Heading Hierarchy

Heading hierarchy is the order of the h1 to h6 elements on a page, each sitting one level below the heading it belongs to, so that the headings read on their own as an outline of the page. It is what tells a machine which passage answers which question.

What the HTML standard says

The HTML Standard defines six heading levels and a conformance rule for their order: each heading’s level may be lower than, equal to, or exactly one greater than the heading before it. Going from h2 to h4 breaks the rule. The standard permits more than one h1 and recommends, without requiring, that at least one heading be level one. It also defines the document outline as the headings in tree order, meant for building a table of contents, which is a fair description of what a crawler does with them too. A page whose heading list reads as a coherent outline has told the machine its structure; a page whose headings were chosen for font size has not.

Headings as questions

In a page written to be quoted, the heading states the question and the passage beneath answers it, and nothing else sits between. The hierarchy is what binds them: the passage under an h3 belongs to that h3 and to the h2 above it, so a machine knows what the span is an answer to. The audit this site ran on 9,483 small-business sites in September 2026 found the binding broken more often than absent. 50.7% of the sites had at least one heading phrased as a question and did not isolate an answer under it; the heading promised, the structure did not deliver. The full count is in what 9,483 small business websites serve to an AI crawler.

A common question

Is a heading phrased as a question enough to get the text beneath it quoted?

No, because the promise and the structure are separate things. The hierarchy is what binds a passage to the heading above it, so a machine knows what the span is an answer to; a heading that skips a level, or one picked for its font size, never makes that binding. In the audit of 9,483 small-business sites, 50.7% carried at least one question-shaped heading with no isolated answer under it. The heading asked, and nothing below it was left free-standing enough to serve as the reply.

Sources

Heading levels, order and outline: WHATWG HTML Standard, sections. The 50.7% figure is this site’s own; sample drawn per metro and trade, percentages describe the sample.