Media bias

Media bias is the bias of journalists and news producers within the mass media in the selection of many events and stories that are reported and how they are covered. The term "media bias" implies a pervasive or widespread bias contravening the standards of journalism, rather than the perspective of an individual journalist or article. The direction and degree of media bias in various countries is widely disputed.
Practical limitations to media neutrality include the inability of journalists to report all available stories and facts, and the requirement that selected facts be linked into a coherent narrative. Government influence, including overt and covert censorship, biases the media in some countries, for example China, North Korea and Myanmar. Market forces that result in a biased presentation include the ownership of the news source, concentration of media ownership, the subjective selection of staff, or the preferences of an intended audience.
There are a number of national and international watchdog groups that report on bias of the media.
Types.
The most commonly discussed types of bias occur when the (allegedly partisan) media support or attack a particular political party, candidate, or ideology.
D'Alessio and Allen list three forms of media bias as the most widely studied:
Other common forms of political and non-political media bias include:
Other forms of bias include reporting that favors or attacks a particular race, religion, gender, age, sexual orientation, ethnic group, or even person
History.
Political bias has been a feature of the mass media since its birth with the invention of the printing press. The expense of early printing equipment restricted media production to a limited number of people. Historians have found that publishers often served the interests of powerful social groups.
John Milton's pamphlet "Areopagitica, a Speech for the Liberty of Unlicensed Printing", published in 1644, was one of the first publications advocating freedom of the press.
In the 19th century, journalists began to recognize the concept of unbiased reporting as an integral part of journalistic ethics. This coincided with the rise of journalism as a powerful social force. Even today, though, the most conscientiously objective journalists cannot avoid accusations of bias.
Like newspapers, the broadcast media (radio and television) have been used as a mechanism for propaganda from their earliest days, a tendency made more pronounced by the initial ownership of broadcast spectrum by national governments. Although a process of media deregulation has placed the majority of the western broadcast media in private hands, there still exists a strong government presence, or even monopoly, in the broadcast media of many countries across the globe. At the same time, the concentration of media ownership in private hands, and frequently amongst a comparatively small number of individuals, has also led to accusations of media bias.
There are many examples of accusations of bias being used as a political tool, sometimes resulting in government censorship.
Not all accusations of bias are political. Science writer Martin Gardner has accused the entertainment media of anti-science bias. He claims that television programs such as "The X-Files" promote superstition. In contrast, the Competitive Enterprise Institute, which is funded by businesses, accuses the media of being biased in favor of science and against business interests, and of credulously reporting science that shows that greenhouse gasses cause global warming.
Confirmation bias.
A major problem in studies is confirmation bias. Research into studies of media bias in the United States shows that liberal experimenters tend to get results that say the media has a conservative bias, while conservative experimenters tend to get results that say the media has a liberal bias, and those who do not identify themselves as either liberal or conservative get results indicating little bias, or mixed bias.
The study "A Measure of Media Bias", by political scientist Timothy J. Groseclose of UCLA and economist Jeffrey D. Milyo of the University of Missouri-Columbia, purports to rank news organizations in terms of identifying with liberal or conservative values relative to each other. They used the Americans for Democratic Action (ADA) scores as a quantitative proxy for political leanings of the referential organizations. Thus their definition of "liberal" includes the RAND Corporation, a nonprofit research organization with strong ties to the Defense Department. Their work claims to detect a bias towards liberalism in the American media.
United States political bias.
Media bias in the United States occurs when the media in the United States systematically emphasizes one particular point of view in a manner that contravenes the standards of professional journalism. Claims of media bias in the United States include claims of liberal bias, conservative bias, mainstream bias, corporate bias and activist/cause bias. To combat this, a variety of watchdog groups that attempt to find the facts behind both biased reporting and unfounded claims of bias have been founded. These include:
Research about media bias is now a subject of systematic scholarship in a variety of disciplines.
Scholarly treatment in the United States and United Kingdom.
Media bias is studied at schools of journalism, university departments (including Media studies, Cultural studies and Peace studies) and by independent watchdog groups from various parts of the political spectrum. In the United States, many of these studies focus on issues of a conservative/liberal balance in the media. Other focuses include international differences in reporting, as well as bias in reporting of particular issues such as economic class or environmental interests. Currently, most of these analyses are performed manually, requiring exacting and time-consuming effort. However, an interdisciplinary literature review from 2018 found that automated methods, mostly from computer science and computational linguistics, are available or could with comparably low effort be adapted for the analysis of the various forms of media bias. Employing or adapting such techniques would help to further automate the analyses in the social sciences, such as content analysis and frame analysis.
