CODEBOOK.md

CRED-1 Codebook

Version 1.0 — February 2026

This codebook documents all variables in the CRED-1 dataset. The dataset is distributed in three formats: a full JSON file, a CSV file for research analysis, and a compact JSON file for on-device embedding.

JSON Format (cred1_current.json)

JSON object mapping domain names (string keys) to full metadata objects with all enrichment signals and score components.

Field	Type	Range	Description
category	string	fake,unreliable,mixed,conspiracy,satire,reliable	Full category name. See Category Taxonomy.
credibility_score	float	0.00-1.00	Composite credibility score. Lower values indicate lower credibility. See Scoring Model.
sources	integer	1-2	Number of independent source lists that flag this domain.
tranco_rank	integer	1-1,000,000	Tranco Top-1M rank. Optional - absent if not ranked.
domain_registered	string	ISO 8601	Domain registration date from RDAP. Optional - absent if RDAP lookup failed.
domain_age_years	float	0.0-35.0+	Domain age in years, computed from domain_registered. Optional.
iffy_factual	string	VL,L,M,MH,H,VH	MBFC Factual Reporting rating. Optional - absent if not from Iffy.news.
iffy_bias	string	e.g. FN,R,RC,C,LC,L	MBFC political bias rating. Optional.
iffy_score	float	0.0-1.0	Iffy.news credibility score. Optional.
factcheck_claims	integer	1+	Google Fact Check Tools API claim count. Optional - absent if zero.
safe_browsing_flagged	boolean	true/false	Google Safe Browsing threat flag. Optional.
score_cat	float	0.0-1.0	Category-based score component.
score_iffy	float	0.0-1.0	Iffy.news score component.
score_tranco	float	0.0-1.0	Tranco rank score component.
score_age	float	0.0-1.0	Domain age score component.
score_factcheck	float	0.0-1.0	Fact-check frequency score component.
score_safebrowsing	float	0.0-1.0	Safe Browsing score component.

Example

{
  "infowars.com": {
    "category": "fake",
    "credibility_score": 0.14,
    "domain_age_years": 26.4,
    "domain_registered": "1999-10-04T04:00:00Z",
    "factcheck_claims": 52,
    "iffy_bias": "FN",
    "iffy_factual": "VL",
    "iffy_score": 0.1,
    "score_age": 0.2,
    "score_cat": 0.05,
    "score_factcheck": 0.0,
    "score_iffy": 0.1,
    "score_safebrowsing": 0.05,
    "score_tranco": 0.1,
    "sources": 2,
    "tranco_rank": 4382
  }
}

Missing Values

Optional fields are omitted entirely when unavailable. A domain not present in the dataset should be treated as neutral/unknown (not as reliable).

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CSV Format (cred1_current.csv)

CSV file with the same fields as JSON, sorted by credibility_score ascending (least credible first).

Source Data Fields

Column	Type	Values / Range	Description	Source
domain	string	e.g. infowars.com	Normalized domain name (lowercase, no www. prefix, no trailing slash)	Merged
category	string	See Category Taxonomy	Unified credibility category	Merged
sources	integer	1-2	Number of independent source lists that flag this domain.	Merged
iffy_factual	string	VL, L, M, MH, H, VH, ``	MBFC Factual Reporting rating as provided by Iffy.news. Empty if domain is only in OpenSources.	Iffy.news
iffy_bias	string	e.g. FN, R, RC, C, LC, L, LEFT, ``	MBFC political bias rating. Empty if not from Iffy.news.	Iffy.news
iffy_score	float	0.0–1.0, or empty	Iffy.news credibility score. Lower = less credible. Empty if not from Iffy.news.	Iffy.news

Enrichment Signal Fields

Column	Type	Values / Range	Description	Source
tranco_rank	integer	1–1,000,000, or empty	Position in the Tranco Top-1M list. Lower = more popular. Empty if domain not ranked.	Tranco
domain_age_years	float	0.0–35.0+, or empty	Years since domain registration (computed from RDAP registration date to dataset build date). Empty if RDAP lookup failed.	RDAP
domain_registered	string (ISO 8601)	e.g. 1999-03-07T05:00:00Z, or empty	Domain registration date as returned by RDAP. Empty if unavailable.	RDAP
factcheck_claims	integer	0+, or empty	Number of fact-check claims found via Google Fact Check Tools API. Empty if zero or not queried.	Google Fact Check Tools API
safe_browsing_flagged	boolean	True, or empty	Whether Google Safe Browsing flagged this domain as malware or social engineering. Empty if not flagged.	Google Safe Browsing API

