Misinformation is false, inaccurate, or misleading information that is communicated regardless of an intention to deceive. Examples of misinformation are false rumors, insults, and pranks. Disinformation is a subset of misinformation that is deliberately deceptive, e.g., malicious hoaxes, spearphishing, and computational propaganda. The principal effect of misinformation is to elicit fear and suspicion among a population. News parody or satire can become misinformation if it is believed to be credible and communicated as if it were true. The words "misinformation" and "disinformation" have often been associated with the concept of "fake news", which some scholars define as "fabricated information that mimics news media content in form but not in organizational process or intent".
The history of misinformation, along with that of disinformation and propaganda, is part of the history of mass communication. Early examples cited in a 2017 article by Robert Darnton are the insults and smears spread among political rivals in Imperial and Renaissance Italy in the form of "pasquinades". These are anonymous and witty verse named for the Pasquino piazza and "talking statue" in Rome, and in pre-revolutionary France as "canards", or printed broadsides that sometimes included an engraving to help convince readers to take their wild tales seriously.
The spread in Europe and North America of Johannes Gutenberg's mechanized printing press increased the opportunities to spread English-language misinformation. In 1835, the New York Sun published the first large-scale news hoax, known as the "Great Moon Hoax". This was a series of six articles claiming to describe life on the Moon, "complete with illustrations of humanoid bat-creatures and bearded blue unicorns". The fast pace and sometimes strife-filled work of mass-producing news broadsheets also led to copies with factual errors and mistakes, such as the Chicago Tribune's infamous 1948 headline "Dewey Defeats Truman".
In the so-called Information Age, social networking sites have become a notable agent for the spread of misinformation, fake news, and propaganda. Misinformation on social media spreads quickly in comparison to traditional media because of the lack of regulation and examination required before posting. These sites provide users with the capability to spread information quickly to other users without requiring the permission of a gatekeeper such as an editor, who might otherwise require confirmation of its truth before allowing its publication. Journalists today are criticized for helping to spread false information on these social platforms, but research such as that from Starbird et al. and Arif et al. shows they also play a role in curbing the spread of misinformation on social media through debunking and denying false rumors.
Information conveyed as credible but later amended can affect people's memory and reasoning after retraction. Misinformation differs from concepts like rumors because misinformation is inaccurate information that has previously been disproved. According to Anne Mintz, editor of Web of Deception: Misinformation on the Internet, the best ways to determine whether information is factual is to use common sense. Mintz advises that the reader check whether the information makes sense and whether the founders or reporters of the websites that are spreading the information are biased or have an agenda. Professional journalists and researchers look at other sites (particularly verified sources like news channels) for that information, as it might be reviewed by multiple people and heavily researched, providing more concrete details.
Martin Libicki, author of Conquest In Cyberspace: National Security and Information Warfare, noted that the trick to working with misinformation is the idea that readers must have a balance of what is correct or incorrect. Readers cannot be gullible but also should not be paranoid that all information is incorrect. There is always a chance that even readers who have this balance will believe an error to be true or that they will disregard factual information as incorrect.
According to research, the factors that lead to recognizing misinformation is the amount of education a person has and the information literacy, or media literacy, they have. This means if a person is more familiar with the content and process of how the information is researched and presented, or is better at critically evaluating information of any source, then they are more likely to identify misinformation. Increasing literacy may not lead to improved ability to detect misinformation, as a certain level of literacy could be used to "justify belief in misinformation". Further research reveal that content descriptors can have a varying effect in people in detecting misinformation.