Martin Harrison's "TV News: Whose Bias?" (1985) criticized the methodology of the Glasgow Media Group, arguing that the GMG identified bias selectively, via their own preconceptions about what phrases qualify as biased descriptions. For example, the GMG sees the word "idle" to describe striking workers as pejorative, despite the word being used by strikers themselves.
Herman and Chomsky (1988) proposed a propaganda model hypothesizing systematic biases of U.S. media from structural economic causes. They hypothesize media ownership by corporations, funding from advertising, the use of official sources, efforts to discredit independent media ("flak"), and "anti-communist" ideology as the filters that bias news in favor of U.S. corporate interests.
Many of the positions in the preceding study are supported by a 2002 study by Jim A. Kuypers: "Press Bias and Politics: How the Media Frame Controversial Issues". In this study of 116 mainstream US papers, including "The New York Times", "the Washington Post", "Los Angeles Times", and the "San Francisco Chronicle", Kuypers found that the mainstream print press in America operate within a narrow range of liberal beliefs. Those who expressed points of view further to the left were generally ignored, whereas those who expressed moderate or conservative points of view were often actively denigrated or labeled as holding a minority point of view. In short, if a political leader, regardless of party, spoke within the press-supported range of acceptable discourse, he or she would receive positive press coverage. If a politician, again regardless of party, were to speak outside of this range, he or she would receive negative press or be ignored. Kuypers also found that the liberal points of view expressed in editorial and opinion pages were found in hard news coverage of the same issues. Although focusing primarily on the issues of race and homosexuality, Kuypers found that the press injected opinion into its news coverage of other issues such as welfare reform, environmental protection, and gun control; in all, cases favoring a liberal point of view. 
Henry Silverman (2011) of Roosevelt University analyzed a sample of fifty news-oriented articles on the Middle East conflict published on the Reuters.com websites for the use of classic propaganda techniques, logical fallacies and violations of the Reuters Handbook of Journalism, a manual of guiding ethical principles for the company's journalists. Across the articles, over 1,100 occurrences of propaganda, fallacies and handbook violations in 41 categories were identified and classified. In the second part of the study, a group of thirty-three university students were surveyed, before and after reading the articles, to assess their attitudes and motivation to support one or the other belligerent parties in the Middle East conflict, i.e., the Palestinians/Arabs or the Israelis. The study found that on average, subject sentiment shifted significantly following the readings in favor of the Arabs and that this shift was associated with particular propaganda techniques and logical fallacies appearing in the stories. Silverman inferred from the evidence that Reuters engages in systematically biased storytelling in favor of the Arabs/Palestinians and is able to influence audience affective behavior and motivate direct action along the same trajectory.
Studies reporting perceptions of bias in the media are not limited to studies of print media. A joint study by the Joan Shorenstein Center on Press, Politics and Public Policy at Harvard University and the Project for Excellence in Journalism found that people see media bias in television news media such as CNN. Although both CNN and Fox were perceived in the study as not being centrist, CNN was perceived as being more liberal than Fox. Moreover, the study's findings concerning CNN's perceived bias are echoed in other studies. There is also a growing economics literature on mass media bias, both on the theoretical and the empirical side. On the theoretical side the focus is on understanding to what extent the political positioning of mass media outlets is mainly driven by demand or supply factors. This literature is surveyed by Andrea Prat of Columbia University and David Stromberg of Stockholm University.
According to Dan Sutter of the University of Oklahoma, a systematic liberal bias in the U.S. media could depend on the fact that owners and/or journalists typically lean to the left.
Along the same lines, David Baron of Stanford GSB presents a game-theoretic model of mass media behaviour in which, given that the pool of journalists systematically leans towards the left or the right, mass media outlets maximise their profits by providing content that is biased in the same direction. They can do so, because it is cheaper to hire journalists who write stories that are consistent with their political position. A concurrent theory would be that supply and demand would cause media to attain a neutral balance because consumers would of course gravitate towards the media they agreed with. This argument fails in considering the imbalance in self-reported political allegiances by journalists themselves, that distort any market analogy as regards offer: (..) "Indeed, in 1982, 85 percent of Columbia Graduate School of Journalism students identified themselves as liberal, versus 11 percent conservative"" (Lichter, Rothman, and Lichter 1986: 48), quoted in Sutter, 2001.
