SourceScore vs Domain Authority
Methodology v0.1 · Published 2026-04-28 · Last reviewed 2026-04-30
Domain Authority predicts how well a domain will rank on a Google results page. SourceScore predicts whether an AI answer engine should cite that domain as a trustworthy source. Same rough 0–100 shape on the page — a different question underneath, and the two scores routinely disagree.
What Domain Authority actually measures
Domain Authority (DA) is a third-party metric published by Moz. Per Moz’s own documentation, DA is a machine-learning model trained to predict how a domain is likely to rank in Google search results, built primarily from the domain’s link graph — how many other domains link to it, and how authoritative those linking domains are. Moz is explicit that DA is not a Google ranking factor itself; it’s a comparative, third-party estimate useful for benchmarking one domain against another.
What the SourceScore Index actually measures
The SourceScore Index is a composite of three sub-scores — Citation Discipline, Modern Reference, and Citation Velocity — none of which is a link-graph signal. It measures editorial rigor (how a source backs its claims), machine-readability and freshness (how fit the content is to be extracted and cited by an AI system), and how often tier-1 publications and AI engines actually cite the source per week.
Why they diverge
A domain earns a high DA by accumulating a large, authoritative backlink profile — something that compounds mainly with age, marketing reach, and link-building activity. A domain earns a high SourceScore Index by publishing content an AI system can confidently extract and trust — something that compounds with editorial discipline, structured data, and demonstrated citation by tier-1 sources, independent of how many sites link to it. Neither factor implies the other: a decades-old, heavily-linked domain can still publish thinly-sourced content (high DA, low SourceScore), and a young, lightly-linked domain can already be a rigorously-cited, AI-extractable source (low DA, high SourceScore).
Which one should you use?
They answer different questions, so the right one depends on which discovery channel you care about. Optimizing for a Google results page is a Domain Authority question. Optimizing for being quoted, trusted, and cited inside an AI-generated answer is a SourceScore question. As more discovery happens through AI answer engines rather than a list of ranked links, the second question matters on its own — independent of, and not answered by, the first.
No fabricated numbers
SourceScore does not ingest, license, or display third-party Domain Authority scores for any named domain. Every claim above describes DA’s publicly documented methodology, not a specific domain’s live number — consistent with SourceScore’s own no-fabricated-data rule.
FAQ
Is SourceScore the same as Domain Authority?
No. Domain Authority (Moz) is a link-graph metric that predicts how well a domain will rank on a Google search results page. SourceScore is a citation-fitness metric that predicts whether an AI answer engine should treat a domain as a trustworthy, extractable source. They score different questions, so a domain's DA and its SourceScore commonly diverge.
Can a domain have high Domain Authority and a low SourceScore?
Yes. DA is built almost entirely from the domain's backlink profile — how many other sites (and how authoritative they are) link to it. A domain can accumulate a large, high-quality backlink profile over years while publishing content with thin sourcing, no structured data, and little standing as a cited authority in AI-generated answers — high DA, low SourceScore.
Can a domain have low Domain Authority and a high SourceScore?
Yes. A newer or smaller domain may not yet have accumulated many backlinks (low DA) while still publishing rigorously-cited, machine-readable, frequently-referenced content that AI engines pull into generated answers — low DA, high SourceScore. Citation Discipline and Modern Reference don't require a large link graph to score well.
Should I use Domain Authority or SourceScore?
Use DA when the question is "how likely is this domain to rank in traditional search?" Use SourceScore when the question is "how likely is this domain to be cited, trusted, and quoted by an AI answer engine?" The two questions increasingly diverge as more discovery happens through AI-generated answers rather than a list of blue links.