Prior research suggests it can be very difficult to undo the effects of misinformation once individuals believe it to be true and fact checking can even backfire. An individual may have a desire to reach a certain conclusion, causing them to accept information that supports that conclusion. This is known as Motivated reasoning, and can cause individuals to accept misinformation as true. Individuals create mental models and schemas that are used to understand physical and social environments. Misinformation that becomes incorporated into a mental model, especially for long periods of time, will be more difficult to address as individuals prefer to have a complete mental model. In this instance, it is necessary to correct the misinformation by not only refuting it, but also by providing accurate information that can also function in the mental model. When attempting to correct misinformation, it is important to consider previous research which has identified effective and ineffective strategies. Simply providing the corrected information is not enough to correct any effects of misinformation, and it may even have a negative effect. Because of the familiarity heuristic--information that is familiar is more likely to be believed to be true--corrective messages which contain a repetition of the original misinformation may result in an increase in familiarity and cause a backfire effect
Factors which contribute to the effectiveness of a corrective message are an individual's mental model, an individuals worldview beliefs, repetition of the misinformation, time-lag between misinformation and correction, credibility of the source and relative coherency of the misinformation and corrective message. Corrective messages will be more effective when they are coherent and/or consistent with the target audience's worldview beliefs. They will be less effective when misinformation is believed to come from a credible source, is repeated prior to correction (even if the repetition occurs in the process of debunking), and/or when there is a time-lag between the misinformation exposure and corrective message Additionally, corrective messages delivered by the original source of the misinformation will be more effective.
A suggested solution that would focus on primary prevention of misinformation is the use of a distributed consensus mechanism to validate the accuracy of claims, with appropriate flagging or removal of content that is determined to be false or misleading. Another approach to correcting misinformation is to "inoculate" against it by delivering misinformation in a weakened form by warning of the dangers of the misinformation and including counterarguments showing the misleading techniques at work in the misinformation. One way to apply this approach is to use parallel argumentation, in which the flawed logic is transferred to a parallel, if extreme or absurd, situation. This approach exposes bad logic without the need for complicated explanations.
Flagging or eliminating news media containing false statements using algorithmic fact checkers is becoming the front line in the battle against the spread of misinformation. Computer programs that automatically detect misinformation are still just beginning to emerge, but similar algorithms are already in place with Facebook and Google. Algorithms detect and alert Facebook users that what they are about to share is likely false, hoping to reduce the chances of the user sharing. Likewise, Google provides supplemental information pointing to fact check websites in response to its users searching controversial search terms.
Historically, people have relied on journalists and other information professionals to relay facts and truths. Many different things cause miscommunication but the underlying factor is information literacy. Information is distributed by various means, and because of this it is often hard for users to ask questions of the credibility of what they are seeing. Many online sources of misinformation use techniques to fool users into thinking their sites are legitimate and the information they generate is factual. Often misinformation can be politically motivated. Websites such as USConservativeToday.com have previously posted false information for political and monetary gain. Another role misinformation serves is to distract the public eye from negative information about a given person and/or bigger issues of policy, which as a result can go unremarked with the public preoccupied with fake-news. In addition to the sharing of misinformation for political and monetary gain it is also spread unintentionally. Advances in digital media have made it easier to share information, although it is not always accurate. The next sections discuss the role social media has in distributing misinformation, the lack of internet gatekeepers, implications of censorship in combating misinformation, inaccurate information from media sources, and competition in news and media.
Social Media can be a cause of misinformation. Users sometimes unknowingly share false information. The rapid sharing of information on social media sometimes causes misinformation. Users share information without first checking the legitimacy of the information they have found. This often happens by the simple share of a post.
Social media platforms offer a rich ground for the spread of misinformation. The exact sharing and motivation behind why misinformation spreads through social media so easily remains unknown. A 2018 study of Twitter determined that, compared to accurate information, false information spread significantly faster, further, deeper, and more broadly. Combating its spread is difficult for two reasons: the profusion of information sources, and the generation of "echo chambers". The profusion of information sources makes the reader's task of weighing the reliability of information more challenging, heightened by the untrustworthy social signals that go with such information. The inclination of people to follow or support like-minded individuals leads to the formation of echo chambers and filter bubbles. With no differing information to counter the untruths or the general agreement within isolated social clusters, some writers argue the outcome is a dearth, and worse, the absence of a collective reality, some writers argue. Although social media sites have changed their algorithms to prevent the spread of fake news, the problem still exists. Furthermore, research has shown that while people may know what the scientific community has proved as a fact, they may still refuse to accept it as such.
Misinformation thrives in a social media landscape frequently used and spread by college students. This can be supported by scholars such as Ghosh and Scott(2018), who indicated that misinformation is "becoming unstoppable". It has also been observed that misinformation and disinformation come back, multiple times on social media sites. A research study watched the process of thirteen rumors appearing on Twitter and noticed that eleven of those same stories resurfaced multiple times, after much time had passed.
