Methodology Chapter 06 of 08

Where a publisher's ratings come from.

Every article arrives carrying its publisher's record: a political lean, a factual-reporting grade, and a credibility rating. Mosaic News produces none of them. They are the work of Media Bias/Fact Check, an independent media watchdog that reviews newsrooms against their accuracy record. Mosaic licenses their ratings and shows each one with its source and its review date attached, so you can check their reasoning and disagree with it.

Every rating, sourced.

The New York Times

Est. 1851 · New York City

Founded in 1851, The New York Times is an American daily newspaper based in New York City and published by The New York Times Company.

Lean

Factuality

Credibility

Reach Global

Your Preference

What each rating describes

Five things are shown about a publisher, and each is credited to whoever produced it. Only one of them reaches your feed. The rest are there so you can weigh a source for yourself.

Political lean Where does its coverage sit? Media Bias/Fact Check: MBFC's placement of the outlet on a left-to-right scale, in seven bands from Extreme Left through Least Biased to Extreme Right. It describes the outlet's body of work, not the article you happen to be reading, and it is what sorts a Story's coverage into perspective columns.
Factual reporting How well does its reporting hold up? Media Bias/Fact Check: MBFC's grade from Very High to Low, drawn from the outlet's sourcing and its record of corrections and failed fact checks. This is the one rating that reaches your feed: it is the Source Credibility signal in the Feed Formula.
Credibility What is its overall standing? Media Bias/Fact Check: MBFC's summary of an outlet's bias and factual record together, as a single High, Medium, or Low. It is shown for orientation and is not scored.
Ownership Who owns it, and what kind of owner is that? Assessed by Mosaic; taxonomy by Ground News: The named owner is researched from publisher profiles, including MBFC and Wikipedia. Mosaic manually reviews that information and assigns one of Ground News's eight ownership categories. Ownership is never scored; it is here because knowing who funds a newsroom is part of reading it.
Reach How widely read is it? Tranco: The outlet's rank among the world's most-visited sites, from the Tranco research list. Reach measures size and nothing else: a small outlet is treated as small, never as worse, and you can weight it down to nothing if you would rather the size of a newsroom did not count at all.

Who decides, and how to check it

Rating a newsroom is a judgment, and a judgment is only worth showing you if you can see who made it and go and read their reasoning.

Media Bias/Fact Check makes the call

MBFC reviews a newsroom's sourcing, its corrections, and its failed fact checks, and publishes a bias rating, a factual-reporting grade, and a credibility rating for each one. Mosaic licenses that work and applies it as it stands. It does not produce a rating, adjust one, or overrule one it disagrees with.

Every rating names MBFC and its date

Each one carries a link to the MBFC page it came from and the date that assessment was last reviewed, so their reasoning is always one tap away. A rating you cannot trace is a rating you cannot check, and checking it is the point.

Facts about the outlet are cited separately

Founding year, headquarters, newsroom size, and ownership history come from Wikipedia and are marked where they appear. Mosaic's ownership category is labeled separately as Mosaic's assessment, so a source fact is never mistaken for our classification.

Other raters are one tap away

AllSides and Ad Fontes Media assess many of the same outlets by different methods and do not always agree. Where either has published an assessment, the publisher's page links straight to it, because one organization's view is still one view.

Bias, factual-reporting, and credibility ratings throughout Mosaic News are licensed from Media Bias/Fact Check and displayed with attribution. MBFC publishes how it produces them at mediabiasfactcheck.com/methodology. Traffic ranks come from the Tranco research list.

The app makes the same statement in the place it matters most: at the bottom of every publisher's report, naming its sources and pointing at the raters who disagree.

How Mosaic assigns ownership

Ownership categories are different from MBFC's ratings. Ground News created the taxonomy and definitions; Mosaic makes the publisher-level assessment. Our manual review considers ownership evidence from MBFC and Wikipedia, assigns one category, and stores that result on the publisher's profile. The category describes the publisher, never the quality or independence of an individual article.

Review the publisher profile

Mosaic reviews the ownership information available in each publisher's Media Bias/Fact Check and Wikipedia profiles. These sources provide the evidence; neither one assigns Mosaic's final category.

Assign one category per publisher

Mosaic manually reviews that evidence against the eight definitions below. The result is stored publisher by publisher rather than inferred from an article or generated when a Story loads.

Keep missing evidence visible

If Mosaic has not assigned a category, the app says Unknown. It does not infer ownership from a publisher's name, politics, reach, or the story being covered.

The eight ownership categories

These definitions follow Ground News's published methodology. In the app, tapping a category beside the ownership chart shows the same definition and identifies Mosaic as the assessor.

