Does SEO_H1_SINGLE affect my score?

Yes. It is an importance 6 rule at RESEARCH confidence, so a failure costs 6 × 0.7 points of impact in the SEO category before that category is normalised to 100.

What does RESEARCH confidence mean?

Backed by large-sample study or industry research, not a specification. Confidence is a declared tier rather than a per-rule number, so every rule backed by the same class of evidence carries the same weight - which is what makes the score reproducible instead of hand-tuned.

How do I check SEO_H1_SINGLE on my own site?

Paste your URL into the box above and it runs only this rule, usually in a couple of seconds. It is also included in the SEO checker and in a full scan.

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Exactly one H1 per page

SEO_H1_SINGLE

Pages should have exactly one <h1> that describes the page's primary topic.

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How this rule is weighted

Importance: 6 / 10; How much this matters relative to other rules.
Confidence: RESEARCH; Backed by large-sample study or industry research, not a specification.
Severity: warning; How the finding is presented when it fails.
Scoring: Counts; A failure costs points in its category.

Impact is importance multiplied by the confidence tier’s weight — SPECIFICATION 1.0, RESEARCH 0.7, EMERGING 0.3, EXPERIMENTAL 0.1. Two rules backed by the same class of evidence therefore always carry the same weight, which is what makes the score reproducible rather than hand-tuned.

Questions about this rule

Does SEO_H1_SINGLE affect my score?: Yes. It is an importance 6 rule at RESEARCH confidence, so a failure costs 6 × 0.7 points of impact in the SEO category before that category is normalised to 100.
What does RESEARCH confidence mean?: Backed by large-sample study or industry research, not a specification. Confidence is a declared tier rather than a per-rule number, so every rule backed by the same class of evidence carries the same weight - which is what makes the score reproducible instead of hand-tuned.
How do I check SEO_H1_SINGLE on my own site?: Paste your URL into the box above and it runs only this rule, usually in a couple of seconds. It is also included in the SEO checker and in a full scan.

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