Scoring Fields

Column	Type	Range	Description
credibility_score	float	0.000–1.000	Composite credibility score. See Scoring Model.
score_cat	float	0.0–1.0	Category-based score component.
score_iffy	float	0.0–1.0, or empty	Iffy.news score component. Empty if domain not from Iffy.news.
score_tranco	float	0.0–1.0, or empty	Tranco rank component (log-normalized). Empty if not ranked.
score_age	float	0.0–1.0, or empty	Domain age component (normalized, capped at 20 years). Empty if age unknown.
score_factcheck	float	0.0–1.0, or empty	Fact-check frequency component (log-scaled inverse). Empty if no claims.
score_safebrowsing	string	flagged, or empty	Safe Browsing override indicator. If flagged, composite score is hard-capped at 0.05.

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Compact Format (cred1_compact.json)

Minimal JSON format for on-device embedding in browser extensions and mobile applications. Uses short keys and no whitespace for minimal file size (~168KB).

Key	Type	Description
s	float	Credibility score (same as credibility_score)
c	string	Category code: f, u, m, c, s, r
n	integer	Number of sources
r	integer	Tranco rank (optional)
d	string	Domain registration date as YYYY-MM-DD (optional)

Example

{"infowars.com":{"c":"f","d":"1999-10-04","n":2,"r":4382,"s":0.14},"theonion.com":{"c":"s","d":"1996-08-05","n":1,"r":7429,"s":0.34}}

---

Category Taxonomy

Domains are classified into six categories based on consensus labels from OpenSources.co and Iffy.news. When a domain appears in both sources, the lower credibility category takes precedence.

Category	Code	Base Score	Definition
fake	f	0.0	Sources that fabricate information, publish deceptive content, or impersonate legitimate news outlets.
conspiracy	c	0.1	Sources that consistently promote conspiracy theories not supported by evidence.
unreliable	u	0.2	Sources that may publish some factual content but regularly fail basic standards of journalistic accuracy. Includes clickbait, junk science, and hate speech sources.
satire	s	0.3	Sources that use humor, irony, or exaggeration. Not malicious, but content is not factual.
mixed	m	0.5	Sources with a mixed track record — some factual reporting alongside biased, misleading, or unverified content.
reliable	r	1.0	Sources generally considered reliable by fact-checking organizations. Note: CRED-1 contains very few reliable sources (n=8) as the upstream datasets focus on unreliable sources.

OpenSources.co Category Mapping

Original Label	→ CRED-1 Category
fake, fake news	fake
conspiracy	conspiracy
unreliable, clickbait, junksci, hate, rumor	unreliable
satire, satirical	satire
bias, political, state	mixed
reliable	reliable
blog	other

Iffy.news Factual Rating Mapping

MBFC Factual Rating	→ CRED-1 Category
VL (Very Low)	fake
L (Low)	unreliable
M (Mixed)	mixed
MH (Mostly High)	mostly_reliable
H (High), VH (Very High)	reliable

---

Scoring Model

The composite credibility score is computed as a weighted blend of up to five signals:

S = 0.50 × s_cat
  + 0.15 × s_iffy        (if available)
  + 0.15 × s_factcheck   (if available)
  + 0.05 × s_tranco      (if available)
  + 0.05 × s_age         (if available)
  + w_fill × s_cat       (remaining weight)

Where w_fill = 1.0 - sum(active weights) fills in for missing signals using the category score.

Override: If safe_browsing_flagged = True, the final score is hard-capped at 0.05 regardless of other signals.

Signal Normalization

Signal	Formula	Interpretation
s_cat	Lookup table (see Category Taxonomy)	Category label → fixed score
s_iffy	Raw Iffy.news score (already 0.0–1.0)	Lower = less credible
s_tranco	1.0 - log10(rank) / 6.0, clamped to [0, 1]	Rank 1 → 1.0, Rank 1M → 0.0
s_age	min(1.0, age_years / 20.0)	0 years → 0.0, 20+ years → 1.0
s_factcheck	max(0.0, 1.0 - log10(claims) / 1.7)	1 claim → 0.8, 50+ claims → 0.0

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Important Usage Notes

1. Absence ≠ reliable: A domain not in the dataset should be treated as unknown/neutral, not as trustworthy. CRED-1 is a list of domains with known credibility issues.

2. Score = composite indicator: The credibility score is an aggregated heuristic, not a ground truth. It should be used as one signal among many.

3. Temporal validity: Domain credibility can change over time. CRED-1 v1.0 reflects the state of source data as of February 2026.

4. English-language bias: The majority of domains in the upstream sources are English-language outlets. Coverage of non-English misinformation sources is limited.

5. No personal data: The dataset contains only domain-level metadata. No personally identifiable information is included.

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