Media Conglomerates Definition by Ground News: A collection of radio, television, print and other news sources owned by the same entity, typically formed through a series of mergers and acquisitions. This includes any entity that owns a large majority of news outlets. Although typically large and national, it also includes smaller companies that own a significant number of outlets in a geographical area.
Private Equity Definition by Ground News: Media outlets that have been purchased by private equity funds, either through a leveraged buyout of the news property or the buyout of its owner. Private equity funds in the media space typically roll up several news properties in order to cut costs while increasing profit margins. They are often accused of pushing profits over news quality.
Individual Definition by Ground News: Individuals with a net worth in the tens of millions or greater who have a significant stake in a media outlet. Everyone in this category built their wealth outside of the media landscape and used it to buy news assets.
Government Definition by Ground News: Primarily government-funded news sources which may be independently managed or explicitly used for issuing government-approved media.
Telecom Definition by Ground News: Primarily connectivity providers that own phone, TV, internet or wireless mobility. Companies in this category have started vertically integrating to buy or create their own media assets, therefore owning both the infrastructure and content that you consume.
Corporation Definition by Ground News: Media sources owned by corporations that aren't media conglomerates or private equity firms. While it can be assumed that the interests of the corporate owner influence coverage, the degree of influence varies per outlet. Example: The South China Morning Post, which is owned by Alibaba.
Independent Definition by Ground News: Media that is free of influence by government or corporate interests. These outlets are not owned by any of the other classifications. Given the complexity of corporate cross-holdings and shell companies, any ownership stake greater than the publicized 5% cut-off is considered influence on the news source.
Other Definition by Ground News: Sources that could not be appropriately classified or that do not fall under one of the existing categories.

How a lean is decided

Lean is the most consequential rating on the page, because it decides how a Story's coverage is split when Mosaic shows you how the left and the right framed the same event. Three rules govern it.

A number sets the position

How far left or right an outlet sits is taken from its numeric bias score and placed in one of seven published bands. The score is what decides the band, the colour, and which column the outlet stands in when a Story's coverage is broken down by perspective.

The wording stays as published

The text on the pill is the rating as its source wrote it, shown verbatim rather than paraphrased into something tidier. Where that source uses a term describing an outlet's credibility rather than its politics, the term is still shown as written, and the outlet's left-right position continues to come from its score.

An unrated outlet stays unrated

An outlet with no lean rating is labeled as such and counted in no column. It is never quietly filed as Center, and a summary of how the left and right framed a Story is never built from coverage whose lean is unknown.

The lean card as it appears in the app: the band, the source's own reasoning, and a row of independent raters to check it against.

When an outlet has no rating

Not every outlet has been assessed. What a missing rating is worth depends on how often that rating is present elsewhere, so the two signals that use one treat its absence differently.

Not knowing is not the same as knowing it is bad

An outlet with no factual-reporting grade scores 3 out of 10 for Source Credibility rather than 0. The absence of a rating says nothing about the newsroom, so it is not treated as evidence against it.

Reach works the other way

An outlet with no traffic rank scores 2 out of 10. Almost every outlet Mosaic carries is ranked, so a missing rank genuinely does suggest a small readership. The two rules differ because the evidence differs, not because one signal is favoured.

The exact bands

No model decides a publisher's rating. Each one is a published band with a stated range, so the same score always produces the same result. Both scales are reproduced here in full.

The seven political lean bands

The bias score runs from −10 to +10. Negative is left, positive is right, and the middle band is where an outlet is judged to lean neither way.

Extreme Left: −10 to −8
Left: −7.9 to −5
Left-Center: −4.9 to −2
Least Biased: −1.9 to +1.9
Right-Center: +2 to +4.9
Right: +5 to +7.9
Extreme Right: +8 to +10

The five factual-reporting grades

This is the scale behind Source Credibility, and the score each grade earns out of 10. An outlet with no grade at all scores 3.

Very High: scores 10
High: scores 8
Mostly Factual: scores 5
Mixed: scores 2
Low: scores 0

The boundary

What a rating does not tell you

Mosaic does not make the political-lean, factual-reporting, or credibility judgments. Media Bias/Fact Check makes those ratings and every one carries their name. Ownership is different: Mosaic makes that category assessment and labels it as ours.
A lean is not a quality score. Where an outlet sits on the left-right scale has no effect on how it ranks. Mosaic never rewards or penalises a publisher for its politics, and lean is used only to compare perspectives on a Story.
A rating describes a newsroom, not the article in front of you. A weakly rated outlet can publish a careful piece, and a strongly rated one can publish a poor piece. The rating does not move either way.
Ratings have dates. Each carries the date it was last reviewed, and an outlet can change faster than an assessment of it does.
More of the outlets Mosaic carries are rated left of centre than right of centre. That is a property of which outlets have been rated, not a target, and it is worth knowing when you read a Story's perspective breakdown.

Where a publisher's ratings come from.

Every rating, sourced.

The New York Times

The Assessment

Political Lean

Factual Record

Ownership & Funding

Ownership Type

Quick Facts

History

Methodology