Media Bias/Fact Check
American website
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Media Bias/Fact Check (MBFC) is an American media watchdog website founded in 2015 by Dave M. Van Zandt.[1] It considers four main categories and multiple subcategories in assessing the "political bias" and "factual reporting" of media outlets,[2][3] relying on a self-described "combination of objective measures and subjective analysis".[4][5] It is widely used but has been criticized for its methodology.[6] Scientific studies,[7] using its ratings, found that ratings from Media Bias/Fact Check show high agreement with an independent fact checking dataset from 2017,[8] NewsGuard,[9] and BuzzFeed journalists.[10]
| Founded | 2015 |
|---|---|
| Headquarters | Greensboro, North Carolina |
| Owner | Dave M. Van Zandt |
| URL | mediabiasfactcheck |
| Current status | Active |
Methodology
Four main categories are used by MBFC to assess political bias and factuality of a source. These are: (1) use of wording and headlines (2) fact-checking and sourcing (3) choice of stories and (4) political affiliation. MBFC additionally considers subcategories such as bias by omission, bias by source selection, and loaded use of language.[2][11] A source's "Factual Reporting" is rated on a seven-point scale from "Very high" down to "Very low".[12]

Political bias ratings are U.S.-centric,[11][13] and are "extreme-left", "left", "left-center", "least biased", "right-center", "right", and "extreme-right".[14] The category "Pro-science" is used to indicate "evidence based" or "legitimate science". MBFC also associates sources with warning categories such as "Conspiracy/Pseudoscience", "Questionable Sources", and "Satire".[3]
Fact checks are carried out by independent reviewers who are associated with the International Fact-Checking Network (IFCN) and follow the International Fact-Checking Network Fact-checkers' Code of Principles, which was developed by the Poynter Institute.[15][11] A source may be credited with high "Factual Reporting" and still show "Political bias" in its presentation of those facts, for example through its use of emotional language.[16][17][18] Only failed fact checks and "confirmed cases of misinformation" that have occurred within the past five years can be counted against a source.[11] According to the methodology, an evaluation requires "a minimum of 10 headlines and 5 full news stories from each source" to be reviewed.[11]
Reception
MBFC has been used in studies of mainstream media, social media, and disinformation,[19][8][20][21] among them single- and cross-platform studies of services including TikTok, 4chan, Reddit, Lemmy, Twitter, Facebook, Instagram, and Google Web Search.[22] When MBFC factualness ratings of "mostly factual" or higher were compared to an independent fact checking dataset's "verified" and "suspicious" news sources, the two datasets showed "almost perfect" inter-rater reliability.[8][20][23] A 2022 study that evaluated sharing of URLs on Twitter and Facebook in March and April 2020 and 2019, to compare the prevalence of misinformation, reported that scores from Media Bias/Fact Check correlate strongly with those from NewsGuard (r = 0.81).[9]
A comparison of five fact checking datasets frequently used as "groundtruth lists" suggested that choosing one groundtruth list over another has little impact on the evaluation of online content.[8][20] In some cases, MBFC has been selected because it categorizes sources using a larger range of labels than other rating services.[8] MBFC offers the largest dataset covering biased and low factual news sources. Over a 4-year span, the percentage of links that could be categorized with MBFC was found to be very consistent. Research also suggests that the bias and factualness of a news source are unlikely to change over time.[8][20] The site has been used by researchers at the University of Michigan to create a tool called the "Iffy Quotient", which draws data from MBFC and NewsWhip to track the prevalence of "fake news" and questionable sources on social media.[24][25]
A 2018 year-in-review and prospective on fact-checking from the Poynter Institute, which develops PolitiFact,[26] cited a proliferation of credibility score projects, including MBFC, writing, "While these projects are, in theory, a good addition to the efforts combating misinformation, they have the potential to misfire", and stating that "Media Bias/Fact Check is a widely cited source for news stories and even studies about misinformation, despite the fact that its method is in no way scientific."[27] Also in 2018, a writer in the Columbia Journalism Review described MBFC as "an armchair media analysis",[6] and characterized their assessments as "subjective assessments [that] leave room for human biases, or even simple inconsistencies, to creep in".[28] A 2020 study published in Scientific Reports wrote: "While [Media Bias/Fact Check's] credibility is sometimes questioned, it has been regarded as accurate enough to be used as ground-truth for e.g. media bias classifiers, fake news studies, and automatic fact-checking systems."[19]