What is the methodology behind Ground News' media bias ratings?
Executive summary
Ground News assigns outlet bias by averaging the published ratings from three third‑party monitoring organizations: AllSides, Ad Fontes Media, and Media Bias/Fact Check (MBFC) [1]. Its factuality score is the average of Ad Fontes Media and Media Bias Fact Check ratings; bias and factuality apply to whole publications, not individual articles, and Ground News aggregates coverage from tens of thousands of outlets to show coverage distribution and “blindspots” [1] [2] [3].
1. How Ground News constructs its headline metric: an aggregator of expert ratings
Ground News does not produce primary bias ratings itself; instead it combines the ratings published by three independent monitoring organizations — AllSides, Ad Fontes Media, and Media Bias/Fact Check — and presents the average as the outlet’s bias label on the site and extension [1] [4]. Ground News publicly states this aggregation strategy on its methodology and About pages [1] [4]. Media Bias Fact Check’s own page about Ground News also confirms Ground News relies on those external raters rather than an internal proprietary bias‑scoring process [5].
2. What the averages measure — publication‑level bias and factuality, not article truth
Ground News’ bias labels and factuality scores are applied to entire publications, not to individual articles [6]. The platform’s “Factuality Score” is the average of Ad Fontes Media and Media Bias/Fact Check assessments, separate from the three‑way bias average [1]. Multiple library and review writeups emphasize that Ground News aggregates outlet‑level judgments and does not itself verify individual claims or issue separate fact checks [6] [7].
3. The visual tools: Bias Bar and Blindspot features
Ground News uses visualizations to show how different outlets across the political spectrum cover a story. The Bias Bar gives a birds‑eye view of coverage distribution — if mostly left‑leaning sources cover an item, the left side of the bar dominates — and the Blindspot feature flags stories disproportionately covered by one side [8] [1]. Those features depend on the outlet bias labels to map coverage across “left/center/right” groupings [8] [1].
4. How third‑party rater methodologies shape Ground News’ output
Because Ground News averages external ratings, the platform inherits the raters’ underlying choices: editorial reviews, blind surveys, independent research and other methods used by AllSides, Ad Fontes, and MBFC [1]. Ground News’ transparency page acknowledges that “each news monitoring organization has their own methodology,” and that its bias data are referenced from those third‑party organizations [9] [1].
5. Strengths: breadth, comparative context, and accessibility
Ground News aggregates tens of thousands of outlets and thousands of story summaries daily, allowing users to compare narrative frames across many publishers and to spot coverage gaps quickly [2] [3]. Reviews and guides highlight that the platform is useful for lateral reading — seeing “every side of every news story” — and for teaching how coverage choices create blindspots [3] [6].
6. Limitations and sources of potential bias
Ground News’ primary limitation is that it inherits the disagreements, methodological choices, and potential errors of the three rater organizations rather than independently adjudicating bias [1] [5]. Because ratings apply to outlets rather than pieces, a neutral label does not guarantee every article is balanced; conversely, a labeled outlet can publish articles that deviate from its average leaning [6] [7]. Critical reporting also notes aggregation and AI summarization can introduce issues — Ground News synthesizes many articles and publishes summaries at scale, which reviewers argue is not a substitute for original reporting or verification [2].
7. Competing perspectives in the reporting
Supporters argue Ground News offers an efficient, data‑driven way to expose readers to multiple frames and to detect “blindspots” in coverage [8] [3]. Critics — including a Columbia Journalism Review analysis — say aggregation plus appended bias labels isn’t a superior editorial approach, noting Ground News’ reliance on automated summarization and third‑party ratings may simply be a cheaper shortcut compared with original reporting and verification [2]. Media Bias Fact Check’s own profile of Ground News notes Ground News uses average ratings and reiterates that Ground News does not itself determine bias [5].
8. What the sources do not say
Available sources do not mention Ground News’ exact mathematical formula for averaging — for example, whether the three raters are weighted equally in every case, or how Ground News resolves missing ratings from one rater for specific outlets — beyond saying bias is “based on the average rating” of the three organizations [1]. Available sources also do not provide internal audit results showing how often the averaged label matches independent article‑level assessments (not found in current reporting).
9. Bottom line for users and educators
Ground News is a meta‑rating and aggregation tool: it offers visual context by averaging established bias raters and presenting comparative coverage, but it does not independently fact‑check individual claims or produce original bias research [1] [6] [7]. Users should treat its outlet labels as helpful signals derived from external raters — useful for comparing frames and spotting blindspots — while recognizing the platform’s methodological dependence on AllSides, Ad Fontes, and Media Bias/Fact Check and the inherent limits of outlet‑level averaging [1] [9] [5].