribed even more importance to decision makers, claiming that in order for an issue to attain agenda status, it must be supported by at least some of key decision makers as they act as guardians of the formal agenda. They also asserted that certain personages in the media can act as opinion leaders and bring media coverage to a particular issue. Government-affiliated news sources have higher success rates in becoming media agenda and have been found by a number of scholars to be the most frequently appearing of sources at the local, state, and national levels.
News sources can also provide definitions of issues, thus determining the terms of future discussion and framing problems in particular ways. What interpretation of “reality” will dominate public discourse has implications for the future of the social problem, for the interest groups and policymakers involved, and for the policy itself. For example, Gusfield argues that the highway deaths associated with alcohol consumption can be interpreted as a problem of irresponsible drunken drivers, insufficient automobile crash-worthiness, a transportation system overly dependent on cars, poor highway design, excessive emphasis on drinking in adult social life. Different ways of framing the situation may compete to be accepted as an authoritative version of reality, consequently spurring competition between sources of information for definition of an issue. Very powerful resources of information can even influence whether an issue receives media attention at all.
The relationship of media and policymakers is symbiotic and is controlled by shared culture of unofficial set of ground rules as journalists need access to official information and policymakers need media coverage; nevertheless the needs of journalists and policymakers are often incompatible because of their different orientation in time as powerful sources are at their best in routine situations and react more slowly when crisis or disaster occur. Consequently, policymakers who understand the rules of this culture the best will be most capable of setting their agendas and issue definitions. On the other hand, media also influence policymakers when government officials and politicians take the amount of media attention given to an issue as an indirect expression of public interest in the issue.
Need for Orientation 
Agenda-setting studies typically show variability in the correlation between media and public agenda. To explain differences in the correlation, McCombs and colleagues created the concept of "need for orientation," which "describes individual differences in the desire for orienting cues and background information."
Two concepts: relevance and uncertainty, define an individual's need for orientation. Relevance suggests that an individual will not seek news media information if an issue is not personally relevant. Hence, if relevance is low, people will feel the need for less orientation. There are many issues in our country that are just not relevant to people, because they do not affect us. Many news organizations attempt to frame issues in a way that attempts to make them relevant to its audiences. This is their way of keeping their viewership/readership high. "Level of uncertainty is the second defining condition of need for orientation. Frequently, individuals already have all the information that they desire about a topic. Their degree of uncertainty is low." When issues are of high personal relevance and uncertainty low, the need to monitor any changes in those issues will be present and there will be a moderate the need for orientation. If at any point in time viewers/readers have high relevance and high uncertainty about any type of issue/event/election campaign there was a high need for orientation.
David Weaver(1977) adapted the concept of ‘individual’s need for orientation’ defined regarding relevance and uncertainty. Research done by Weaver in 1977 suggested that individuals vary on their need for orientation. Need for orientation is a combination of the individual’s interest in the topic and uncertainty about the issue. The higher levels of interest and uncertainty produce higher levels of need for orientation. So the individual would be considerably likely to be influenced by the media stories (psychological aspect of theory). Schonbach and Weaver(1985) ’s study with a focus on need for orientation showed the strongest agenda setting effects at a moderate need for orientation(under conditions of low interest and high uncertainty).
Role of Public in Agenda-Building process 
The agenda-building perspective ascribes importance not only to mass media and policymakers, but also to social process, to mutually interdependent relation between the concerns generated in social environment and the vitality of governmental process. Thus according to Cobb and Elder, the agenda-building framework makes allowances for continuing mass involvement and broaden the range of recognized influences on the public policy-making process.
This idea of mass involvement has become more prominent with the advent of the Internet and its potential to make everyone a pamphleteer. Increase in the role of citizens in agenda setting sheds light on a new direction in the traditional agenda-building research.
Kim and Lee  noted that the agenda-setting research on the Internet differs from traditional agenda-setting research with respect that the Internet is in competition with traditional media and has enormous capacity for contents' and users’ interactivity. Lee, Lancendorfer and Lee  argued that "various opinions about public issues are posted on the Internet bulletin boards or the Usenet newsgroup by Netizens, and the opinions then form an agenda in which other Netizens can perceive the salient issue". Scholars also stated that the Internet plays role in forming Internet user’s opinion as well as the public space.