Another reason that misinformation spreads on social media is from the users themselves. In a study, it was shown that the most common reasons that Facebook users were sharing misinformation for social motivated reasons, rather than taking the information seriously. Although users may not be spreading false information for malicious reasons, the misinformation is still being spread across the internet. A research study shows that misinformation that is introduced through a social format influences individuals drastically more than misinformation delivered non-socially.
Twitter is one of the most concentrated platforms for engagement with political fake news. 80% of fake news sources are shared by 0.1% of users, who are "super-sharers". Older, more conservative social users are also more likely to interact with fake news.Over 70% of adults in the United States have Facebook accounts, and 70% of those with accounts visit the site daily. On Facebook, adults older than 65 were seven times more likely to share fake news than adults ages 18–29. Another source of misinformation on Twitter is bots. Bots share stories that contain misinformation. Some misinformation, especially surrounding climate change, is centered around bots on twitter sharing stories. Facebook has taken measures to top the spread of misinformation, like flagging posts that may contain fake news. Since Facebook implemented this change, the misinformation appearing on Facebook has dropped, but is still present. 
There is spontaneous misinformation on social media that usually occurs from users sharing posts from friends or other mutual followers. These posts are often shred from someone the sharer believes they can trust. Other misinformation is created and spread with malicious intent. Sometimes to cause anxiety, other times to deceive audiences.  There are times when rumors are created with malicious intent, but shared by unknowing users.
Social media maybe the way to correct misinformation. With the large audiences that can be reached, and the experts on various subjects on social media, it may be the key in correcting misinformation. 
Because of the decentralized nature and structure of the Internet, writers can easily publish content without being required to subject it to peer review, prove their qualifications, or provide backup documentation. Whereas a book found in a library generally has been reviewed and edited by a second person, Internet sources cannot be assumed to be vetted by anyone other than their authors. They may be produced and posted as soon as the writing is finished. In addition, the presence of trolls and bots used to spread willful misinformation has been a problem for social media platforms. As many as 60 million trolls could be actively spreading misinformation on Facebook.
Social media sites such as Facebook and Twitter have found themselves defending accusations of censorship for taking down misinformation. In July 2020, a video showing Dr. Stella Immanuel claiming hydroxychloroquine as an effective cure to coronavirus went viral . In the video, Immanuel suggest that there is no need for masks, school closures, or any kind of economic shut down; attesting that this cure she speaks of is highly effective in treating those infected with the virus. The video was shared 600,000 times and received nearly 20 million views on Facebook before it was taken down for violating community guidelines on spreading misinformation. The video was also taken down on Twitter overnight, but not before President Donald Trump shared it to his page, which is followed by over 85 million Twitter users. NIAID director Dr. Anthony Fauci and members of the World Health Organization (WHO) quickly discredited the video citing larger scale studies of hydroxychloroquine showing it is not an effective treatment of COVID-19, and the FDA cautioned against using it to treat Covid patients following evidence of serious heart problems arising in patients that have taken the drug. Facebook and Twitter alike have policies in place to combat misinformation regarding COVID-19, and the social media platforms were swift with action to back up their respective policies.
A Gallup poll made public in 2016 found that only 32% of Americans trust the mass media "to report the news fully, accurately and fairly", the lowest number in the history of that poll. An example of bad information from media sources that led to the spread of misinformation occurred in November 2005, when Chris Hansen on Dateline NBC made a claim that law enforcement officials estimate 50,000 predators are online at any moment. Afterwards, the U.S. attorney general at the time, Alberto Gonzales, repeated the claim. However, the number that Hansen used in his reporting had no backing. Hansen said he received the information from Dateline expert Ken Lanning, but Lanning admitted that he made up the number 50,000 because there was no solid data on the number. According to Lanning, he used 50,000 because it sounds like a real number, not too big and not too small, and referred to it as a "Goldilocks number". Reporter Carl Bialik says that the number 50,000 is used often in the media to estimate numbers when reporters are unsure of the exact data.