This same argument would have news outlets in equal numbers increasing profits of a more balanced media far more than the slight increase in costs to hire unbiased journalists, notwithstanding the extreme rarity of self-reported conservative journalists (Sutton, 2001).
As mentioned above, Tim Groseclose of UCLA and Jeff Milyo of the University of Missouri at Columbia use think tank quotes, in order to estimate the relative position of mass media outlets in the political spectrum. The idea is to trace out which think tanks are quoted by various mass media outlets within news stories, and to match these think tanks with the political position of members of the U.S. Congress who quote them in a non-negative way. Using this procedure, Groseclose and Milyo obtain the stark result that all sampled news providers -except Fox News' Special Report and the Washington Times- are located to the left of the average Congress member, i.e. there are signs of a liberal bias in the US news media.
The methods Groseclose and Milyo used to calculate this bias have been criticized by Mark Liberman, a professor of Linguistics at the University of Pennsylvania. Liberman concludes by saying he thinks "that many if not most of the complaints directed against G&M are motivated in part by ideological disagreement – just as much of the praise for their work is motivated by ideological agreement. It would be nice if there were a less politically fraught body of data on which such modeling exercises could be explored."
Sendhil Mullainathan and Andrei Shleifer of Harvard University construct a behavioural model, which is built around the assumption that readers and viewers hold beliefs that they would like to see confirmed by news providers. When news customers share common beliefs, profit-maximizing media outlets find it optimal to select and/or frame stories in order to pander to those beliefs. On the other hand, when beliefs are heterogeneous, news providers differentiate their offer and segment the market, by providing news stories that are slanted towards the two extreme positions in the spectrum of beliefs.
Matthew Gentzkow and Jesse Shapiro of Chicago GSB present another demand-driven theory of mass media bias. If readers and viewers have a priori views on the current state of affairs and are uncertain about the quality of the information about it being provided by media outlets, then the latter have an incentive to slant stories towards their customers' prior beliefs, in order to build and keep a reputation for high-quality journalism. The reason for this is that rational agents would tend to believe that pieces of information that go against their prior beliefs in fact originate from low-quality news providers.
Given that different groups in society have different beliefs, priorities, and interests, to which group would the media tailor its bias? David Stromberg constructs a demand-driven model where media bias arises because different audiences have different effects on media profits. Advertisers pay more for affluent audiences and media may tailor content to attract this audience, perhaps producing a right-wing bias. On the other hand, urban audiences are more profitable to newspapers because of lower delivery costs. Newspapers may for this reason tailor their content to attract the profitable predominantly liberal urban audiences. Finally, because of the increasing returns to scale in news production, small groups such as minorities are less profitable. This biases media content against the interest of minorities.
Steve Ansolabehere, Rebecca Lessem and Jim Snyder of the Massachusetts Institute of Technology analyze the political orientation of endorsements by U.S. newspapers. They find an upward trend in the average propensity to endorse a candidate, and in particular an incumbent one. There are also some changes in the average ideological slant of endorsements: while in the 1940s and in the 1950s there was a clear advantage to Republican candidates, this advantage continuously eroded in subsequent decades, to the extent that in the 1990s the authors find a slight Democratic lead in the average endorsement choice.
John Lott and Kevin Hassett of the American Enterprise Institute study the coverage of economic news by looking at a panel of 389 U.S. newspapers from 1991 to 2004, and from 1985 to 2004 for a subsample comprising the top 10 newspapers and the Associated Press. For each release of official data about a set of economic indicators, the authors analyze how newspapers decide to report on them, as reflected by the tone of the related headlines. The idea is to check whether newspapers display some kind of partisan bias, by giving more positive or negative coverage to the same economic figure, as a function of the political affiliation of the incumbent president. Controlling for the economic data being released, the authors find that there are between 9.6 and 14.7 percent fewer positive stories when the incumbent president is a Republican.