Kim and Lee  studied the pattern of the Internet mediated agenda-setting by conducting a case study of 10 cases that have a great ripple effect in Korea for 5 years (from 2000 until 2005). Scholars found that a person’s opinion could be disseminated through various online channels and could synthesize public opinion that influences news coverage. Their study suggests ‘reversed agenda effects’, meaning that public agenda could set media agenda. Maxwell McCombs  also mentioned "reverse agenda-setting" in his recent textbook as a situation where public concern sets the media agenda.
According to Kim and Lee, agenda-building through the Internet take the following three steps: 1) Internet-mediated agenda-rippling: an anonymous netizen’s opinion spreads to the important agenda in the Internet through online main rippling channels such as blogs, personal homepages, and the Internet bulletin boards. 2) agenda diffusion in the Internet: online news or web-sites report the important agenda in the Internet that in turn leads to spreading the agenda to more online publics. 3) Internet-mediated reversed agenda-setting: traditional media report online agenda to the public so that the agenda spread to both offline and online publics. However, scholars concluded that the Internet-mediated agenda-setting or agenda-building processes not always occur in consecutive order. For example, the agenda that was reported by traditional media can come to the fore again through the online discussion or the three steps can occur simultaneously in a short period of time.
Several real-world examples provide evidence that the Internet-community, particularly bloggers, can push their own agenda into public agenda, then media agenda, and, eventually, into policy agenda. For instance, in 2005 Eason Jordan, the chief news executive at CNN, abruptly resigned after being besieged by the online community after saying, according to various witnesses, that he believed the United States military had aimed at journalists in Iraq and killed 12 of them. Similarly, in 2002 Senate majority leader Trent Lott had to resign due to his inappropriate racist remarks that were widely discussed in the blogosphere. However bloggers attract attention not only to oust journalists and politicians. An online investigation on technical problems with electronic voting machines started by an activist Bev Harris in 2003 eventually forced traditional media outlets to address issue of electronic voting malperformance. This in turn made Diebold, a company that produces these machines, to acknowledge its fault and take measures to fix it.
Framing or Second-Level Agenda-Setting? 
As agenda setting theory has been developed, scholars pointed out attributes that describe the object. Each of the objects on an agenda has a lot of attributes containing cognitive component such as information that describes characteristics of the object, and an affective component including tones(positive, negative, neutral) of the characteristics on agenda.“Framing is a quality of communication that leads others to accept one meaning over another. It is a skill with profound effects on how organizational members understand and respond to the world in which they live. It is a skill that most successful leaders possess, yet one that is not often taught. According to Fairhurst & Sarr (1996) framing consists of three elements: language, thought and forethought.”
McCombs et al. (1998) demonstrated that agenda-setting research at the second level deals with the influence of ‘attribute’ salience, whereas the first level agenda-setting illustrates the influence of ‘issue’ salience. Balmas and Sheafer (2010) argued that the focus at the first level agenda-setting which emphasizes media’s role in telling us "what to think about" is shifted to media’s function of telling us "how to think about" at the second level agenda-setting. The second level of agenda-setting considers how the agenda of attributes affects public opinion (McCombs & Evatt, 1995). Furthermore, Ghanem(1997) demonstrated that the certain attributes agendas in the news with low psychological distance, drove compelling arguments for the salience of public agenda. The second level agenda setting differs from traditional agenda setting in that it focus on attribute salience, and public’s attribute agenda is regarded as one of the important variables.
There is a debate over whether framing theory should be subsumed within agenda-setting as "second-level agenda-setting." McCombs, Shaw, Weaver and colleagues generally argue that framing is a part of agenda-setting that operates as a "second-level" or secondary effect. Dietram Schefuele has argued the opposite. Scheufele argues that framing and agenda-setting possess distinct theoretical boundaries, operate via distinct cognitive processes (accessibility vs. attribution), and relate to different outcomes (perceptions of issue importance vs. interpretation of news issue). According to Weaver, framing and second-level agenda setting have the following characteristics:
- Both are more concerned with how issues or other objects are depicted in the media than with which issues or objects are more or less prominently reported.
- Both focus on most salient or prominent aspects of themes or descriptions of the objects of interest.
