The propaganda model is a conceptual model in political economy advanced by Edward S. Herman and Noam Chomsky to explain how propaganda and systemic biases function in mass media. The model seeks to explain how populations are manipulated and how consent for economic, the theory posits that the way in which news is structured creates an inherent conflict of interest which acts as propaganda for undemocratic forces. Describing the medias societal purpose, Chomsky writes, the study of institutions and how they function must be scrupulously ignored, apart from fringe elements or a relatively obscure scholarly literature. The theory postulates five general classes of filters that determine the type of news that is presented in news media and these five classes are, Ownership of the medium, Mediums funding sources, Sourcing, Flak, Anti-communism and fear ideology. The first three are regarded by the authors as being the most important. The size and profit-seeking imperative of dominant media corporations create a bias, nevertheless, there remained a degree of diversity. The authors posit that these earlier radical papers were not constrained by corporate ownership and were free to criticize the capitalist system. Such conglomerates frequently extend beyond traditional media fields and thus have extensive financial interests that may be endangered when certain information is publicized, according to this reasoning, news items that most endanger the corporate financial interests of those who own the media will face the greatest bias and censorship. The second filter of the model is funding generated through advertising. Most newspapers have to attract advertising in order to cover the costs of production, without it, there is fierce competition throughout the media to attract advertisers, a newspaper which gets less advertising than its competitors is at a serious disadvantage. Lack of success in raising advertising revenue was another factor in the demise of the newspapers of the nineteenth and twentieth centuries. The theory argues that the buying the newspaper are the product which is sold to the businesses that buy advertising space. Even large media corporations such as the BBC cannot afford to place reporters everywhere and they concentrate their resources where news stories are likely to happen, the White House, the Pentagon,10 Downing Street and other central news terminals. Business corporations and trade organizations are also trusted sources of stories considered newsworthy, thus, the media has become reluctant to run articles that will harm corporate interests that provide them with the resources that they depend upon. This relationship also gives rise to a division of labor, in which officials have and give the facts. Journalists are then supposed to adopt an attitude that makes it possible for them to accept corporate values without experiencing cognitive dissonance. The fourth filter is flak, described by Herman and Chomsky as negative responses to a statement or program. It may take the form of letters, telegrams, phone calls, petitions, lawsuits, speeches and Bills before Congress and other modes of complaint, threat, business organizations regularly come together to form flak machines
A study found that in the lead up to the Iraq War, most sources were overwhelmingly in favor of the invasion.