Riccardo Puglisi of the Massachusetts Institute of Technology looks at the editorial choices of the "New York Times" from 1946 to 1997. He finds that the "Times" displays Democratic partisanship, with some watchdog aspects. This is the case, because during presidential campaigns the "Times" systematically gives more coverage to Democratic topics of civil rights, health care, labor and social welfare, but only when the incumbent president is a Republican. These topics are classified as Democratic ones, because Gallup polls show that on average U.S. citizens think that Democratic candidates would be better at handling problems related to them. According to Puglisi, in the post-1960 period the "Times" displays a more symmetric type of watchdog behaviour, just because during presidential campaigns it also gives more coverage to the typically Republican issue of Defense when the incumbent president is a Democrat, and less so when the incumbent is a Republican.
Alan Gerber and Dean Karlan of Yale University use an experimental approach to examine not whether the media are biased, but whether the media influence political decisions and attitudes. They conduct a randomized control trial just prior to the November 2005 gubernatorial election in Virginia and randomly assign individuals in Northern Virginia to (a) a treatment group that receives a free subscription to the Washington Post, (b) a treatment group that receives a free subscription to the Washington Times, or (c) a control group. They find that those who are assigned to the Washington Post treatment group are eight percentage points more likely to vote for the Democrat in the elections. The report also found that "exposure to either newspaper was weakly linked to a movement away from the Bush administration and Republicans."
A self-described "progressive" media watchdog group, Fairness and Accuracy in Reporting (FAIR), in consultation with the Survey and Evaluation Research Laboratory at Virginia Commonwealth University, sponsored a 1998 survey in which 141 Washington bureau chiefs and Washington-based journalists were asked a range of questions about how they did their work and about how they viewed the quality of media coverage in the broad area of politics and economic policy. "They were asked for their opinions and views about a range of recent policy issues and debates. Finally, they were asked for demographic and identifying information, including their political orientation". They then compared to the same or similar questions posed with "the public" based on Gallup, and Pew Trust polls. Their study concluded that a majority of journalists, although relatively liberal on social policies, were significantly to the right of the public on economic, labor, health care and foreign policy issues.
This study continues: "we learn much more about the political orientation of news content by looking at sourcing patterns rather than journalists' personal views. As this survey shows, it is government officials and business representatives to whom journalists "nearly always" turn when covering economic policy. Labor representatives and consumer advocates were at the bottom of the list. This is consistent with earlier research on sources. For example, analysts from the non-partisan Brookings Institution and from conservative think tanks such as the Heritage Foundation and the American Enterprise Institute are those most quoted in mainstream news accounts.
In direct contrast to the FAIR survey, in 2014, media communication researcher Jim A. Kuypers published a 40-year longitudinal, aggregate study of the political beliefs and actions of American journalists. In every single category, for instance, social, economic, unions, health care, and foreign policy, he found that nationwide, print and broadcast journalists and editors as a group were "considerably" to the political left of the majority of Americans, and that these political beliefs found their way into news stories. Kuypers concluded, "Do the political proclivities of journalists influence their interpretation of the news? I answer that with a resounding, yes. As part of my evidence, I consider testimony from journalists themselves. ... [A] solid majority of journalists do allow their political ideology to influence their reporting."
Jonathan M. Ladd, who has conducted intensive studies of media trust and media bias, concluded that the primary cause of belief in media bias is media telling their audience that particular media are biased. People who are told that a medium is biased tend to believe that it is biased, and this belief is unrelated to whether that medium is actually biased or not. The only other factor with as strong an influence on belief that media is biased is extensive coverage of celebrities. A majority of people see such media as biased, while at the same time preferring media with extensive coverage of celebrities.
Starting in 2017, the Knight Foundation and Gallup conducted research to try to understand the effect of reader bias on the reader's perception of news source bias. They created the NewsLens site to present news from a variety of sources without labeling where the article came from. Their research showed that those with more extreme political views tend to provide more biased ratings of news. NewsLens became generally available in 2020, with the goals of expanding on the research and helping the US public to read and share news with less bias. However, , the platform was closed.
Efforts to correct bias.
