Gatekeeping is the process through which information is filtered for dissemination, whether for publication, broadcasting, the Internet, or some other mode of communication. The academic theory of gatekeeping is found in multiple fields of study, including communication studies, journalism, political science, and sociology. It was originally focused on the mass media with its few-to-many dynamic but now gatekeeping theory also addresses face-to-face communication and the many-to-many dynamic inherent in the Internet. The theory was first instituted by social psychologist Kurt Lewin in 1943. Gatekeeping occurs at all levels of the media structure — from a reporter deciding which sources are chosen to include in a story to editors deciding which stories are printed or covered, and includes media outlet owners and even advertisers. Individuals can also act as gatekeepers, deciding what information to include in an email or in a blog, for example.
Gatekeeping is a process by which information is filtered to the public by the media. According to Pamela Shoemaker and Tim Vos, gatekeeping is the "process of culling and crafting countless bits of information into the limited number of messages that reach people every day, and it is the center of the media's role in modern public life. […] This process determines not only which information is selected, but also what the content and nature of the messages, such as news, will be." 
- In exercising its "surveillance" function, every news medium has a very large number of stories brought to its attention daily by reporters, wire services, and a variety of other sources.
- Due to a number of practical considerations, only a limited amount of time or space is available in any medium for its daily presentations of the news to its audience. The remaining space must be devoted to advertising and other content.
- Within any news organization there exists a news perspective, a subculture that includes a complex set of criteria for judging a particular news story - criteria based on economic needs of the medium, organizational policy, definitions of newsworthiness, conceptions of the nature of relevant audience, and beliefs about fourth estate obligations of journalists.
- This news perspective and its complex criteria are used by editors, news directors, and other personnel who select a limited number of news stories for presentation to the public. They then encode them in ways such that the requirements of the medium and the tastes of the audience are met.
- Therefore, personnel in the news organization become gatekeepers, letting some stories pass through the system but keeping others out.This then limits, controls, and shapes the public's knowledge of the totality of actual event occurring in reality."
Gatekeeping as a news process was identified in the literature as early as 1922, though not yet given a formal theoretical name. In his book, The Immigrant Press, Park explains the process, “out of all of the events that happen and are recorded every day by correspondents, reporters, and the news agencies, the editor chooses certain items for publication which he regards as more important or more interesting than others. The remainder he condemns to oblivion and the wastebasket. There is an enormous amount of news ‘killed’ every day” (p. 328).
Formally, gatekeeping was identified in Lewin’s (1943) publication Forces Behind Food Habits and Methods of Change. Working during World War II, Kurt Lewin conducted field research initially among Midwestern housewives to determine how to effectively change their families’ food consumption during this time of war. Lewin recognized that for food to go from a store or a garden to the dining table, there were various decision-making processes it had to pass on the way there. At a time when men were thought to control all household decisions, Lewin found that “food does not move by its own impetus. Entering or not entering a channel and moving from one section of a channel to another is affected by a ‘gatekeeper’” (p. 37). The gatekeeper,in this case, was typically the housewife, or sometimes a maid in more affluent households. Lewin’s research demonstrated that not all members of a family have equal weight in making household food decisions and that the wife, who typically shops for and prepares the food controls the gates, based on a variety of considerations. Lewin’s study published in 1943 became the impetus for another article in 1947 in which he introduces the idea of feedback in group decision making, which complicates the role of the gatekeeper. Feedback acknowledges that the set of considerations a gatekeeper uses in making decisions may vary depending on considerations of the group.
In 1950, Dr. David Manning White, a journalism professor at Boston University, looked at the factors an editor takes into consideration when deciding which news will make the paper and which news will not; intending to examine how a "gate keeper" examines his "gate" within a channel of mass communication. White contacted an editor, a man in his mid-40s with 25 years of experience, whom he calls "Mr. Gates." Mr. Gates was the wire editor of a morning newspaper in a mid-west city of 100,000 that had a circulation of 30,000. During the case study, Mr. Gates retained all copy that he rejected from the paper for a week. At the end of his shift, he made notes on why that story was rejected, assuming he could still remember the reason. At the end of the week that the study took place, White found that nine-tenths of the wire copy got rejected and the process is made by highly subjective decisions based on the editor’s own set of experiences, attitudes and expectations. White found that in this particular study, the majority of the rejections could be classified in two ways: 1) not worthy of being reported or 2) there was another story on the same event. Pertaining to the first reason, many of the explanations Mr. Gates gives are for rejection are “highly-subjective value judgments." Examples of this are seen when Mr. Gates writes "too Red" or "don't care for suicides" (386). Pertaining to the second reason of rejection, given for the majority of the rejections, Mr. Gates made no “personal” rejections to the copy, but there was simply no space available for it in the paper. The later the story came to Mr. Gates, the less of a chance it had to take up any valuable space remaining. White examined Mr. Gates’ performance for a specific day and put the data in tables which show the amount and type of news which appeared on the front pages and the total number of dispatches used. Mr. Gates admitted to preferring political news to other types of news and explained that he tries to avoid sensationalism and consistently leans more towards being “conservative” both in political views and in writing style. Observed patterns throughout the week also show that Mr. Gates leans away from stories filled with figures and statistics and prefers stories that contain more of a narrative. His notes and reasons for rejection can also show Mr. Gates’ writing standard, using “too vague,” “not interesting," and “dull writing” on a number of occasions. A question that White poses and says should be considered in this case study is, “Does the category really enter into the choice?” He concludes that as Mr. Gates is representing “gate keepers” and wire editors as a whole, there doesn't seem to be a particular choice of news by categories. During the week the case study took place, however, there was a strong emphasis on Human Interest stories because there was a large appeal to a story regarding a Cardinal of the Catholic Church. Mr. Gates also concludes that the gate keeper’s standards and taste should refer back to the audience and that they are the ones being served and pleased. His concluding remarks provide a great summary of the purpose and findings of the study. “Through studying his overt reasons for rejecting news stories from the press associations we see how highly subjective, how based on the “gate keeper’s” own set of experiences, attitudes and expectations the communication of “news” really is” (390).