- Both are concerned with ways of thinking rather than objects of thinking
- Framing does seem to include a broader range of cognitive processes – moral evaluations, causal reasoning, appeals to principle, and recommendations for treatment of problems – than does second-level agenda setting (the salience of attributes of an object)
Based on these shared characteristics, McCombs and colleagues recently argued that framing effects should be seen as the extension of agenda setting. In other words, according to them, the premise that framing is about selecting "a restricted number of thematically related attributes"  for media representation can be understood as the process of transferring the salience of issue attributes (i.e., second-level agenda setting). That is, according to McCombs and colleagues’ arguments, framing falls under the umbrella of agenda setting.
According to Price and Tewksbury, however, agenda setting and framing are built on different theoretical premises: agenda setting is based on accessibility, while framing is concerned with applicability (i.e., the relevance between message features and one’s stored ideas or knowledge). Accessibility-based explanation of agenda setting is also applied to second-level agenda setting. That is, transferring the salience of issue attributes (i.e., second-level agenda setting) is a function of accessibility.
For framing effects, empirical evidence shows that the impact of frames on public perceptions is mainly determined by perceived importance of specific frames rather than by the quickness of retrieving frames. That is, the way framing effects transpires is different from the way second-level agenda setting is supposed to take place (i.e., accessibility). On a related note, Scheufele and Tewksbury  argues that, because accessibility and applicability vary in their functions of media effects, "the distinction between accessibility and applicability effects has obvious benefits for understanding and predicting the effects of dynamic information environments."
Taken together, it can be concluded that the integration of framing into agenda setting is either impossible because they are based on different theoretical premises or imprudent because merging the two concepts would result in the loss of our capabilities to explain various media effects.
Agenda setting vs. Framing 
Scheufele and Tewksbury argue that "framing differs significantly from these accessibility-based models [i.e., agenda setting and priming]. It is based on the assumption that how an issue is characterized in news reports can have an influence on how it is understood by audiences;" the difference between whether we think about an issue and how we think about it. “To use language, people must think and reflected on their own interpretive frameworks and those of others. Leaders must learn to frame spontaneously in certain circumstances. Being able to do so had to do with having the understanding and forefront to predict framing opportunities. In other words, one must plan in order to be spontaneous.” (Deetz, Tracy & Simpson, 2000). Framing and agenda setting differs in their functions in the process of news production, information processing and media effects.
(a) News production: Although "both frame building and agenda building refer to macroscopic mechanisms that deal with message construction rather than media effects," frame building is more concerned with the news production process than agenda building. In other words, "how forces and groups in society try to shape public discourse about an issue by establishing predominant labels is of far greater interest from a framing perspective than from a traditional agenda-setting one."
(b) News processing: For framing and agenda setting, different conditions seem to be needed in processing messages to produce respective effects. Framing effect is more concerned with audience attention to news messages, while agenda setting is more with repeated exposure to messages.
(c) Locus of effect: Agenda-setting effects are determined by the ease with which people can retrieve from their memory issues recently covered by mass media, while framing is the extent to which media messages fit ideas or knowledge people have in their knowledge store.
Accessibility (Agenda setting) vs. Applicability (Framing)
(a) Accessibility (Agenda setting) Increasing attention has been devoted to examining how agenda setting occur in terms of their psychological mechanisms (Holbrook & Hill, 2005). Price and Tewksbury (1997) argued that agenda setting effects are based on the accessibility model of information processing. Accessibility can be defined as “how much” or “how recently” a person has been exposed to certain issues (Kim et al., 2002). Specifically, individuals try to make less cognitive effort in forming social judgments, they are more likely to rely on the information that is easily accessible (Higgins, 1996). This leads to a greater probability that more accessible information will be used when people make judgments on certain issues (Iyeanger & Kinder, 1987; Scheufele & Tewksbury, 2007).
The concept of accessibility is the foundation of a memory-based model (Scheufele, 2000). It assumes that individuals make judgments on the issues based on information that is easily available and retrievable from their memory (Tulving & Watkins, 1975; Hastie & Park, 1986; Iyengar, 1990). Tversky and Kahneman (1974) also argue that the formation of individuals’ judgments directly correlates with “the ease in which instances or associations could be brought to mind” (p. 208). When individuals receive and process information, they develop memory traces that can be easily recalled to make decisions on a certain issue. Agenda setting, in this regard, can make certain issue to be easily accessed in individual’s memory when forming judgment about the issue.