A technique used to avoid bias is the "point/counterpoint" or "round table", an adversarial format in which representatives of opposing views comment on an issue. This approach theoretically allows diverse views to appear in the media. However, the person organizing the report still has the responsibility to choose people who really represent the breadth of opinion, to ask them non-prejudicial questions, and to edit or arbitrate their comments fairly. When done carelessly, a point/counterpoint can be as unfair as a simple biased report, by suggesting that the "losing" side lost on its merits. The impact of such techniques to oppose different viewpoints also shows mixed effects in ongoing research
Using this format can also lead to accusations that the reporter has created a misleading appearance that viewpoints have equal validity (sometimes called "false balance"). This may happen when a taboo exists around one of the viewpoints, or when one of the representatives habitually makes claims that are easily shown to be inaccurate.
One such allegation of misleading balance came from Mark Halperin, political director of ABC News. He stated in an internal e-mail message that reporters should not "artificially hold George W. Bush and John Kerry 'equally' accountable" to the public interest, and that complaints from Bush supporters were an attempt to "get away with ... renewed efforts to win the election by destroying Senator Kerry." When the conservative web site the Drudge Report published this message, many Bush supporters viewed it as "smoking gun" evidence that Halperin was using ABC to propagandize against Bush to Kerry's benefit, by interfering with reporters' attempts to avoid bias. An academic content analysis of election news later found that coverage at ABC, CBS, and NBC was more favorable toward Kerry than Bush, while coverage at Fox News Channel was more favorable toward Bush.
Scott Norvell, the London bureau chief for Fox News, stated in a May 20, 2005 interview with the "Wall Street Journal" that:
"Even we at Fox News manage to get some lefties on the air occasionally, and often let them finish their sentences before we club them to death and feed the scraps to Karl Rove and Bill O'Reilly. And those who hate us can take solace in the fact that they aren't subsidizing Bill's bombast; we payers of the BBC license fee don't enjoy that peace of mind.<br>
Fox News is, after all, a private channel and our presenters are quite open about where they stand on particular stories. That's our appeal. People watch us because they know what they are getting. The Beeb's (British Broadcasting Corporation) (BBC) institutionalized leftism would be easier to tolerate if the corporation was a little more honest about it".
Another technique used to avoid bias is disclosure of affiliations that may be considered a possible conflict of interest. This is especially apparent when a news organization is reporting a story with some relevancy to the news organization itself or to its ownership individuals or conglomerate. Often this disclosure is mandated by the laws or regulations pertaining to stocks and securities. Commentators on news stories involving stocks are often required to disclose any ownership interest in those corporations or in its competitors.
In rare cases, a news organization may dismiss or reassign staff members who appear biased. This approach was used in the Killian documents affair and after Peter Arnett's interview with the Iraqi press. This approach is presumed to have been employed in the case of Dan Rather over a story that he ran on "60 Minutes" in the month prior to the 2004 election that attempted to impugn the military record of George W. Bush by relying on allegedly fake documents that were provided by Bill Burkett, a retired Lieutenant Colonel in the Texas Army National Guard.
Finally, some countries have laws enforcing balance in state-owned media. Since 1991, the CBC and Radio Canada, its French language counterpart, are governed by the Broadcasting Act. This act states, among other things:
...the programming provided by the Canadian broadcasting system should:
Besides these manual approaches, several (semi-)automated approaches have been developed by social scientists and computer scientists. These approaches identify differences in news coverage, which potentially resulted from media bias, by analyzing the text and meta data, such as author and publishing date. For instance, NewsCube is a news aggregator that extracts key phrases that describe a topic differently. Other approaches make use of text- and meta-data, e.g., matrix-based news aggregation spans a matrix over two dimensions, such as "publisher countries" (in which articles have been published) and "mentioned countries" (on which country an article reports). As a result, each cell contains only articles that have been published in one country and that report on another country. Particularly in international news topics, matrix-based news aggregation helps to reveal differences in media coverage between the involved countries. Attempts have also been made to utilize machine-learning to analyze the bias of text.
National and ethnic viewpoint.
Many news organizations reflect, or are perceived to reflect in some way, the viewpoint of the geographic, ethnic, and national population that they primarily serve. Media within countries are sometimes seen as being sycophantic or unquestioning about the country's government.
Western media are often criticized in the rest of the world (including eastern Europe, Asia, Africa, and the Middle East) as being pro-Western with regard to a variety of political, cultural and economic issues. Al Jazeera is frequently criticized both in the West and in the Arab world.