The Gatekeeping Model
Lewin identified several parts of the gatekeeping process in his 1943 article: 
1) Information moves step by step through channels. The number of channels varies and the amount of time in each channel can vary.
2) Information must pass a “gate” to move from one channel to the next, such that...
3) Forces govern channels. There may be opposing psychological forces causing conflict which creates resistance to movement through the channel. Further...
4) There may be several channels that lead to the same end result. And...
5) Different actors may control the channels and act as gatekeepers at different times.
Gatekeeping in the 21st century
More than fifty years after White’s Mr. Gates study, in 2001, Pamela Shoemaker, Martin Eichholz, Eunyi Kim, and Brenda Wrigley studied the forces in news gatekeeping in relation to coverage of Congressional bills. More specifically, they were interested in two hypotheses: 1) the routine gatekeeping force of assessing a bill’s newsworthiness will be related to how prominently a bill is covered. And 2) the individual journalist forces (education, political ideology, work experience, ethnicity, gender, voting behavior) will be related to how prominently a bill is covered. They also predicted that the newsworthiness of a bill would be more important than journalists’ personal characteristics. Surveying both journalists (for their personal characteristics) and editors (for evaluating newsworthiness, Shoemaker and her colleagues found that only newsworthiness had a significant effect on the amount of coverage given to a bill, thus their first hypothesis was supported as well as the idea that newsworthiness would be more important than personal characteristics.
While Shoemaker et al.’s study focused on traditional news rooms, Singer has been interested in how gatekeeping translates to how traditional newspapers use online tools. In both the 2000 and 2004 Presidential elections, she studied how the Internet was changing the process for newspapers, contending that, “the power of gatekeepers seems to diminish in a modern information society. The Internet defies the whole notion of a ‘gate’ and challenges the idea that journalists (or anyone else) can or should limit what passes through it” (p. 265). In the study of the 2004 coverage, Singer posed the following research questions: 1) What did editors of Web sites affiliated with major newspapers see as their goals and their most noteworthy achievements in covering the 2004 political campaign and election? 2) To what extent did these editors relinquish their gatekeeping role by providing opportunities for users to provide or personalize content? And more broadly, 3) In what ways have the views of editors of Web sites affiliated with major newspapers changed since 2000?
Singer found that the content which appears in online editions of newspapers mostly comes from content that appears in the print versions. However, editors were also very proud of the interactive tools on their websites that could not be in the paper. The goal of most editors was after all to inform the public. Further, journalists were beginning to take a step back from their traditional gatekeeping role such that many websites had sections in which journalists provided baseline information and users could manipulate according to their needs and interests like interactive maps, Electoral College scenarios, and ballot building tools based on zip codes. In 2000, editors were likely to boast about how quickly they could publish returns on election night. In 2004, this was no longer the case, as it was standard practice by then. Further, their stated goal for the 2008 election cycle was to let the audience guide the coverage.
Along with Web 2.0 environment, users have begun playing a greater role in producing and (re)distributing online news items via online social networks such as Twitter and Facebook. Shoemaker and Vos (2011) theorized such practice as "audience gatekeeping". According to them (2011), audience gatekeeping is the process in which users “pass along already available news items and comment on them” based on the user’s own set of criteria about the newsworthiness" (p. 113). Kwon et al. (2013) adapted the theory of audience gatekeeping to explore what channels are mainly adopted for Twitter audiences to filter and share news contents. The notion of audience gatekeeping consists with Goode's (2009) discussion on metajournalism, whereby users' role in reprocessing and rebroadcasting the existing online contents are as equally emphasized as users' original creation in nurturing citizen journalism as reshaping the existing hierarchy of journalism system. Kwon et al. (2013) also found that re-processed news items by user-generated content websites, or social media, are more frequently adopted by Twitter users than the direct news times from traditional mass media organizations, confirming the empowering role of ordinary online users in retelling and redistributing news agendas to networked publics.
