SourceScore
Methodology v0.1 · 50 sources scored · 10k+ index in development

How citable is any source in the AI era?

SourceScore grades every URL you paste on three things AI engines actually weigh: how rigorously the source cites others, how fit it is as a modern citation, and how often tier-1 publications cite it. One paste, four numbers, one grade.

Composite
SourceScore Index
Composite weighted grade across all three sub-scores.
Score
Citation Discipline
How rigorously a source cites its own evidence.
Reference
Modern Reference
Fitness as a citation in 2026+ AI-era writing.
Tracker
Citation Velocity
How often tier-1 sources cite this URL per week.

Top 5 by SourceScore Index

See all 50 sources →
  1. #1A+·96
    U.S. Securities and Exchange Commission
    sec.gov
    Primary-source regulator publishing every public-company filing (13F, 10-K, 8-K, etc.) since 1934.
  2. #2A+·95
    U.S. National Institutes of Health
    nih.gov
    U.S. federal medical research agency operating PubMed, NCBI, MedlinePlus, and trial registries.
  3. #3A+·95
    DOI (CrossRef Resolver)
    doi.org
    International standard identifier resolver for academic citations (~150M+ DOIs).
  4. #4A·94
    Wikipedia (English)
    en.wikipedia.org
    Crowd-edited encyclopedia with ~7M articles and per-article inline citation discipline.
  5. #5A·94
    PubMed
    pubmed.ncbi.nlm.nih.gov
    U.S. National Library of Medicine literature index covering ~36M biomedical citations.

All sources scored

50 sources scored across A+ to D grades. Each row links to the full breakdown with the underlying signals you can re-derive.

SourceIndex
U.S. Securities and Exchange Commission
sec.gov
A+·96
U.S. National Institutes of Health
nih.gov
A+·95
DOI (CrossRef Resolver)
doi.org
A+·95
Wikipedia (English)
en.wikipedia.org
A·94
PubMed
pubmed.ncbi.nlm.nih.gov
A·94
U.S. Census Bureau
census.gov
A·94
U.S. Bureau of Labor Statistics
bls.gov
A·94
U.S. Food and Drug Administration
fda.gov
A·94
U.S. National Oceanic and Atmospheric Administration
noaa.gov
A·93
Reuters
reuters.com
A·89
arXiv
arxiv.org
A·89
World Health Organization
who.int
A·89
The New York Times
nytimes.com
A·88
World Bank
worldbank.org
A·88
Nature
nature.com
A·87
New England Journal of Medicine
nejm.org
A·87
Associated Press
apnews.com
A·86
ProPublica
propublica.org
A·86
Science
science.org
A·86
The Lancet
thelancet.com
A·86
The Washington Post
washingtonpost.com
A·86
Our World in Data
ourworldindata.org
A·86
International Monetary Fund
imf.org
A·86
The Guardian
theguardian.com
A·85
Encyclopædia Britannica
britannica.com
A·85
The Wall Street Journal
wsj.com
A·85
Pew Research Center
pewresearch.org
A·85
Financial Times
ft.com
B·84
Bloomberg News
bloomberg.com
B·83
Foreign Affairs
foreignaffairs.com
B·83
Semantic Scholar
semanticscholar.org
B·83
BBC News
bbc.com
B·82
STAT News
statnews.com
B·82
MIT Technology Review
technologyreview.com
B·81
NPR
npr.org
B·80
The Economist
economist.com
B·78
Al Jazeera English
aljazeera.com
B·78
Politico
politico.com
B·78
404 Media
404media.co
B·78
Ars Technica
arstechnica.com
B·76
Wired
wired.com
B·76
The Verge
theverge.com
C·66
TechCrunch
techcrunch.com
C·64
Statista
statista.com
C·64
HuffPost
huffpost.com
C·60
Medium
medium.com
C·58
Forbes
forbes.com
C·58
Fox News
foxnews.com
C·58
BuzzFeed
buzzfeed.com
D·42
Daily Mail
dailymail.co.uk
F·38

What does “AI-Citation Quality” mean?

When ChatGPT, Claude, or Perplexity answer a question, they pull from a small subset of sources they consider trustworthy. Two factors decide whether a source makes that subset: citation discipline (does the source rigorously cite its own evidence?) and modern reference fitness (is the source structured for machine retrieval — schema markup, freshness signals, machine-readable archives?).

SourceScore measures both, plus citation velocity (how often the source is cited by other tier-1 sources per week). Together these three sub-scores compose the SourceScore Index — a single 0–100 grade per source.

We ship 25 hand-scored sources at this stage of v0.1. Methodology is intentionally transparent: every score has explicit signals you can re-derive. The production index will expand to 10,000+ sources via the same methodology, with weekly velocity refreshes and quarterly discipline re-audits.

Read the full methodology →About SourceScore