According to Chaffee & Berger’s 1997 criteria for scientific theories "The Agenda-Setting Theory comes from a scientific perspective, because it predicts that if people are exposed to the same media, they will place importance on the same issues. Agenda-Setting is a good theory."
1- It has explanatory power because it explains why most people prioritize the same issues as important. 2- It has predictive power because it predicts that if people are exposed to the same media, they will feel the same issues are important. 3- It is parsimonious because it isn’t complex, and it is easy to understand. 4- It can be proven false. If people aren’t exposed to the same media, they won’t feel the same issues are important. 5- It’s meta-theoretical assumptions are balanced on the scientific side 6- It is a springboard for further research 7- It has organizing power because it helps organize existing knowledge of media effects.
(b) Applicability (Framing)
Framing focuses on the applicability of individual’s pre-existing cognitive schema, which is different from agenda setting and priming (Schefuele, 2000; Kim et al., 2002). Framing is the process of selecting certain aspects of an issue to bring people’s attention and to lead them a particular line of interpretation (Entman, 1993; Scheufele, 1999). Also, the media’s selective uses of certain frames can affect the way the audience thinks about the issue (Oh, & Kim, 2010). This may sound similar to attribute agenda setting. Both seem to examine which attributes or aspects of an issue are emphasized in the media (Kim et al., 2011). Some scholars even argue that framing should be considered as an extension of agenda setting (McCombs, 1997).
However, framing is based on the applicability model, which is conceptually different from the accessibility model used in agenda setting. According to Goffman (1974), individuals actively classify and interpret their life experiences to make sense of the world around them. These classifications and interpretations then become the individual’s pre-existing and long-standing schema. Framing influences how audience thinks about issues, not by making certain aspects more salient than others, but by invoking interpretive cues that correspond to the individuals’ pre-existing schema (Scheufele, 2000). Also, framing is when these interpretive cues correspond with or activate individuals’ pre-existing cognitive schema (Kim et al., 2002). Applicability, in this regard, refers to finding the connection between the message in the media and the framework individuals employ to interpret the issue (Scheufele & Tewksbury, 2007).
Kim and his colleagues (2002) provide distinction between the applicability and accessibility models is important in terms of issue salience. Framing assumes that each individual will have its own interpretation of an issue, regardless of the salience of an issue. Specifically, it focuses on the “terminological or semantic differences” of how an issue is described. Agenda setting, on the other hand, assume that only salient issues in the media will become accessible in people’s minds when they evaluate or make judgments on the issue. Taken together, the accessibility of issue salience makes the two models of information processing different (Scheufele, 2000).
Non-Political Application 
McCombs and Shaw originally established agenda-setting within the context of a presidential election. Many subsequent studies have looked at agenda setting in the context of an election or in otherwise political contexts. However, more recently scholars have been studying agenda setting in the context of brand community. A brand is defined as what resides in the minds of individuals about a product or service. Brand community is described as a "specialized, non-geographically bound community based on a structured set of social relations among admirers of a brand." Under these definitions more than just material products can qualify as a brand, political candidates or even celebrities could be viewed as a brand as well. The theory can also be applied to commercial advertising, business news and corporate reputation, business influence on federal policy, legal systems, trials, roles of social groups, audience control, public opinion, and public relations.
Since the Chapel Hill study, a great deal of research has been carried out to discover the agenda setting influence of the news media. The theory has not been limited to elections, and many scholars constantly explored the agenda setting effect in a variety of communication situations. This explains that agenda setting has a theoretical value which is able to synthesize social phenomenon and to build new research questions.
Another contribution of agenda setting is to show the power of media. Since the study of 1940 US presidential election in Erie County, Ohio by Paul Lazarsfeld and his colleagues, little evidence of mass communication effects has been found over the next twenty years. In 1960, Joseph Klapper’s The Effects of Mass Communication also declared the limited effect of media. Agenda setting caused a paradigm shift in the study of media effects from persuasion to informing by connecting media content and its effects on the public.