Because news organizations and websites hotly compete for viewers, there is a need for great efficiency in releasing stories to the public. The news media landscape in the 1970s offered American consumers access to a limited, but overall consistent and trusted selection of news offerings, where as today consumers are confronted with an overabundance of voices online. This explosion of consumer choice when it comes to news media allows the consumer to pick and choose a news source that hits their preferred agenda, which consequently increases the likelihood that they are misinformed. 47% of Americans reported social media as their main news source in 2017 as opposed to traditional news sources. News media companies broadcast stories 24 hours a day, and break the latest news in hopes of taking audience share from their competitors. News is also produced at a pace that does not always allow for fact-checking, or for all of the facts to be collected or released to the media at one time, letting readers or viewers insert their own opinions, and possibly leading to the spread of misinformation.
Misinformation can affect all aspects of life. Allcott, Gentzkow and Yu (2019:6) concur that diffusion of misinformation through social media is a potential threat to democracy and broader society. The effects of misinformation can lead to the accurateness about information and details of the occurrence to decline. When eavesdropping on conversations, one can gather facts that may not always be true, or the receiver may hear the message incorrectly and spread the information to others. On the Internet, one can read content that is stated to be factual but that may not have been checked or may be erroneous. In the news, companies may emphasize the speed at which they receive and send information but may not always be correct in the facts. These developments contribute to the way misinformation will continue to complicate the public's understanding of issues and to serve as a source for belief and attitude formation.
In regards to politics, some view being a misinformed citizen as worse than being an uninformed citizen. Misinformed citizens can state their beliefs and opinions with confidence and in turn affect elections and policies. This type of misinformation comes from speakers not always being upfront and straightforward, yet may appear both "authoritative and legitimate" on the surface. When information is presented as vague, ambiguous, sarcastic, or partial, receivers are forced to piece the information together and make assumptions about what is correct. Aside from political propaganda, misinformation can also be employed in industrial propaganda. Using tools such as advertising, a company can undermine reliable evidence or influence belief through concerted misinformation campaign. For instance, tobacco companies employed misinformation in the second half of the twentieth century to diminish the reliability of studies that demonstrated the link between smoking and lung cancer. In the medical field, misinformation can immediately lead to life endangerment as seen in the case of the public's negative perception towards vaccines or the use of herbs instead of medicines to treat diseases. In regards to the COVID-19 pandemic, the spread of misinformation has proven to cause confusion as well as negative emotions such as anxiety and fear. Misinformation regarding proper safety measures for the prevention of the virus that go against information from legitimate institutions like the World Health Organization can also lead to inadequate protection and possibly place individuals at risk for exposure.
Misinformation has the power to sway public elections and referendums if it has the chance to gain enough momentum in the public discourse. Leading up to the 2016 United Kingdom European Union membership referendum for example, a figure widely circulated by the Vote Leave campaign claimed the UK would save £350 million a week by leaving the EU, and that the money would be redistributed to the British National Health Service. This was later deemed a "clear misuse of official statistics" by the UK statistics authority. The advert infamously shown off on the side of London's renowned double decker busses did not take into account the UK's budget rebate, and the idea that 100% of the money saved would go to the NHS was unrealistic. A poll published in 2016 by Ipsos MORI found that nearly half of the British public believed this misinformation to be true. Even when information is proven to me misinformation, it may continue to shape people's attitudes towards a given topic, meaning misinformation has the power to swing political decisions if it gains enough traction in public discussion.
Websites have been created to help people to discern fact from fiction. For example, the site FactCheck.org has a mission to fact check the media, especially politician speeches and stories going viral on the Internet. The site also includes a forum where people can openly ask questions about information they're not sure is true in both the media and the internet. Similar sites give individuals the option to be able to copy and paste misinformation into a search engine and the site will investigate the truthfulness of the inputted data. Famous online resources, such as Facebook and Google, have attempted to add automatic fact checker programs to their sites, and created the option for users to flag information that they think are false on their website. A way that fact checking programs find misinformation involve finding the truth by analyzing the language and syntax of news stories. Another way is that fact checkers can search for existing information on the subject and compare it to the new broadcasts being put online. Other sites such as popflock.com resource and Snopes are also widely used resources for verifying information.
Some scholars and activists are pioneering a movement to eliminate the mis/disinformation and information pollution in the digital world. The theory they are developing, "information environmentalism", has become a curriculum in some universities and colleges.