Toward a theory of network gatekeeping
Karine Barzilai-Nahon has written a number of contemporary pieces on gatekeeping theories between disciplines. In 2008, she proposed a new way of looking at gatekeeping, merging the disciplines’ of communication, information science, and management perspectives into a refined theory of gatekeeping. Traditional mass communication gatekeeping theory has focused on how we get news, however Barzilai-Nahon’s approach applies to all information.
Barzilai-Nahon also adds new terms and redefines old terms in the framework (pp. 1496–1497)
- Gate – “entrance to or exit from a network or its sections.”
- Gatekeeping – “the process of controlling information as it moves through a gate. Activities include among others, selection, addition, withholding, display, channeling, shaping, manipulation, repetition, timing, localization, integration, disregard, and delection of information.”
- Gated – “the entity subjected to gatekeeping”
- Gatekeeping mechanism - “a tool, technology, or methodology used to carry out the process of gatekeeping”
- Network gatekeeper – “an entity (people, organizations, or governments) that has the discretion to exercise gatekeeping through a gatekeeping mechanism in networks and can choose the extent to which to exercise it contingent upon the gated standing.”
This updated look at gatekeeping also poses a number of classifications including the bases for gatekeeping, mechanisms used in network gatekeeping, and types of authority of network gatekeepers.
Additionally, Barzilai-Nahon introduces a typology for the gated. According to her approach, the gated can have four key attributes at different levels that determine how they can interact with the gate. These are (p. 1501):
- Political power in relation to the gatekeeper,
- Information production ability,
- Relationship with the gatekeeper,
- And alternatives in the context of gatekeeping.
A typology of combinations of these characteristics then allows for evaluation of potential interactions between the gatekeeper and the gated based on the number and type of attributes an individual has. Her discussion about "the gated" resonates with audience gatekeeping in that both empowers the message recipients in the process of gatekeeping.
- Barzilai-Nahon, K. (2009). Gatekeeping: A critical review. Annual Review of Information Science and Technology, 43, pp. 433-478.
- Lewin, Kurt. "Forces behind food habits and methods of change". Bulletin of the National Research Council 108: 35–65.
- Shoemaker, Pamela J.; Vos, Tim P. (2009). Gatekeeping Theory. New York: Routledge. ISBN 0415981395.
- DeFleur, Melvin; DeFleur, Margaret (2009). Mass Communication Theories: Explaining Origins, Processes, and Effects. Allyn & Bacon.
- Park, Robert (1922). The Immigrant Press and Its Control. New York: Harper & Brothers.
- Lewin, Kurt (1947). "Frontiers in group dynamics". Human Relations 1: 143–153. doi:10.1177/001872674700100201.
- White, David Manning (1950). "The "gate keeper": A case study in the selection of news". Journalism Quarterly 27: 383–391.
- Shoemaker, Pamela; Eichholz, Martin; Kim, Eunyi; Wrigley, Brenda (2001). "Individual and routine forces in gatekeeping". Journalism & Mass Communication Quarterly 78: 233–246. doi:10.1177/107769900107800202.
- Singer, Jane B. (2003). "Campaign contributions: Online newspaper coverage of Election 2000". Journalism and Mass Communication Quarterly 80: 39–56. doi:10.1177/107769900308000104.
- Singer, Jane B. (2006). "Stepping back from the gate: Online newspaper editors and the co-production of content in Campaign 2004". Journalism and Mass Communication Quarterly 83 (2): 265–280. doi:10.1177/107769900608300203.
- Shoemaker, P. and T. Vos (2009) Gatekeeping Theory. New York: Routledge.
- Kwon, K. H., O. Oh, M. Agrawal, and H. R. Rao (2012) “Audience Gatekeeping in the Twitter Service: An Investigation of Tweets about the 2009 Gaza Conflict”, AIS Transactions on Human-Computer Interaction (4) 4, pp. 212-229.
- Goode, L. (2009) “Social news, citizen journalism, and democracy”, New Media and Society 11 (8), pp. 1287-1305.
- Barzilai-Nahon, Karine (2008). "Toward a Theory of Network Gatekeeping: A Framework for Exploring Information Control". Journal of the American Information Science and Technology 59 (9): 1–20.
- Barzilai-Nahon, Karine (2006). "Gatekeepers, Virtual Communities and their Gated: Multidimensional Tensions in Cyberspace". International Journal of Communications, Law and Policy. Autumn (11).
- Gatekeeping: regulate the flow of information, University of Twente, the Netherlands