Future of Agenda-Setting Theory 
As a result in the changes in technology, there have been major changes in the ways in which people receive their news. Newspapers, broadcast television, and terrestrial radio are all examples of "vertical media" which is rapidly declining. Now the more common form of media is "horizontal media." The main differences are that it is more specialized and people pay premiums for this type of media. Horizontal media includes cable television and satellite radio as well as other media that is paid for. Horizontal and vertical media intersect in virtual brand communities, or the Internet. This is because the Internet is free like vertical media but serves specialized interest groups like horizontal media. Now people seek news in different ways, the media and its agenda have had to adapt. Although the major tenets of agenda setting theory have maintained their importance with the changes of new media, an aspect of agenda setting theory has changed. This change is known as Agenda Melding which focuses "on the personal agendas of individuals vis-à-vis their community and group affiliations  ". This means that individuals join groups and blend their agendas with the agendas of the group. Then groups and communities represent a "collected agenda of issues" and "one joins a group by adopting an agenda." On the other hand, agenda setting defines groups as "collections of people based on some shared values, attitudes, or opinions" that individuals join. This is different from traditional agenda setting because according to Shaw et al. individuals join groups in order to avoid social dissonance and isolation that is also known as "need for orientation ". Therefore in the past in order to belong people would learn and adopt the agenda of the group. Now with the ease of access to media, people form their own agendas and then find groups that have similar agendas that they agree with. The advances in technology have made agenda melding easy for people to develop because there is a wide range of groups and individual agendas. The Internet makes it possible for people all around the globe to find others with similar agendas and collaborate with them. In the past agenda setting was limited to general topics and it was geographically bound because travel was limited.
1) Agenda setting is an inherently causal theory, but few studies establish the hypothesized temporal order (the media should set the public's agenda).
2) The measurement of the dependent variable was originally conceptualized as the public's perceived issue "salience," but subsequent studies have conceptualized the dependent variable as awareness, attention, or concern, leading to differing outcomes.
3) Studies tend to aggregate media content categories and public responses into very broad categories, resulting in inflated correlation coefficients.
See also 
- Availability heuristic
- Mass hysteria
- Policy by press release
- Political agenda
- Politico-media complex
- Iyengar, S; Kinder, D. News that mattes: University of Chicago Press. Chicago, IL.
- Iyengar, S (1990). "The accessibility bias in politics: Television news and public opinion". International Journal of Public Opinion Research 2: 1–15.
- Dearing, J; Rogers, E (1988). "Agenda-setting research: Where has it been, where is it going?". Communication Yearbook 11: 555–594.
- Noelle-Neumann, E (1977). "Turbulances in the climate of opinion:Methodological applications of the spiral of silence theory". Public Opinion Quarterly. 4 (2): 143–158.
- Erbring, L; Goldenberg, E.N.&Miller,A.H. (1980). "Front-page news and real-world cues: A new look at agenda-setting by the media.". American Journal of Political Science 24: 16–49.
- Lang, G.E.; Lang, K. (1981). "Watergate: An exploration of the agenda-building process". In Wilhout, G.C. Mass Communication Review Yearbook (Beverly Hills, CA: Sage) 2: 447–468. Unknown parameter
- Berkowitz, D (1992). "Who sets the media agenda? The ability of policymakers to determine news decisions.". In Kennamer, J.D. Public opinion, the press, and public policy (Westport,CT:Praeger) 2: 81–102.
- Rogers, E; Dearing, J (1988). "Agenda-setting research: Where has it been, where is it going?". Communication Yearbook 11: 555–594.
- Walgrave, S; Van Aelst, P (2006). "The contingency of the mass media's political agenda setting power: Toward a preliminary theory". Journal of Communication 56: 88–109.
- Cobb, R.W.; Elder,C. (1971). "The politics of agenda-building: An alternative perspective for modern democratic theory". Journal of Politics 33: 892–915.
- Hilgarten, S; Bosk, C.L. (1988). "The rise and fall of social problems: A public arenas model". American Journal of Sociology 94: 53–78.
- Gusfield, J.R. (1981). The culture of public problems. Chicago, IL: University of Chicago Press.
- Gans, H.J. (1979). Deciding what’s news. New York: Panteon.
