Which US media outlets are rated as left-leaning by bias trackers?
Executive summary
Major media‑bias trackers such as AllSides, Ad Fontes Media and newer aggregators like Biasly routinely place a set of mainstream U.S. outlets on the left/lean‑left part of their spectrum; examples commonly cited by library guides and bias‑chart summaries include The New York Times, The Washington Post and The Atlantic [1] [2] [3]. These placements reflect each tracker’s methodology and time‑bound sampling, and are disputed or qualified by critics who warn that bias charts are snapshots rather than absolute judgments [4] [5].
1. What “left‑leaning” means on bias charts and who is doing the rating
“Left‑leaning” on the major public charts is a relative label that combines a political‑leaning axis with a reliability or factuality metric — AllSides categorizes sources from Left to Right and offers “Lean Left” and “Left” labels, while Ad Fontes places outlets on a two‑dimensional grid of bias and reliability and updates its flagship chart biannually [1] [2] [6]. AllSides states its ratings reflect a blend of expert review and public input and intends to show the average view of Americans rather than a single evaluator’s judgment [7]. Ad Fontes emphasizes human analysts and balanced panels in its methodology and Biasly provides its own interactive mapping approach, meaning “left‑leaning” can result from different methods of sampling and scoring [4] [8].
2. Which U.S. outlets are routinely placed on the left or lean‑left
University and library guides that reference the major charts point to familiar national outlets as examples of slightly or lean‑left designations — the New York Times, the Washington Post and The Atlantic are specifically cited as rated slightly or generally left‑leaning by media bias charts in library summaries [3] [9] [10]. Those same guides and the AllSides site note that many other mainstream outlets populate the center‑left band on the larger charts, but the precise roster varies by tracker and by update cycle [1] [9].
3. Why charts disagree and why labels shift over time
Methodological differences explain much of the disagreement: Ad Fontes uses panels of analysts with left, center and right perspectives to rate articles for “expression,” “veracity” and “political position,” while AllSides combines expert review with crowd inputs and Biasly applies its proprietary scoring — all produce grids that change as outlets’ content mix evolves, especially when opinion programming grows or editorial lines shift [4] [7] [8]. Chart maintainers themselves warn that a chart is a snapshot and scores can and do move between editions, and independent library guides likewise urge caution about treating any single chart as definitive [6] [5].
4. Caveats, critiques and how to use these ratings responsibly
Scholars and media‑literacy librarians caution that bias charts are controversial tools: they can help readers spot patterns of partisan framing but also oversimplify complex editorial ecosystems and carry their own methodological assumptions [5] [9]. AllSides explicitly describes its Balance Certification and the limits of its labels, and public-facing charts frequently include reliability axes so consumers can see both lean and factuality rather than a single partisan score [1] [7]. The responsible use of these trackers is to treat them as guided entry points — to identify outlets commonly placed left or lean‑left (for example the New York Times, Washington Post, The Atlantic on many charts) — while consulting multiple trackers and primary content when assessing any claim about bias [3] [2] [8].