signal-definitions.md

Signal definitions

Relevance levels

Relevance combines deterministic page/context similarity signals and is represented as:

• low
• medium
• high
• very_high

Thresholds are intentionally visible in the source code and may evolve with benchmark data.

Placement values

• editorial_context: link detected inside <main> or <article>.
• navigation: link detected inside <nav> or <header>.
• sidebar: link detected inside <aside>.
• footer: link detected inside <footer>.
• unknown: HTML structure is insufficient to make a confident landmark classification.

Review flags

Examples include:

• high_external_link_density
• many_unique_external_domains
• many_followed_external_links
• source_not_indexable
• source_unavailable
• target_unavailable
• sponsored_attribute_present
• weak_context_match_manual_review_required

A flag means "inspect this evidence," not "Google considers this link spam."

Confidence

Confidence describes how complete the observable evidence is. It is not confidence in ranking impact.