- Mccombs, (2004) p. 55
- al.], Donald L. Shaw, Maxwell E. McCombs ; in association with Lee B. Becker ... [et (1977). The emergence of American political issues : the agenda-setting function of the press (1. repr. ed.). St. Paul: West Pub. Co. ISBN 0-8299-0142-6.
- Weaver, D (1977). "Political issues and voter need for orientation". In D.L. Shaw and M.E. McCombs (Eds.), The emergence of American public issues: 107–120.
- Perloff, edited by Sidney Kraus, Richard M. (1985). Mass media and political thought : an information-processing approach (1. print. ed.). Beverly Hills: Sage Publications. ISBN 0-8039-2516-6.
- Benkler, Y (2006). The wealth of networks: How Social production transforms markets and freedom. New Heaven,CT: Yale University Press.
- Kim, S. T.; Lee (2006). "New functions of Internet mediated agenda-setting: Agenda-rippling and reversed agenda-setting". Korean Journal of Journalism & Communication Studies 50 (3): 175–205.
- Lee, B; Karen and Lee (Mar 2005). "Agenda-setting and the internet: The intermedia influence of internet bulletin boards on newspaper coverage of the 2000 general election in South Korea". Asian Journal of Communication 15 (1): 57–71.
- McCombs, Maxwell (2004). Setting the Agenda: The Mass Media and Public Opinion (Repr. ed.). Cambridge: Blackwell Pub. p. 198. ISBN 978-0-7456-2313-9.
- Seelye, K.Q. "Resignation at CNN shows the growing influence of blogs". Retrieved 14 February.
- McCombs, M. E., Shaw, D. L., & Weaver, D. H. (1997). Communication and democracy: Explorining the intellectual frontiers in agenda-setting theory. Mahwah, NJ: Erlbaum.
- McCombs, M. E., Shaw, D. L., & Weaver, D. H. (1997). p. 106
- Price, V., & Tewksbury, D. (1997). News values and public opinion: A theoretical account of media priming and framing. In G. Barnett & F. Boster (Eds.), Progress in communication sciences (pp. 173-212). Norwood, N.J.: Ablex Pub. Corp.
- Nelson, T., Clawson, R., & Oxley, Z. (1997). Media framing of a civil liberties conflict and its effect on tolerance. American Political Science Review, 91(3), 567-583.
- Scheufele, D. A., & Tewksbury, D. (2007). Framing, agenda setting, and priming: The evolution of three media effects models. Journal of Communication, 57(1), 9-20.
- Ragas, Matthew; Marilyn Roberts (2009). "Agenda Setting and Agenda Melding in an Age of Horizontal and Vertical Media: A New Theoretical Lens for Virtual Brand Communities". Journalism & Mass Communication Quarterly 86 (1): 45–64. ISSN 1077-6990.
- Carroll, CE and McCombs, ME (2003). "Agenda-Setting Effects of Business News on the Public’s Images and Opinions about Major Corporations.". Corporate Reputation Review 6 (1). Text "pages36-46" ignored (help)
- Berger B. (2001). Private Issues and Public Policy: Locating the Corporate Agenda in Agenda-Setting Theory. Journal of Public Relations Research, 13(2), 91–126
- Ramsey & McGuire, 2000
32. Overview of agenda setting research in Journal of Communication (1993). Symposium: agenda setting revisited. 43(2), 58-127. 33. Wilson,James R., and Roy S.Wilson. Mass Media, Mass Culture, Fifth Edition.Boston.Mc Graw Hill, 2001. 34. Cragan, J.F., & Shields, D. C. (1998). Understanding communication theory: The communicative forces of human action. Needham Heights, MA: Allyn & Bacon, 10, 264,-265, 281, 313. 35. Kosicki, G. (1993). Problems and opportunities in agenda-setting research. Journal of Communication, 43(2), 100-127.
Further reading 
||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (April 2009)|
- Balmas M. and Sheafer T. Candidate image in election campaigns: attribute agenda setting, affective priming, and voting intentions. International Journal of Public Opinion Research Vol. 22 No. 2.
