Have any US news outlets changed their bias ratings significantly during 2023–2025 and why?

1. Who is doing the rating and how often they change their minds

Three widely used projects—AllSides, Ad Fontes Media (Media Bias Chart) and several newer interactive charts such as Biasly—publish regular bias-and-reliability placements and explicitly revise those placements on a schedule, with AllSides running blind surveys and editorial reviews and Ad Fontes updating its flagship chart twice per year ^{[3] [1] [2] [4]}.

2. Concrete moves recorded 2023–2025: examples and scale

AllSides documented category moves in that period: its May 2023 Media Bias Chart release and subsequent updates included several rating reclassifications (AllSides’ Version 9 notes changes around May 2023), and its internal editorial reviews in 2025 shifted or clarified placements for named outlets — for example, the Daily Mail was moved from Right to Lean Right in a 2025 editorial update and AllSides’ panel re‑rated some outlets after blind surveys produced divergent public ratings ^{[1] [5]}. Ad Fontes’ public timeline shows the chart being refreshed twice a year through 2025, meaning many outlets’ plotted positions moved subtly over successive editions rather than flipping dramatically in a single step ^[2].

3. Why ratings changed: methodology, evidence and editorial reviews

The rating organizations themselves point to a few clear drivers: systematic blind‑bias surveys of readers, cross‑ideological reviewer panels, and targeted editorial reviews when survey results or new reporting patterns raise questions — AllSides explicitly describes using left/center/right reviewers and blind surveys to detect shifts, and it carried out multiple editorial reviews in 2025 for outlets whose blind ratings diverged from panel verdicts ^{[3] [1] [5]}. Ad Fontes emphasizes a reproducible methodology and periodic re‑evaluation of sources, which produces incremental movement when reliability or tone assessments change across the sampling windows ^{[6] [2]}.

4. What those changes mean in practice: gradual re‑sorting, not wholesale realignment

Across the reporting, the pattern is one of modest re‑sorting rather than wholesale reversals: some outlets nudged from “Right” to “Lean Right” or from “Center” toward a lean when subtle cues or topic‑specific coverage trends emerged, rather than large corps‑wide ideological flips; the organizations warn users that “Center” does not equal neutral and that single articles can deviate from an outlet’s overall rating ^{[5] [7]}.

5. Alternative viewpoints and limits of the record

Caveats appear in the sources themselves: AllSides acknowledges editorial discretion in which outlets appear on the chart and that community voting can produce mixed results, while university guides and libraries use both AllSides and Ad Fontes but also note ownership and topic‑specific shifts are important contextual factors that the charts may not fully capture ^{[3] [8] [6]}. The publicly available snippets document specific 2023–2025 adjustments and methods, but they do not provide a comprehensive list of every outlet that moved or a full causal forensic history of editorial decisions inside each outlet; that level of detail is not contained in the cited material ^{[1] [2]}.

6. Bottom line: yes — but mostly measured, method‑driven changes

The evidence in these projects shows that a number of U.S. outlets saw their bias placements shift between 2023 and 2025, and those shifts were typically modest and traceable to repeat blind surveys, editorial review panels, and scheduled chart updates rather than to single sensational events; the rating bodies’ own transparency about methods and their admission of editorial discretion are central to understanding why changes happened ^{[1] [3] [2]}.