The Israeli–Palestinian conflict and wider Arab–Israeli issues are a particularly controversial area, and nearly all coverage of any kind generates accusation of bias from one or both sides. This topic is covered in a separate article.
Anglophone bias in the world media.
It has been observed that the world's principal suppliers of news, the news agencies, and the main buyers of news are Anglophone corporations and this gives an Anglophone bias to the selection and depiction of events. Anglophone definitions of what constitutes news are paramount; the news provided originates in Anglophone capitals and responds first to their own rich domestic markets.
Despite the plethora of news services, most news printed and broadcast throughout the world each day comes from only a few major agencies, the three largest of which are the Associated Press, Reuters and Agence France-Presse. Although these agencies are 'global' in the sense of their activities, they each retain significant associations with particular nations, namely the United States (AP), the United Kingdom (Reuters) and France (AFP). Chambers and Tinckell suggest that the so-called global media are agents of Anglophone values which privilege norms of 'competitive individualism, "laissez-faire" capitalism, parliamentary democracy and consumerism.' They see the presentation of the English language as international as a further feature of Anglophone dominance.
Religious bias.
The media are often accused of bias favoring a particular religion or of bias against a particular religion. In some countries, only reporting approved by a state religion is permitted. In other countries, derogatory statements about any belief system are considered hate crimes and are illegal.
According to the Encyclopedia of Social Work (19th edition), the news media play an influential role in the general public's perception of cults. As reported in several studies, the media have depicted cults as problematic, controversial, and threatening from the beginning, tending to favor sensationalistic stories over balanced public debates. It furthers the analysis that media reports on cults rely heavily on police officials and cult "experts" who portray cult activity as dangerous and destructive, and when divergent views are presented, they are often overshadowed by horrific stories of ritualistic torture, sexual abuse, mind control, and other such practices. Furthermore, unfounded allegations, when proved untrue, receive little or no media attention.
In 2012, "Huffington Post", columnist Jacques Berlinerblau argued that secularism has often been misinterpreted in the media as another word for atheism, stating that: "Secularism must be the most misunderstood and mangled ism in the American political lexicon. Commentators on the right and the left routinely equate it with Stalinism, Nazism and Socialism, among other dreaded isms. In the United States, of late, another false equation has emerged. That would be the groundless association of secularism with atheism. The religious right has profitably promulgated this misconception at least since the 1970s."
According to Stuart A. Wright, there are six factors that contribute to media bias against minority religions: first, the knowledge and familiarity of journalists with the subject matter; second, the degree of cultural accommodation of the targeted religious group; third, limited economic resources available to journalists; fourth, time constraints; fifth, sources of information used by journalists; and finally, the front-end/back-end disproportionality of reporting. According to Yale Law professor Stephen Carter, "it has long been the American habit to be more suspicious of—and more repressive toward—religions that stand outside the mainline Protestant-Roman Catholic-Jewish troika that dominates America's spiritual life." As for front-end/back-end disproportionality, Wright says: "news stories on unpopular or marginal religions frequently are predicated on unsubstantiated allegations or government actions based on faulty or weak evidence occurring at the front-end of an event. As the charges weighed in against material evidence, these cases often disintegrate. Yet rarely is there equal space and attention in the mass media given to the resolution or outcome of the incident. If the accused are innocent, often the public is not made aware."
Social media bias.
One of the hotbeds of political bias is social media. Within the United States, Pew Research Center reported that 64% of Americans believed that social media had a toxic effect on our society and culture in July 2020. Only 10% of Americans believed that it had a positive effect on society. Even still, 72% of US Adults had at least one social media account in 2019, and 65% of Americans believe that social media is an effective way to reach out to politicians. Some of the main concerns with social media lie with the spread of deliberately false or misinterpreted information and the spread of hate and extremism. Social scientist experts explain the growth of misinformation and hate as a result of the increase in echo chambers.
Fueled by confirmation bias, online echo chambers allow users to be steeped within their own ideology. Because social media is tailored to your interests and your selected friends, it is an easy outlet for political echo chambers. Another Pew Research poll in 2019 showed that 28% of US adults "often" find their news through social media, and 55% of US adults get their news from social media either "often" or "sometimes". Additionally, more people are reported as going to social media for their news as the Coronavirus has restricted politicians to online campaigns and social media live streams. GCF Global encourages online users to avoid echo chambers by interacting with different people and perspectives along with avoiding the temptation of confirmation bias.