- Cohen, B. (1963). The Press and Foreign Policy. Princeton, NJ: Princeton University Press. ISBN 978-0-87772-346-2
- Davie W. R. and Maher T. M. (2006) Maxwell McCombs: Agenda-Setting Explorer. Journal of Broadcasting & Electronic Media 50(2), 358–364.
- Druckman, J., Jacobs, L., Ostermeir. (2004). Candidate Strategies to Prime Issues and Image. Journal of Politics Vol. 66 No.4, 1180-1202.
- Groshek J. (2008). Homogenous Agendas, Disparate Frames: CNN and CNN International Coverage online. Journal of broadcasting and electronic media. 52(1), 52-68.
- Hayes, D. (2008). "Does the Messenger Matter? Candidate-Media Agenda Convergence and Its Effects on Voter Issue Salience". Political Research Quarterly 61 (1): 134–146. doi:10.1177/1065912907306472. ISSN 1065-9129.
- Huckins, K (1999). Interest-group influence on the media agenda: A case study. Journalism & Mass Communication Quarterly, 76, 76-86.
- Iyengar, S., Kinder, D.R. (1986) More Than Meets the Eye: TV News, Priming, and Public Evaluations of the President. Public Communication and Behavior, Vol.1 New York: Academic.
- Kosicki, G. M. (1993). Problems and Opportunities in Agenda-Setting Research. Journal of Communication. Vol. 43, No. 2, 100–127.
- Kosicki, G. (2002). The media priming effect: news media and considerations affecting political judgements. In D. Pfau (Ed.), The persuasion handbook: Developments in theory and practice (p. 63-80). Thousand Oaks: Sage Publications.ISBN 0-7619-2006-4
- Kim, S., Scheufele, D.A., & Shanahan, J. (2002). Think about it this way: Attribute agenda-setting function of the press and the public’s evaluation of a local issue.
Journalism & Mass Communication Quarterly, 79, 7-25.
- Kiousis, S., & McCombs, M. (2004). Agenda-setting effects and attitude strength: Political figures during the 1996 Presidential elections. Communication Research, 31, 36-57.
- Lippmann, W. (1922). Public Opinion. New York: Macmillan.
- McCombs, Maxwell E.; Donald L. Shaw (1972). "The Agenda-Setting Function of Mass Media". Public Opinion Quarterly 36 (2): 176. doi:10.1086/267990. ISSN 0033-362X.
- McCombs, M.E., and D.L. Shaw. (1993). The Evolution of Agenda-Setting Research: Twenty-Five Years in the Marketplace of Ideas. Journal of Communication. Vol. 43, No. 2, p. 58 – 67
- Reiley, K. (2008, Nov.20). The Never-ending campaign. Interview. p 56.
- Revkin, A., Carter, S., Ellis,J., and McClean A. (2008, Nov.) On the Issues: Climate Change. The New York Times.
- Severin W., & Tankard, J. (2001). Communication Theories: Origins, Methods and Uses in Mass Communication (5th ed.). New York: Longman.ISBN 978-0-8013-3335-4
- Tanjong,, Enoh; Gaddy, Gary D. (1994). "The Agenda-Setting Function of the International Mass Media: The Case of Newsweek in Nigeria". Africa Media Review 8 (2): 1–14.
- Wanta, W., & Wu, Y.C. (1995). Interpersonal communication and the agenda-setting process. Journalism Quarterly, 69, 847-855.
- Weaver, D.H. (2007, Feb.) Thoughts on Agenda Setting, Framing, and Priming. Journal of Communication. Vol. 57 No. 1, 142 - 147.
- Yagade, A., & Dozier, D.M. (1990). The media agenda-setting effect of concrete versus abstract issues. Journalism Quarterly, 67, 3-10.
- Overview of agenda setting research in Journal of Communication (1993). Symposium: agenda setting revisited. 43(2), 58-127.
- Wilson,James R., and Roy S.Wilson. Mass Media, Mass Culture, Fifth Edition.Boston.Mc Graw Hill, 2001.
- Cragan, J.F., & Shields, D. C. (1998). Understanding communication theory: The communicative forces of human action. Needham Heights, MA: Allyn & Bacon, 10, 264,-265, 281, 313.
- Kosicki, G. (1993). Problems and opportunities in agenda-setting research. Journal of Communication, 43(2), 100-127.