How people view media.
In 1997, two-thirds (67%) said agreed with the statement: "In dealing with political and social issues, news organizations tend to favor one side." That was up 14 points from 53 percent who gave that answer in 1985. Those who believed the media "deal fairly with all sides" fell from 34 percent to 27 percent. "In one of the most telling complaints, a majority (54%) of Americans believe the news media gets in the way of society solving its problems," Pew reported. Republicans "are more likely to say news organizations favor one side than are Democrats or independents (77 percent vs. 58 percent and 69 percent, respectively)."
The percentage who felt "news organizations get the facts straight" fell from 55 percent to 37 percent.
Role of language.
Bias is often reflected in which language is used, and in the way that language is used. Mass media has a worldwide reach, but must communicate with each linguistic group in some language they understand. The use of language may be neutral, or may attempt to be as neutral as possible, using careful translation and avoiding culturally charged words and phrases. Or it may be intentionally or accidentally biased, using mistranslations and trigger words targeting particular groups.
For example, in Bosnia and Herzegovina there are three mutually intelligible languages, Bosnian, Croatian, and Serbian. Media that try to reach as large an audience as possible use words common to all three languages. Media that want to target just one group may choose words that are unique to that group. In the United States, while most media is in English, in the 2020 election both major political parties used Spanish language advertising to reach out to Hispanic voters. Al Jazeera originally used Arabic, to reach its target audience, but in 2003 launched Al Jazeera English to broaden that audience.
Attempts to use language designed to appeal to a particular cultural group can backfire, as when Kimberly Guilfoyle, speaking at the Republican National Convention in 2020, said she was proud that her mother was an immigrant from Puerto Rico. Puerto Ricans were quick to point out that they are born American citizens, and are not immigrants. 
There are also false flag broadcasts, that pretend to be favoring one group, while using language deliberately chosen to anger the target audience. 
Language may also introduce a more subtle form of bias. The selection of metaphors and analogies, or the inclusion of personal information in one situation but not another can introduce bias, such as a gender bias. Use of a word with positive or negative connotations rather than a more neutral synonym can form a biased picture in the audience's mind. For example, it makes a difference whether the media calls a group "terrorists" or "freedom fighters" or "insurgents". A 2005 memo to the staff of the CBC states:
In a widely criticized episode, initial online BBC reports of the 7 July 2005 London bombings identified the perpetrators as terrorists, in contradiction to the BBC's internal policy. But by the next day, journalist Tom Gross noted that the online articles had been edited, replacing "terrorists" by "bombers". In another case, March 28, 2007, the BBC paid almost $400,000 in legal fees in a London court to keep an internal memo dealing with alleged anti-Israeli bias from becoming public. The BBC has been accused of having a pro-Israel bias.
Other influences.
The apparent bias of media is not always specifically political in nature. The news media tend to appeal to a specific audience, which means that stories that affect a large number of people on a global scale often receive less coverage in some markets than local stories, such as a public school shooting, a celebrity wedding, a plane crash, a "missing white woman", or similarly glamorous or shocking stories. For example, the deaths of millions of people in an ethnic conflict in Africa might be afforded scant mention in American media, while the shooting of five people in a high school is analyzed in depth. Bias is also known to exist in sports broadcasting; in the United States, broadcasters tend to favor teams on the East Coast, teams in major markets, older and more established teams and leagues, teams based in their respective country (in international sport) and teams that include high-profile celebrity athletes. The reason for these types of bias is a function of what the public wants to watch and/or what producers and publishers believe the public wants to watch.
Bias has also been claimed in instances referred to as conflict of interest, whereby the owners of media outlets have vested interests in other commercial enterprises or political parties. In such cases in the United States, the media outlet is required to disclose the conflict of interest.
However, the decisions of the editorial department of a newspaper and the corporate parent frequently are not connected, as the editorial staff retains freedom to decide what is covered as well as what is not. Biases, real or implied, frequently arise when it comes to deciding what stories will be covered and who will be called for those stories.
Accusations that a source is biased, if accepted, may cause media consumers to distrust certain kinds of statements, and place added confidence on others.